Propagation tray and propagation tray assembly

Abstract

Plant propagation trays and tray assemblies are disclosed. A propagation tray may comprise a base having a two-dimensional array of spaced-apart spikes extending from the base. Each spike comprises a central axis with a plurality of curved longitudinal fins arranged about the central axis and extending radially therefrom. A side profile of each fin forms a curved web between the central axis of the spike and the base. In use, the spikes act as support members that receive and support at least a portion of a growing medium plug.

Description

[0001] PROPAGATION TRAY AND PROPAGATION TRAY ASSEMBLY

[0002] CROSS-REFERENCES TO RELATED APPLICATIONS

[0003] This application claims priority from South African provisional patent application number 2024 / 00001 filed on 2024 / 07 / 02 as well as South African provisional patent application number 2024 / 05583 filed on 2024 / 07 / 18, which are both incorporated by reference herein.

[0004] FIELD OF THE INVENTION

[0005] This invention relates to a propagation tray assembly. In particular, this invention relates to a propagation tray assembly for use in the propagation of various crop types. Even more particularly the propagation tray assembly may find application in methods using growing-medium plugs to cultivate cuttings, seeds or seedlings.

[0006] BACKGROUND TO THE INVENTION

[0007] Plant propagation is the process by which new plants grow from various sources such as seeds, cuttings, seedlings or other suitable plant propagation material. Common propagation methods include seed propagation, cuttings such as stem cuttings, leaf cuttings or root cuttings, layering, division, grafting, budding, and tissue culture propagation techniques.

[0008] A well-known seedling propagation method employed in the home and garden, agricultural and forestry industry is the use of plant plugs or growing-medium plugs grown in so-called propagation trays, also known as nursery trays, planter trays, seed trays or seedling trays. This propagation method is believed to allow for minimum root disturbance when transplanting or potting on, that is planting into a larger pot for further propagation. Each growing-medium plug includes a plant propagate or plant propagation material such as a cutting, seed or seedling in a rooting medium, which may or may not be encased in a biodegradable sleeve. Once the relevant seedling has sufficiently rooted within the plug, the growing-medium plugs are planted out in a field or potted on. Each plug provides a ready-to-plant unit which has been adequately nurtured through propagation and early growth stages for easy removal and re-planting by an end user, consumer or nursery.

[0009] Growing-medium plugs or plant plugs are generally young plants, either seedlings or cuttings, grown in single units with root or growing medium in demarcated or modular trays. Various types of propagation trays are used in the agricultural and forestry industry for propagation using said growing-medium plugs. Well-known examples of such trays typically comprise a base with a plurality of fixed individual recesses, also described as “pockets”, “cups” or “pods”, each recess being configured to either directly receive a growing-medium plug or to receive the plug within an insert. These inserts are generally made of a plastic material and receive the growing medium plugs within its walls. The inserts are then fitted within the demarcated recesses of the tray in a modular configuration.

[0010] With non-modular configuration propagation trays, when sufficient root growth has occurred within the plug, the growing-medium plug is simply removed from each “pocket” or recess within the base of the tray and planted or potted on. Whereas, with modular configuration propagation trays having recesses each configured to hold a growing-medium plug comprising a plant propagate encased in an insert, the growing-medium plugs are removed from the recesses in the base of the tray and, following removal of the plugs from each insert, the plugs are planted or potted on.

[0011] A prevalent disadvantage of using a modular tray and insert configuration is that end-users neglect to collect the inserts after use and these remain in the field after planting the plugs resulting in increased expenses when propagating subsequent seedlings, as well as environmental concerns when plastic inserts are left outside causing environmental pollution.

[0012] More recent modular propagation tray systems have replaced plastic inserts with biodegradable sleeves. The entire unit, that is the growing medium plug and biodegradable sleeve, is then removed from the recesses within the base of the tray and planted on, thus, reducing expenses of end-users and reducing plastic pollution when planting the plugs on. However, these systems still require a user to remove the entire plug from a recess which may damage the plug in the process.

[0013] The raw material and texture of the growing medium is determined by the limitations of the manufacturing process such as the suitability of the medium to fill the sleeve, the compaction rate and the ease of slicing the plug into segments. Current tray systems for propagating growingmedium plugs do not provide adequate growing conditions resulting in reduced air-fill porosity (AFP) and overly extended moisture retention of the growing medium, which in turn results in substandard plant production. AFP is the amount of air in a given volume of growing medium.

[0014] Current plug propagation methods are known to have several disadvantages. A variable moisture differential often occurs across a plant plug body when using known plug propagation tray configurations as a result of the exposure of a sizeable portion of the plug above the surface of the tray. Exposure of a portion of the plug has been shown to cause drying out in the exposed portion at a faster rate than in the concealed portion of the plug, causing a moisture differential and consequently negatively affecting plant production. The moisture differential caused by current plug propagation solutions can furthermore cause a separation between the wet and dry sections of the plug. The wet material of the plug, which aggregates at the bottom of the recess in the tray falls away or separates from the dry material, which can be found at the top of the plug, when the plug is removed from the tray. This separation between the wet and the dry material causes a fissure. A fissure is a physical barrier and prevents root penetration from the top to the bottom of the plug. This results in a sizeable portion of the plug being devoid of roots.

[0015] A majority of the growing mediums used in typical plug propagation systems is sphagnum peat moss. Sphagnum peat moss is partially decomposed sphagnum moss. Its large cell structure enables it to absorb air and water like a sponge. A negative characteristic of sphagnum peat moss is that the material becomes hydrophobic when desiccated or dried out. This results in a “cap” forming on the top of the plug which causes irrigation water to run off the cap and down the outside of the plug. Thus, only the bottom of the plug is wettened where it makes contact with the wall of the tray. The roots of the seedling within the plug compensate by finding moisture on the outside of the plug where excess growing medium and standing water often collects, that is between the plug and the wall of existing propagation trays. The roots of these seedlings then penetrate the bottom of the plug where there is adequate moisture, leaving the centre of the plug sparse. Furthermore, these external roots are exposed from the plug making them highly susceptible to damage and desiccation which is undesirable in any plant propagation system.

[0016] A further disadvantage of current propagation tray solutions is compaction of the growing medium caused by the inability of the plug to expand due to the inflexibility of the insert, sleeve or external walls of the recesses within the base of the tray. The roots from cuttings or seedlings proliferate and compact the growing medium, which then reduces the AFP to a suboptimal level. The water retention capacity (WRC) is inversely proportional to the AFP. Consequently, as the AFP decreases, the WRC increases which results in an oxygen deficit. It is generally known that plant roots need oxygen to respire.

