Question
Hi Mike, I thought growing zucchini was foolproof, but my plants are small and the fruit shrivels and turns yellow. I mixed some commercial mushroom manure in the soil before planting. Could I be over-watering, or maybe a soil deficiency? Thanks for your help.
Diana

Answer
The plants are most likely getting too much water, which in turn depletes the soil of phosphorus and iron, two nutrients needed for fruit-bearing vegetables. Zucchini, like all squash, should only receive approximately 1" of water per week. You can supplement more during extremely hot conditions.

Another possibility is that the plants are not being fully pollinated. I always plant bright annuals near my squash to attract bees. Unless the blossoms are fully pollinated, the fruit will shrivel and fall off prematurely. You can also hand-pollinate using a Q-tip or small paint brush if bees are not in the area. Another method is to remove the male flower (the one with the stamen) and rub it against the female blossoms (these always have a small swelling which will form the new squash). Other than bees, I have found this method to be the most full-proof.

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

Regards,

Miek