Blossom end rot is a condition that occurs in some garden vegetables where the end of the growing vegetable where the blossom is suddenly rots, ruining it. This is often caused by calcium deficiency in the soil and/or lack of water. A third possible cause is insufficient natural pollination by insects. This article explains how to manually hand pollinate your zucchini squash to ensure adequate pollination.
Get up early. Zucchini squash flowers are wide open first thing in the morning but close up tightly later in the day. Before you start, take a look at your plants. If you see very few insects buzzing around the flowers you know that your time is about to be well spent.
Find one of the male flowers. Zucchini squash have separate male and female flowers. The male flowers are on long stems.
Pick a male flower. Peel back or break off the petals to expose the pollen-covered stamen. The pollen is messy so try not to get it on your fingers.
Identify the female flowers. These flowers are on short stems that are actually miniature fledgling zucchini.
Carefully rub some pollen from the male flower onto the central pistil of each female flower. You may want to mark the flowers with a piece of ribbon or string tied loosely around the stem so that next time you know which ones you have already pollinated.