[0017] The oxygen deficit caused by the low AFP and high WRC causes the roots of the seedling to escape the sleeve to a region with a higher oxygen to water ratio. Such a region is between the tray cavity wall and the outside of the plug or similarly, in the excess growing-medium between the plug and the tray or insert. The humidity in the confine between the plug and the wall of the tray is high enough (> 75% humidity) to prevent desiccation and support growth of the roots. The restricted airflow between the wall of the tray and the moist plug encourages the accumulation of moisture in this recess. The resultant high humidity prevents air-pruning of the protruding roots, enabling them to grow and proliferate outside of the plug and in the recess between the wall of the tray and the plug. This causes the roots to develop a considerable bulk around the plug but grow sparsely within the plug. External roots will grow in circles between the bottom of the tray cavity and the outside of the plug, giving rise to root-spiraling and bench-rooting, both common and unacceptable root problems in the nursery industry. The bulk of the roots are external to the plug compared to the internal roots in the plug, producing a seedling that is highly susceptible to desiccation and mechanical root damage.

[0018] The irrigation efficiency of the current paper pot plugs in the conventional tray is low because of the design flaw in the tray. There is a large gap between the plug and the wall of the tray. The gap, intended to encourage air pruning of the roots, creates a conduit for conveying irrigation water past the plug and beneath the tray. Furthermore, the irrigation target is restricted by all the plastic surrounding the plug. Significantly more irrigation water is required to hydrate the plug because the restricted exposure of the plug to intercept the irrigation water emitted by the microsprinklers.

[0019] The invention disclosed herein aims to address the disadvantages of current propagation tray solutions, at least to some extent.

[0020] The preceding discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge in the art as at the priority date of the application.

[0021] SUMMARY OF THE INVENTION

[0022] According to an aspect of the present invention there is provided a propagation tray comprising a base having a two-dimensional array of spaced-apart spikes extending from the base. Each spike comprises a central axis with a plurality of curved longitudinal fins arranged about the central axis and extending radially therefrom. A side profile of each fin forms a curved web between the central axis of the spike and the base. In use, the spikes act as support members that receive and support at least a portion of a growing medium plug.

[0023] The curve of the web may be mathematically modelled as approximating the shape of y = Acot Bx) for (0 < % < where the y-axis is defined by the central axis of the spike, and the x-axis is defined by the surface of the base, with the origin coordinate (0,0) being located where the central axis of the spike meets the surface of the base. A and B are multipliers that determine the height and width of the web, respectively. The tip of the spike is therefore near x = 0. It is emphasised that this is merely an approximation of the shape of the web.

[0024] These features may enable the fins to be thinner or more tapered near the tip of the spike (i.e. the distal end of the spike) than near the base. This may enable the spike to easily enter a growing medium plug, when the plug is stuck onto the spike, due to the thinner tip, but the fins widening towards the base ensures a secure fit of the plug on the fins. When penetrating the growing medium plug the spike creates a cavity in the plug, with the shape of the spike creating a complementary-shaped cavity, the shape of which may reduce interference of the plant propagation (root formation, etc.) within the plug.

[0025] The spacing between spikes may vary in different embodiments of the tray depending on factors like the size of the growing-medium plugs they are intended to be used with which, in turn, may depend on the type of plant being propagated. The spikes may be spaced so as to provide adequate spacing between adjacent plugs (in use) to prevent contact between adjacent plugs.

[0026] The tray may further comprise sidewalls. A first set of the sidewalls may have a first set of vertical channels that are spaced apart on each sidewall of the first set of sidewalls in a first pattern. A second set of the sidewalls may have a second set of vertical channels that are spaced apart on each sidewall of the second set of sidewalls in a second pattern different to the first pattern. Each channel may extend at least along a part of the height of the relevant sidewall. The sidewalls may be sloped so as to enable the tray to be received in a stacked or nested vertical arrangement with a substantially identical tray. An operatively upper end of each of the vertical channels may provide a resting platform located between half the height of the sidewall and an upper edge of the sidewall.

[0027] A “set” in this context, i.e. the context of the sidewalls and the vertical channels, may include a singleton set, i.e. consisting of only one element, or a plurality of elements.

[0028] The stacked and nested tray arrangements are similar in that they are both vertical storage arrangements. However, in the nested arrangement the trays fit deeper into each other (e.g. for storage or transport of empty trays) and in the stacked arrangement the trays fit shallower into each other (e.g. for storage or transport of filled or partially filled trays).

[0029] The first and second set of vertical channels may be configured to allow the tray to be nested with a second, substantially identical tray (i.e. in the nested configuration) if positioned in the same orientation relative to the second tray, i.e. with the first and second set of vertical channels of the tray vertically aligning with that of the second tray. In the nested configuration, the similar vertical channels all being aligned with each other enable the tray to extend deep into the second tray.

[0030] The first and second set of vertical channels may be configured to allow the tray to be stacked on top of a second, substantially identical tray if positioned in a dissimilar orientation relative to the second tray, for example rotated 90° or 180° in the horizontal plane relative to the second tray (i.e. with the first and second vertical channels of the respective trays not in vertical alignment with that of the second tray). In the stacked configuration, the similar vertical channels not being aligned with each other limits the depth that the tray may extend into the second tray due to the base of the upper tray abutting the resting platform defined by the operatively upper ends of the bottom tray’s vertical channels.

[0031] This may minimize the space required for storage or transport of the trays. The resting platforms of the vertical channels may be flat distal (or operatively upper) ends of the vertical channels.

[0032] The spikes may be at least partially hollow. The fins may be arranged such that the spikes have a substantially star-shaped cross-section. The spikes may be arranged such that the cross section of the propagation tray assembly provides substantially U-shaped spaces between adjacent spikes.

[0033] The base may be perforated. The base may include a plurality of apertures dispersed between the spikes in use.

[0034] The base may have a grid of longitudinal and transverse members defining a grid of base drainage apertures. The spikes may be located at intersections of the longitudinal and transverse members.

[0035] In some embodiments the spikes, base and sidewalls may be integrally formed.

[0036] In a further aspect of the invention there is provided a propagation tray assembly that comprises a tray holder. The holder has a resting surface or floor from which sidewalls extend. The assembly further includes one or more propagation trays as described above. The holder is configured to receive the one or more trays on the resting surface

[0037] The sidewalls of the assembly’s holder may include a first set of the sidewalls having a first set of vertical channels that are spaced apart on each sidewall of the first set of sidewalls in a first pattern. The assembly’s holder may further include a second set of the sidewalls having a second set of vertical channels that are spaced apart on each sidewall of the second set of sidewalls in a second pattern different to the first pattern, each channel extending at least along a part of the height of the relevant sidewall. The sidewalls may be sloped so as to enable the holder to be received in a stacked or nested vertical arrangement with a substantially identical holder. An operatively upper end of each of the vertical channels provides a resting platform located between half the height of the sidewall and an upper edge of the sidewall.

[0038] The propagation tray assembly may be formed of a semi-rigid material. The tray assembly may be of a predetermined size for use with an automated growing-medium plug and tray assembly system.

