The invention discloses a method for planting cucumbers in greenhouses. The method includes fixedly planting 4000-4500 cucumber seeds in each mu of 
greenhouse sheds, timely watering the cucumber seeds, applying 15-20 kilograms 
urea, 10 kilograms of 
potassium sulfate and 15 kilograms of 
diammonium phosphate to cucumber plants in each mu after root cucumbers are expanded, applying fertilizers once whenever the cucumbers are harvested twice in the future, and applying thoroughly decomposed dilute 
manure along with water by 2-3 times in middle and later periods; keeping the 
air humidity suitable for growth and development of the cucumbers in the range from 60% to 80%, and instantly ventilating the 
greenhouse sheds and exhausting 
moisture in the 
greenhouse sheds when the 
humidity of the insides of the tents exceeds 85%; ventilating the greenhouse sheds for 1-2 hours so as to reduce the 
humidity of the greenhouse sheds at night when the 
air temperature ranges from 10 DEG C to 15 DEG C at 
dusk, starting to tie vines when the lengths of the cucumber vines reach 30 centimeters, and moistening flowers by 100-multiplied liquid of fruit retention hormones or spraying the 100-multiplied liquid to the flowers after the cucumbers are born. 1000 kilograms of the thoroughly decomposed dilute 
manure are applied to the cucumber plants in each mu of the greenhouse shed in each procedure. By the aid of the 100-multiplied liquid of the fruit retention hormones, the cucumber sit rate is high, the cucumbers can be retained, and the small cucumbers can be promoted to be quickly expanded. The method has the 
advantage that cucumber and vegetable planting can be quickly developed in a large-scale, low-cost, high-benefit and 
pollution-free manner by the aid of the method.