Question
I have lots of flowers on my plants. Sometimes you`ll see the beginnings of squash, then the flower drops off. Please let me know what it could be. The plants are in a greenhouse. I live in Princeton, British Columbia.  

Answer
When blossoms or young fruit fall off prematurely, it is usually an indication of one of two problems. Either your plants are not being fully pollinated, or they are receiving too much water.

If you do not have enough bees in the area, you can hand-pollinate the flowers of most vegetables by taking a Q-tip or small paint brush and transferring the pollen from the male flower to the female (the female always has a small fruit on the end). This must be done within one day of the female flower blossoming. However, all you need to do with tomatoes is gently shake the plant every couple of days to improve pollination. To attract more bees, grow sunflowers, marigolds, cosmos, or some other bright annual in the immediate area.

One other possibility is that you are over-fertilizing the plants. Many of today抯 water soluble fertilizers are very high in nitrogen. This results in lush foliage but often at the expense of a smaller harvest. Look for a fertilizer higher in phosphorus and potassium. Many companies now market products formulated especially for tomatoes, which also work great for other fruit-producing vegetables such as squash.

In summary, remember to continue fertilizing with a low nitrogen fertilizer once every other week, and only supplement enough water to ensure a depth of 1.5?per week. Water only once or twice per week but very deeply. Shallow watering always results in poor root development and smaller harvests. Also, be sure to mulch heavily with straw or dried grass clippings around the plants to retain moisture, cool the soil, and to reduce the need for watering.

Good luck, and please write again if I can ever provide assistance.

Regards,

Mike