[0039] The holder of the propagation tray assembly may have a resting surface that comprises a grid of longitudinal and transverse members. The longitudinal and transverse members may define a grid of holder drainage apertures that are larger than the base drainage apertures of the one or more trays.

[0040] These features may enable the tray and / or holder to drain. This lends the propagation tray and / or propagation tray assembly to be used particularly well with seedlings, which require adequate drainage.

[0041] According to a further aspect of the present invention there is provided a selection of kits.

[0042] In one embodiment the kit may comprise a propagation tray in accordance with the present invention, as described above, and one or more growing-medium plugs. In another embodiment, the kit may comprise a propagation tray assembly including a holder, one or more (modular) trays, and one or more growing-medium plugs. The holder may be configured for one or more propagation trays according to the present invention configured to be held therein. The plurality of propagation trays may have different arrangements of spikes suitable for a variety of growingmedium plugs containing different plant propagates. As such the holder can accommodate propagation tray assemblies holding a variety of different growing-medium plugs.

[0043] These features may enable the kit to be modular in nature, as the different spikes may be used interchangeably with a universal holder.

[0044] An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In the drawings:

[0046] Figure 1A is a graph of the mathematical equation that approximates the curved shape of a fin of spikes found on the trays of the present disclosure;

[0047] Figure 1B is an overlay of graph axes on a cross-section of a spike to illustrate the resemblance of the curve of the spike with the graph shown in Figure 1 A;

[0048] Figure 2 is a three-dimensional view of an example embodiment of a propagation tray according to aspects of the present disclosure in use with growing medium plugs;

[0049] Figure 3 is a sectional three-dimensional view of the propagation tray of Figure 2;

[0050] Figure 4 is a sectional front view of the propagation tray of Figure 2;

[0051] Figure 5 is a side view of the propagation tray of Figure 2;

[0052] Figure 6 is a top view of the propagation tray of Figure 2;

[0053] Figure 7 is a bottom view of the propagation tray of Figure 2;

[0054] Figure 8 is a three-dimensional view from the top of an example embodiment of a holder for use with the propagation tray of Figure 2 to form a propagation tray assembly;

[0055] Figure 9 is a three-dimensional view from the bottom of the holder of Figure 8;

[0056] Figure 10 is an exploded three-dimensional view of a plurality of the propagation trays of Figure 2 and the holder of Figure 8, together forming a propagation tray assembly;

[0057] Figure 11 is a three-dimensional view of a propagation tray assembly with the parts of Figure 10;

[0058] Figure 12 is an exploded three-dimensional view of the holder of Figure 8 and the propagation tray assembly of Figure 11 ;

[0059] Figure 13 is the holder and tray assembly of Figure 12 shown in a nested condition and a stacked condition, respectively;

[0060] Figure 14 is a three-dimensional view of a second example embodiment of a propagation tray according to aspects of the present disclosure;

[0061] Figure 15 is a three-dimensional view of the propagation tray of Figure 14 in use with growing medium plugs;

[0062] Figure 16 is a top view of the propagation tray of Figure 14;

[0063] Figure 17 is a bottom view of the propagation tray of Figure 14;

[0064] Figure 18 is a section view of the propagation tray of Figure 14 taken longitudinally through the centre of the tray;

[0065] Figure 19 is the same section view of Figure 18, showing the tray in use with growing medium plugs;

[0066] Figure 20 is a section view similar to that of Figure 18, showing two trays in a stacked configuration;

[0067] Figure 21 is a three-dimensional view of the stacked configuration of Figure 20;

[0068] Figure 22 is a first side view of the tray of Figure 14;

[0069] Figure 23 is a second side view of the tray of Figure 14;

[0070] Figure 24 is a third side view of the tray of Figure 14; and

[0071] Figure 25 is a fourth side view of the tray of Figure 14.

[0072] DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

[0073] Exemplary embodiments of a propagation tray, propagation tray assemblies, and kits therefor are described below.

[0074] The propagation trays and propagation tray assemblies may be referred to collectively herein as “propagation trays” or “trays”, where the context enables the reference to apply to both such embodiments.

[0075] The propagation tray and propagation tray assembly find particular application in the propagation of seedlings, cuttings, seeds or similar plant propagating material using growing-medium plug propagation methods. The plant propagating material and root media or growing media may be encased in a sleeve to form said growing-medium plug which is then cultivated on spikes or support members of the propagation tray assembly. Following adequate root proliferation, the growing-medium plugs are removed from the propagation tray or propagation tray assembly, as the case may be, and transplanted or potted on. In particular, the propagation tray and propagation tray assembly may provide optimal propagation conditions for seedlings such as tree seedlings as the spike tray configuration may prevent excess growing medium, excess moisture, or standing water accumulating around or outside of the growing-medium plug thereby facilitating root proliferation primarily within the plug.

[0076] The propagation tray comprises a base having a two-dimensional array (or a grid) of spacedapart support members or spikes extending from the base. Each spike comprises a central axis with a plurality of curved longitudinal fins (or wings) arranged about the central axis and extending radially therefrom. This is comparable to the wings or “flights” on a playing dart. A side profile of each fin forms a curved web between the central axis of the spike and the base. The shape of the curved web is analogous to the web space or thenar web space between the index finger and thumb when the index finger and thumb are held in an “L”-shape.

[0077] As illustrated in Figure 1A, the curved side profile of the fins on the spikes, i.e. the curved web of each fin, may be mathematically modelled as approximating the shape of y = Acot Bx) in which the x-axis is formed by an upper surface of the base, and the y-axis formed by the central axis of the spike. This is further illustrated in Figure 1 B, which shows the aforementioned curve superimposed over a cross-section of a spike according to aspects of the present invention, and which is described in more detail below. The diameter of the growing medium plugs may typically range between 30mm and 60mm. The widest part of the fins (i.e. where it meets the surface of the base) must therefore have a radius (radial length from central axis) slightly smaller than the radius of the plug with which it is intended to be used. The radial length of the fin may therefore be between 2mm and 30mm, preferably between 2mm and 15mm, optionally between 5mm and 15mm. With the curved side profile of the fins approximating the shape of y = Acot Bx) and with the curve crossing the x-axis (corresponding to where the fin meets the surface of the base) at — the parameter B may therefore typically be between 0.785 and 0.052, preferably between 0.785 and 0.105, optionally between 0.314 and 0.105 (with the x-axis being scaled in mm). The parameter A may typically be 0.1 < A < 10 . More preferably, the parameter A may typically be 0.1 < A < 5 A higher value for A would produce a more gradual curve, whereas a smaller value of A would produce a more pronounced curve.

[0078] As shown in Figure 1 B, the spike (1) extends from a base (2). The y-axis is defined by the central axis of the spike (1), and the x-axis is defined by the upper surface of the base (2), with the origin coordinate (0,0) being located where the central axis of the spike meets the surface of the base

[0079] (2). A and B in the equation above are multipliers that determine the height and width of the web

[0080] (3), respectively. The tip (4) of the spike is therefore nearx = 0. It is emphasised that this is merely an approximation of the shape of the web. The uppermost tip (4) of the spike may be more sharply angled, deviating from the mathematical approximation (which stretches along the y-axis to infinity).

[0081] These features may enable the fins to be thinner or more tapered near the tip of the spike (i.e. the distal end of the spike) than near the base where the sloped or curved portion of the fin (i.e. the web of the fin) is located. This may enable the spike to easily enter a growing medium plug, when the plug is stuck onto the spike, due to the thinner tip, but the fins widening towards the base ensures a secure fit of the plug on the fin. When penetrating the growing medium plug the spike creates a cavity in the plug, with the shape of the spike creating a complementary-shaped cavity, the shape of which may reduce interference of the plant propagation (root formation, etc.) within the plug.

[0082] The spikes may be at least partially hollow. This may limit the amount of material used for the tray, and thus also the weight of the tray. In some embodiments, the plurality of fins extending radially from the spikes may be between 3 and 5 in number (inclusive). In some embodiments, the number of fins arranged about the central axis of, and extending radially from the spike, may be 4 in total on each spike. The fins may be angularly arranged about the central axis of the spike in equal angular intervals, such that the spikes may have a star-shaped cross section (taken in a horizontal plane through the spike). The spikes may be arranged such that the cross section of the propagation tray and / or propagation tray assembly (takin in a vertical plane) provides substantially U-shaped spaces between adjacent spikes.

[0083] Exemplary embodiments of a tray are further described below.

[0084] Referring to Figures 2 to 7, an example embodiment of a propagation tray (100) is shown. The tray includes a base (101) having a plurality of spaced-apart spikes (102) extending in an operatively upward direction from the base (101). More particularly, spikes (102) are provided on the base (101) in a two-dimensional array of spaced-apart spikes (102).

[0085] The shape of the spike is as is explained above with reference to Figure 1 B, and comprises a central axis with a plurality of curved longitudinal fins arranged about the central axis and extending radially therefrom.

[0086] The spikes (102) are arranged for receiving and supporting growing medium plugs (110) in use. The side of the base (101) from which the spikes (102) protrude may be the operatively upper or top side, or surface (103) of the base. An opposing side (104) of the base (which may be the bottom side in use) is configured such that the tray assembly may be placed on a surface, such as a table, or the floor, to allow a user or machine to place growing-medium plugs (110) onto the spikes (102). In some embodiments or use cases, more than one spike (102) may be used to secure a single growing-medium plug.

[0087] The plurality of spikes (102) may differ in number between propagation trays (100) such that different trays (100) are suitable to hold different types of growing-medium plugs containing different plant propagates. A tray having more, closely spaced spikes such as a 4x4 arrangement of spikes on the base is suitable to accommodate smaller growing-medium plugs which require little space therebetween, for example growing-medium plugs containing chilli or herb seeds. Another tray may have a 2x2 arrangement of spikes on the same sized base which is suitable to hold larger growing-medium plugs which require more space therebetween, for example growingmedium plugs containing larger bulbs or tree seedlings.

[0088] Alternatively, or additionally, the base (101) may be configured to support the plurality of spikes having the same dimensions or different dimensions to accommodate variably sized growing- medium plugs. For example, some spikes may be shorter and / or thinner to accommodate a small seedling in a growing medium plug such as an herb seedling, while other spikes may be longer and / or thicker to accommodate a larger growing medium plug containing a larger plant propagate such as an avocado seed. The dimensions (or footprints) of the different spikes may be configured so that they can be used interchangeably with a universal holder, making the propagation system modular in nature.

[0089] Each spike (102) is elongate in shape, having a distal end (108) (i.e. distally to the base) and a proximal end (109) relative to the base in use. Each spike has a tapered portion or tip (111) at the distal end (108) thereof. The tip (111) may be configured and operable to pierce a growingmedium plug placed thereon.

[0090] As also explained above with reference to Figure 1 B, each spike (102) has a plurality of radially extending fins (113), extending radially from a central (operatively vertical) axis of the spike. In the present embodiment, each spike has four such fins (113) extending from the central axis of the spike and are arranged at equal angular intervals about the central axis. Each fin (113) may have a sloped or curved portion, referred to above as a curved web section (112) extending towards the base at the proximal end (109) of the spike. The sloped portion or curved web (112) at the proximal end (109) of each spike (102) may provide a natural stopping point or an indicator of where to stop when penetrating a growing-medium plug (110) to ensure that the plug is spaced apart or raised from the base (101) to encourage the air pruning of roots and water drainage.

[0091] The sloped portion may be gradually sloped as illustrated in the Figures or may be steeply curved or angular, or any other suitable shape to provide a stopping point for a growing-medium plug while allowing water and growing or rooting medium to run off and away from the growing-medium plug in use. As seen in the cross-section shown in Figure 4, the spikes may be arranged such that the cross section of the propagation tray assembly provides substantially U-shaped spaces (116) between adjacent spikes.

[0092] One or more of the spikes (102) may be integrally formed with the base. Each of the plurality of spikes (102) may be fixed to the base (101) at an end of the spikes (102) proximal to the base (101).

[0093] The base (101) may be perforated, or include a plurality of base apertures (106) which may prevent water from collecting on a top surface (103) of the base. The base apertures (106) may extend through the base (101) from a top (103) to a bottom (104) surface of the base to allow passage of water and excess growing or rooting medium therethrough. The base (101) includes a grid of longitudinal (117) and transverse members (118) defining a grid of base drainage apertures (106) therebetween. The spikes (102) are provided at intersections (119) of the longitudinal and transverse members (117, 118). The intersections (119) may be hollow. This enables irrigation water (or other water) to drain away from the growing-medium plugs (110) as standing water could provide a breeding ground for pests and disease in the crop or could encourage the roots to grow out of the growing-medium plug (110) and through the base (101), and could also cause roots to rot.

[0094] In some embodiments, the apertures (106) may not extend through to the bottom (104) of the base and simply collect water within the base but may extend away from the growing-medium plugs (110). This may, in some embodiments, provide sufficient drainage.

[0095] The base drainage apertures (106) of the present embodiment of the tray (100) are substantially square. However, in other embodiments the base drainage apertures may be circular, square, oval, elongate, hexagonal, or any suitable shape and size to permit water and excess growing medium to pass therethrough and away from the growing-medium plugs (110).

[0096] The propagation tray assembly (100) may be dimensioned so as to allow compliance and complementary use with automated systems for propagation and use with predetermined spaces available on shelves or other surfaces within a nursery or another storage and / or manufacturing facility. The dimensions of the propagation tray assembly (100) may be varied depending on an end-user’s requirements, for example the number of growing-medium plugs (110) required, space limitations within a nursery or on transport vehicles, the size of the growing-medium plugs (110) used, and the like.

[0097] The shape and dimensions of the spikes (102) may be suitable to accommodate the varying shape and dimensions of the growing-medium plugs (110). The shape and dimensions of the growing-medium plug (110) is determined by, amongst other factors, the plant variety, manufacturing budget, growing time in the nursery, and the availability of raw materials which may be used by the plant propagate. The growing-medium plug (110) size is generally in conformance with industry standards and may be about 30 to 60 mm in diameter and about 50 to 100 mm in length. The spikes (102) may be of a suitable length and width to accommodate the aforementioned growing-medium plug dimensions. The length of the spike (102) may be a ratio of between about 4:10 and 7.5:10 in relation to the length of the growing-medium plug (110). In other words, the length of each spike (102) may be between about 40% to 75% of the total length of the relevant growing-medium plug. The radial length of the fin (113) where it meets the upper surface of the base (101), i.e. the distance from the central axis of the spike to where the curve of the fin crosses the upper surface of the base, may be between about 15% and 75% of the radius of the plug (assuming the plug is cylindrical in shape). That is to say that the spikes and their fins may be dimensioned so as to not breach the outer walls of the plugs when mounted onto the spike. The number of spikes provided on the base may be suitable to accommodate a particularly sized growing-medium plug.

[0098] The dimensions of the base (101) may be of a predetermined length and width in compliance with nursery or industry requirements and to allow a user to place the propagation tray assembly (100) on surfaces within a nursery or to transport the propagation tray assembly (100) between the propagating facility and a nursery, or between a nursery and the end destination of the growingmedium plugs and plant propagates. The base thickness may be between about 5 mm and 25 mm, preferably between about 8 and 12mm, most preferably about 10mm.

[0099] The spikes (102) may be pointed or tapered at a distal end thereof relative to the base in use, as illustrated in Figures 1 B to 7. Particularly, the cross section of each spike’s tip may be cross shaped or circular, or any suitable shape to allow the spike (102) to penetrate, receive and support a growing-medium plug (110) when a lower surface of the growing medium plug is pressed against the distal end or tip of the relevant spike such that the spike penetrates the growing medium plug. The spikes (102) receive and support the growing-medium plugs (110) such that the entire growing-medium plug remains exposed, or unconfined, when secured to a spike. The spikes (102) may be spaced apart to at least partially prevent the growing-medium plugs (110) from contacting one another once received and supported by the spikes (102). The growingmedium plugs (110) are further arranged so as not to touch the base (101), or any other component of the propagation tray assembly (100) except the spike (102). This may permit the roots to be air-pruned and to grow within or near the confines of the plug, thereby preventing the roots from becoming pot-bound. Air pruning is a natural process where the root tips dry out and stop growing thereby encouraging the plant to develop more fibrous lateral roots.

[0100] In use, the growing-medium plugs (110) are spaced apart. The spaced apart growing-medium plugs (110) and absence of external walls surrounding each growing-medium plug (110) inhibits the growing medium from collecting next to or in the immediate proximity of the growing-medium plug (110). Preventing the accumulation of excess growing media around the growing medium plugs may discourage or inhibit the roots from growing outside of the growing-medium plug (110) and therefore contain the root growth within the growing-medium plug (110). Furthermore, the spaced apart growing-medium plugs (110) and absence of external walls surrounding each growing-medium plug (110) may also inhibit water from collecting in the growing-medium plug. This may prevent the growing-medium plug (110) from being subjected to variable moisture content as the entire growing-medium plug (110) is exposed, allowing for even moisture loss across the entire growing-medium plug (110) body. Thus, the growing-medium plug (110) may dry evenly and entirely from the outside in, which in turn may force the plant propagate roots to grow inside the growing-medium plug (110).

[0101] In use, the growing-medium plug (110) including the plant propagate, that is the seed, seedling, cutting or any other suitable plant propagation material within a rooting or growing medium, such as synthetic, organic, or combination material, is encased in a biodegradable sleeve which is secured, pressed or placed onto the spike (102) manually by a user or a machine. The spike (102) penetrates the growing-medium plug (110) at an operatively lower end of the growing-medium plug (110) which will, following penetration, be situated near the first or operatively top side (103) of the base (101). The spike (102) may not fully or completely penetrate the growing-medium plug (110) so as not to interfere with the plant propagate within the growing-medium plug (110). Generally, the plant propagate is situated at an operatively upper part of the growing-medium plug (110). The length of the spike (102) may be predetermined to correspond to the size of the growing-medium plug (110) and vice versa, so as to prevent the spike (102) from dislodging the plant propagate, as discussed above.

[0102] Expansion of the growing-medium plug (110) is not restricted because the growing-medium plug (110) is not contained within a rigid insert, recess within the base, or other inflexible formation. As such, the growing-medium plug may freely expand and contract as required to facilitate optimal growing conditions for the plant propagate. Marginal expansion is required to allow for root proliferation and prevent an oxygen deficit in the root medium. Thus, the unrestricted condition of the growing-medium plug supported on a spike may prevent an oxygen deficit in the root medium which can impede root development and negatively impact seedling growth.

[0103] The spike (102) is configured to create a cavity or internal aperture within an operatively central region of the growing-medium plug (110). The cavity may be configured such that it does not interfere with the plant propagate of the growing-medium plug (110). The cavity created in the growing-medium plug (110) may encourage the fibrous roots of the plant propagate to grow through the centre, that is through and along the cavity, instead of on the outside of the growingmedium plug (110). The cavity in the growing-medium plug (110) created by the spike (102) in use may be configured to provide optimal growing conditions such as a suitable amount of water and oxygen or to provide a suitable oxygen to water ratio at the centre of the plug. Optimal growing conditions may in turn ensure root proliferation within and throughout the growing-medium plug (110), that is, root proliferation from the inside out, and consequently prevent root proliferation outside of and around the growing-medium plug (110). Furthermore, exposure of the entire growing-medium plug (110) body when supported on the spikes (102) may provide an effective air-pruning or root-pruning effect which may further prevent plant propagate roots from escaping the growing-medium plug (110) or growing in undesirable areas, such as around or outside the growing-medium plug (110). The cavity may also encourage air circulation and even loss of moisture from within a centre of the growing-medium plug (110).

[0104] A user (or a machine) may, once a plant propagate has sufficiently rooted in a growing-medium plug, remove from the spike (102) the relevant growing-medium plug (110) to be potted on or planted on, that is re-potted or planted in a domestic garden, or field or tunnel for agricultural or forestry industrial use. The disclosed configuration wherein the growing-medium plug (110) is substantially or completely exposed or accessible on the spike (102) may allow a handler or nurseryman to grasp the entire plug during transplanting or grading of the seedlings in the propagation, growing, or rooting phase. This ease of access ensures the root or growing medium within the sleeve does not part due to the creation of a fissure of the growing medium within the plug upon removal from the spike (102) which may impede root growth due to the loss of root or growing medium.

[0105] The propagation tray assembly (100), including its components, may be manufactured by an injection moulding process, three-dimensional printing, CNC machining, vacuum forming, twinsheet forming, compression moulding and the like. Suitable materials may include a wide range of polymers. Examples include, but are not limited to, Polypropylene (PP), Acrylonitrile Butadiene Styrene (ABS), Polyethylene (PE) (LDPE, HDPE), Polyvinyl Chloride (PVC), and the like.

[0106] Figures 10 to 13 show an example embodiment of a propagation tray assembly (150). The propagation tray assembly (150) comprises a tray holder (130), shown on its own in Figures 8 and 9, and one or more propagation trays (100) with the holder (130) being configured to receive the one or more trays on the resting surface. Figures 11 to 13 show the holder (130) and one or more propagation trays (100) assembled together, forming the propagation tray assembly (150).

[0107] The holder may include a floor or resting surface (131) and a plurality of sidewalls (132) extending operatively upwards from the resting surface (131). The resting surface (131) with or without the sidewalls (132) may define one or more receiving zones (133) each configured to receive and support the base (101) of a propagation tray (100) provided thereon in use. The resting surface (131) comprises a grid of longitudinal and transverse members (140) defining a grid of holder drainage apertures (142), coinciding with the receiving zones (133), that are larger than the base drainage apertures (106) of the one or more trays (100).

[0108] Referring to Figure 10, the present embodiment of the holder (130) includes a resting surface (131) defining eight receiving zones coinciding (133) with holder drainage apertures (142). In this embodiment, the holder (130) and trays (100) are dimensioned so that the holder (130) can hold eight propagation trays (100) in a 2x4 two-dimensional array. This embodiment of the holder (130) has eight receiving zones (133) and can hold eight propagation trays (100) (trays with a 4x4 spike arrangement). Such tray assemblies may be suitable to hold smaller growing-medium plugs which require little space therebetween, for example growing-medium plugs containing chili or herb seeds.

[0109] In use cases where the holder (130) is used with other embodiments of trays (i.e. with different dimensions and spike arrangements to the tray (100) described above), the receiving zones (133) in the holder (130) may hold different configurations of trays. Other embodiments of holders may similarly be sized and configured to hold different arrangements of the embodiment of the tray (100) described above. Similarly, the same holder (130) may also hold another four propagation tray assemblies (100) each, for example, having a 2x2 arrangement of spikes which are suitable to hold larger growing-medium plugs which require more space therebetween, for example growing-medium plugs containing larger bulbs or tree seedlings. In general, the holder is configured to accommodate a propagation tray in each receiving zone, each propagation tray optionally having a different arrangement of spikes (and different spacings between spikes) such that growing-medium plugs with different plant propagates may be handled, stored and / or transported together in the same holder.

[0110] The holder (130) makes handling, transport, and storage of the trays (100) more practical.

[0111] In this regard, the sidewalls (132) of the holder may include a cooperating arrangement configured to allow a first holder (130) to be stacked on top of a second holder (130) when the first holder is orientated relative to the second holder in a first orientation. Additionally, or alternatively, the cooperating arrangement may be configured to allow a first holder to be nested within a second holder when the first holder is orientated relative to the second holder in a second orientation. The sidewalls of the holder are sloped so as to enable or ease the holder to be received in a stacked or nested vertical arrangement with a substantially identical holder. The stacked and nested tray arrangements are similar in that they are both vertical storage arrangements. However, in the nested arrangement the trays fit deeper into each other (e.g. for storage or transport of empty trays) and in the stacked arrangement the trays fit shallower into each other (e.g. for storage or transport of filled or partially filled trays).

[0112] As perhaps best illustrated in Figure 12, the holder (130) has sidewalls that include a first set of sidewalls having a first set of vertical channels that are spaced apart on each sidewall of the first set of sidewalls in a first pattern. This is embodied in the holder (130) in that one of the long sidewalls (143) of the rectangularly-shaped holder (i.e. the first set of sidewalls) has four vertical channels (135) (the first set of vertical channels) that are spaced apart on the relevant sidewall in a first pattern (i.e. the four vertical channels spaced apart). This is also embodied in the holder

[0113] (130) in that one of the short sidewalls (146) of the rectangularly-shaped holder (i.e. the first set of sidewalls) has two vertical channels (138) (the first set of vertical channels) that are spaced apart on the relevant sidewall in a first pattern (i.e. the two vertical channels spaced apart). In other words, the first set of sidewalls and first set of vertical channels may be provided by the sidewall (143) having the four vertical channels (135), or may be provided by the sidewall (146) having the two vertical channels (138), or may be provided by both the long sidewall (143) and the short sidewall (146) providing both the four vertical channels (135) and the two vertical channels (138), respectively.

[0114] The holder (130) also has a second set of sidewalls having a second set of vertical channels that are spaced apart on each sidewall of the second set of sidewalls in a second pattern different to the first pattern. This is embodied in the holder (130) in that the other one of the long sidewalls (144) of the rectangularly-shaped holder (i.e. the second set of sidewalls) has three vertical channels (134) (the second set of vertical channels) that are spaced apart on the relevant sidewall in a second pattern (i.e. the three vertical channels spaced apart), the two patterns being different. In addition or alternatively, the second set of vertical channels is provided by one vertical channel (137) provided on the short sidewall (147) (i.e. the second set of sidewalls) opposing the other short sidewall (146) of the rectangularly-shaped holder. In other words, the second set of sidewalls and second set of vertical channels may be provided by the sidewall (144) having the three vertical channels (134), or may be provided by the sidewall (147) having the one vertical channel (137), or may be provided by both the long sidewall (144) and the short sidewall (147) providing both the three vertical channels (134) and the one vertical channel (137), respectively.

[0115] As explained above, a “set” in this context, i.e. the context of the sidewalls and the vertical channels, may include a singleton set, i.e. consisting of only one element, as is the case here. The first set of sidewalls includes only the one, long, sidewall (143). Similarly, the second set of sidewalls includes only the other of the long sidewalls (144).

[0116] Each vertical channel (135, 134) extends at least along a part of the height of the relevant sidewall (143, 144) and terminates at between half the height of the relevant sidewall and an upper edge of the sidewall. In the present embodiment, the vertical channels extend from the resting surface

[0117] (131) (or the bottom of the holder) to between about 70% and 80% of the height of the sidewall. Where the vertical channel (135, 134) terminates, it provides a resting platform (136). The resting platforms (136) of the vertical channels (135, 134) may be substantially flat distal (or operatively upper) ends of the vertical channels. Figure 13 shows three holders (130) in vertically stacked and nested configurations. The uppermost holder will be referenced as (130-1). The second, middle holder will be referenced as (130-2), and the third, bottom holder as (130-3).

[0118] The top and middle trays (130-1 , 130-2) are arranged in a stacked configuration with each other, in which the trays are in a dissimilar orientation to each other. More particularly, the dissimilar orientation is 180° in the horizontal plane relative to each other. In the stacked configuration, the first set of vertical channels (135) and the second set of vertical channels (134) are misaligned with each other. This prevents the top tray (130-1) from fitting into the middle tray (130-2) in the deeper nested arrangement, because the bottom of the tray (the resting surface (131)) comes to rest on the flat distal ends (136) of the vertical channels of the middle tray (130-2). This may be particularly advantageous for storage or transportation of filled holders (130), i.e. holders having trays (100) in them. The space may be sufficient to allow the stacked holders to hold tray assemblies (100) with spikes supporting growing-medium plugs thereon without damage to the growing medium plugs or the plant propagates extending therefrom. As such, many growingmedium plugs supported on many tray assemblies may be easily transported or stored in their respective holders to maximize efficient use of space.

[0119] The middle and bottom trays (130-2, 130-3) are arranged in a deeper, nested configuration with each other, in which the trays are in a similar horizontal orientation to each other, i.e. with the first set of vertical channels (135) of the two trays (130-2, 130-3) vertically aligned with one another, and similarly with the second set of vertical channels (134) of the two trays (130-2, 130-3) vertically aligned with one another. This alignment enables the middle tray (130-2) to fit deeper into the bottom tray (130-3). This may be particularly advantageous for storage and shipping of empty holders.

[0120] The present embodiment of the holder is movable between first and second orientations by rotating the holder 180 degrees. However, in other embodiments, the holder may be configured to allow movement between the first and second orientations by rotation of the holder by 90 degrees or any other suitable amount of rotation depending on the position of the cooperating arrangement and the shape of the holder.

[0121] In the present embodiment of the holder (130), the first and second vertical channels (135, 134) are concave, inwardly extending vertical channels. In other embodiments, the vertical channels may be convex, outwardly extending channels.

[0122] The propagation tray assembly according to the present invention provides spaced apart spikes which allow for optimal growth of a growing-medium plug placed thereon due to the exposure of the plug to air and lack of restricting walls hindering a plug’s ability to marginally expand during growth of the propagate therein. When the plugs are ready for transplanting, the tray assembly allows for easy removal of the growing-medium plugs from the spikes with minimal loss of growing medium and damage to the roots of the developing propagate. The spikes are shaped to encourage run-off of excess growing medium and water from the growing medium-plugs and prevent accumulation thereof around the growing-medium plug. This facilitates root proliferation primarily within the plug, leading to stronger and healthier root systems. The holder according to the present invention allows for easy and efficient handling, transport and storage of propagation tray assemblies and the holders themselves due to their nesting and stacking functionalities.

[0123] Figures 14 to 25 illustrate another embodiment of a propagation tray (200) in accordance with the invention. In this embodiment, the spikes (102) are not provided by modular spike trays held in a holder, but are integrally formed with a holder to form a propagation tray with sidewalls. The shape and configuration of the spikes (102) present in this embodiment of the propagation tray (200) may be the same or substantially the same as those present in the embodiment of the tray (100) described above. Their description above is therefore incorporated herein and not repeated for the sake of conciseness.

[0124] Similarly as with the holder described above, the tray (200) has sidewalls that include a first set of sidewalls having a first set of vertical channels that are spaced apart on each sidewall of the first set of sidewalls in a first pattern. This is embodied in the present tray (200) in that one of the long sidewalls (243) of the substantially rectangularly-shaped tray (i.e. the first set of sidewalls) has three vertical channels (235) (the first set of vertical channels) that are spaced apart on the relevant sidewall (243) in a first pattern (i.e. the three vertical channels spaced apart). One of the short sidewalls (246) of the present rectangularly-shaped tray (200) can be considered the first set of sidewalls which in the present embodiment, has a vertical channel (238) which can be considered the first set of vertical channels on its own or in combination with the three vertical channels (235) on the long sidewall (243).

[0125] The tray (200) also has a second set of sidewalls having a second set of vertical channels that are spaced apart on each sidewall of the second set of sidewalls in a second pattern different to the first pattern. This is embodied in the tray (200) in that the other one of the long sidewalls (244) of the rectangularly-shaped holder (i.e. the second set of sidewalls) has two vertical channels (234) (the second set of vertical channels) that are spaced apart on the relevant sidewall in a second pattern (i.e. the two vertical channels spaced apart), the two patterns being different. The other of the short sidewalls (247) of the present rectangularly-shaped tray (200) can be considered the second set of sidewalls which in the present embodiment, has a vertical channel (237) which can be considered the second set of vertical channels on its own or in combination with the two vertical channels (234) on the long sidewall (244). The vertical channel (237) on the short sidewall (247) is provided in a second, different pattern to the vertical channel (238) provided on the short sidewall (246).

[0126] Each vertical channel (235, 234) extends at least along a part of the height of the relevant sidewall (243, 244) and terminates at between half the height of the relevant sidewall and an upper edge of the sidewall. In the present embodiment, the vertical channels (235, 234) extend from a base (231) (or the bottom of the tray) to between about 80% and 90% of the height of the sidewall. Where the vertical channel (235, 234) terminates, it provides a resting platform (236).

[0127] The tray (200) furthermore has strengthening ribs: one rib (251) extending centrally through the cavity of the tray between the two shorter sidewalls (237, 238), and three transverse ribs (252) spaced apart and extending between the longer sidewalls (243, 244). The strengthening ribs (251 , 252) divide the tray (200) into eight spike zones in a 2x4 two-dimensional array configuration.

[0128] Figure 15 shows the tray (200) partially in use with growing-medium plugs (110), with the growingmedium plugs (110) impaled on the spikes (102) in one of the spike zones.

[0129] As is seen more clearly in Figure 16 and 17, the base (231) of the tray (200) includes a grid of longitudinal members (217) and transverse members (218) defining a grid of base drainage apertures (206) therebetween. The spikes (102) are provided at intersections of the longitudinal and transverse members (217, 218). The apertures enable irrigation water (or other water) to drain away from the growing-medium plugs (110) as standing water could provide a breeding ground for pests and disease in the crop or could encourage the roots to grow out of the growingmedium plug (110), and could also cause roots to rot.

[0130] The base drainage apertures (206) of the present embodiment of the tray (200) are substantially square. However, in other embodiments the base drainage apertures may be circular, square, oval, elongate, hexagonal, or any suitable shape and size to permit water and excess growing medium to pass therethrough and away from the growing-medium plugs (110).

[0131] Figure 20 and 21 shows two trays (200) in a vertically nested configuration with each other, in which the trays are in a similar horizontal orientation to each other, i.e. with the first set of vertical channels (135) of the two trays vertically aligned with one another, and similarly with the second set of vertical channels (234) of the two trays vertically aligned with one another. This alignment enables the trays to fit deep into each other. It will be appreciated that the trays (200) can also be placed in the shallower stacked vertical configuration with each other by placing them on top of each but rotated is 180° in the horizontal plane relative to each other. In the stacked configuration, the first set of vertical channels (235) and the second set of vertical channels (234) are misaligned with each other. This prevents the top tray from fitting into the bottom tray as in the deeper nested arrangement, because the base (231) comes to rest on the flat distal ends (236) of the vertical channels of the bottom tray.

[0132] In the present embodiment of the tray (200), the first and second vertical channels (235, 234) are concave, inwardly extending vertical channels. In other embodiments, the vertical channels may be convex, outwardly extending channels.

[0133] The trays, holders, and growing medium plugs may be provided in a variety of different kits. For example, a holder (130) may be provided in a kit with a plurality of trays (100) sufficient to fill the holder (and perhaps with additional spare trays) and optionally along with a plurality of growing medium plugs (110). Trays (200) with integrally-formed spikes may be provided in a kit together with a plurality of growing medium plugs (110).

[0134] The propagation trays and tray assemblies provided by the present invention address a number of problems associated with current plug propagation methods. For example, it addresses the problem of variable moisture differential across a plant plug body when using known plug propagation tray configurations, since the present invention allows the entire growing medium plug to be exposed to air, thereby enabling it to dry out evenly, and to be kept at a much more substantially uniform moisture level throughout the plug in comparison with known methods.

[0135] The trays provided by the present invention may also address the issue of compaction of the growing medium since the growing medium plugs are not confined by inflexible walls. This provides an improved air-fill porosity (AFP) and related water retention capacity (WRC) which, in turn, provides an improved oxygen presence to enable root respiration. The spikes of the propagation tray are spaced such that an air gap is maintained around the plugs thereby promoting air-pruning of the roots and encouraging root growth within the growing medium plugs. Having sufficient oxygen available for the roots to respire also reduces or avoids root-spiraling and bench-rooting, both common and unacceptable root problems in the nursery industry.

[0136] The interception area or irrigation target of the plugs assembled in the tray provided by the present invention is much larger than conventional paper pot trays because there is no plastic obstructing the water emitted by the micro-sprinklers. The irrigation efficiency is therefore greater in the present invention than conventional paper pot trays which has considerable commercial implications. Experimental results were performed between trays (200) according to the present invention and conventional plant propagation trays. At 5 weeks from planting, 20 cuttings were destructively sampled and assessed for root orientation, percentage internal vs external roots, root and shoot dry biomass, and percentage bridging.

[0137] The present invention’s trays (200) outperformed their conventional counterparts with regards to percentage rooting and survival. The increases on such a small scale may have been relatively small, but on a commercial scale this could be financially significant. The trays (200) also demonstrated their ability to air-prune roots with roots in conventional trays being produced externally significantly more. The trays (200) also yielded more root and shoot biomass compared to their conventional counterparts.

[0138] The foregoing description has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure.

[0139] The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

[0140] Finally, throughout the specification and accompanying claims, unless the context requires otherwise, the word ‘comprise’ or variations such as ‘comprises’ or ‘comprising’ will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

CLAIMS:

1. A propagation tray (100) comprising a base (101) having a two-dimensional array of spaced-apart spikes (102) extending from the base, each spike comprising a central axis with a plurality of curved longitudinal fins (113) arranged about the central axis and extending radially therefrom, with a side profile of each fin forming a curved web (112) between the central axis of the spike and the base, wherein, in use, the spikes act as support members that receive and support at least a portion of a growing medium plug (110).

2. The propagation tray (100) as claimed in claim 1 wherein the curve of the web (112) of the side profile of each fin (113) may be mathematically modelled as approximating the shape of y = Acot Bx) for (0 < % < where the y-axis is defined by the central axis of the spike, and the x-axis is defined by the surface (103) of the base (101), with the origin coordinate (0,0) being located where the central axis of the spike meets the surface of the base, and wherein A and B are multipliers that determine the height and width of the web, respectively.

3. The propagation tray (100) as claimed in claim 1 or 2 in which the base comprises a grid of longitudinal (117) and transverse members (118) defining a grid of base drainage apertures (106), with the spikes being located at intersections (119) of the longitudinal and transverse members.

4. The propagation tray (200) as claimed in any one of claims 1 to 3 further comprising sidewalls having: a first set of the sidewalls (243, 246) having a first set of vertical channels (235, 238) that are spaced apart on each sidewall of the first set of sidewalls in a first pattern; and a second set of the sidewalls (244, 247) having a second set of vertical channels (234, 237) that are spaced apart on each sidewall of the second set of sidewalls in a second pattern different to the first pattern, each channel extending at least along a part of the height of the relevant sidewall, wherein the sidewalls are sloped so as to enable the tray to be received in a stacked or nested vertical arrangement with a substantially identical tray,wherein an operatively upper end of each of the vertical channels provides a resting platform located between half the height of the sidewall and an upper edge of the sidewall.

5. The propagation tray (200) as claimed in any one of claims 1 to 4 in which the spikes, base and sidewalls are integrally formed.

6. A propagation tray assembly (150) comprising a tray holder (130), the holder having a resting surface or floor (131) from which sidewalls (132) extend; and one or more trays (100) as claimed in claim 3, with the holder being configured to receive the one or more trays on the resting surface.

7. The propagation tray assembly (150) as claimed in claim 6 in which the sidewalls (132) include: a first set of the sidewalls (143, 146) having a first set of vertical channels (135, 138) that are spaced apart on each sidewall of the first set of sidewalls in a first pattern; and a second set of the sidewalls (144, 147) having a second set of vertical channels (134, 137) that are spaced apart on each sidewall of the second set of sidewalls in a second pattern different to the first pattern, each channel extending at least along a part of the height of the relevant sidewall, wherein the sidewalls are sloped so as to enable the holder to be received in a stacked or nested vertical arrangement with a substantially identical holder, wherein an operatively upper end of each of the vertical channels provides a resting platform located between half the height of the sidewall and an upper edge of the sidewall.

8. The propagation tray assembly (150) as claimed in claim 6 or 7 in which the resting surface (131) of the holder comprises a grid of longitudinal and transverse members (140) defining a grid of holder drainage apertures (142) that are larger than the base drainage apertures (106) of the one or more trays.

9. A kit comprising a propagation tray as claimed in any one of claims 1 to 5 and one or more growing-medium plugs (110).

10. A kit comprising a propagation tray assembly (150) as claimed in any one of claims 6 to 8 including a holder (130), one or more trays (100) as claimed in claim 3, and one or more growing-medium plugs (110).

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