Eggplant flower drop happens most often due to temperature stress. When temps swing too cold at night or too hot during the day, your plant drops its blooms before fruit can form.
I spent an entire summer puzzled by this problem before I figured out what was going on. My plants looked healthy and made plenty of flowers, but the blooms kept falling off. Then I started checking temps and found the answer.
Night temps below 60°F (16°C) cause big problems for your eggplant flowers. The pollen inside each bloom becomes sticky and will not release the right way in cold air. Without proper pollen transfer, the flower cannot make fruit and drops off the plant.
Hot days cause eggplant flower drop just as much as cold nights do. When temps climb above 90°F (32°C), the pollen dries out and dies before it can do its job. Your plant keeps making blooms but none of them turn into fruit.
Research from the University of Minnesota shows just how narrow the safe range is for eggplants. Temps outside the 60-90°F (16-32°C) range cut fruit set rates way down. Even a few nights below the safe zone can cause a wave of eggplant blossom drop causes you to lose potential fruit.
If your eggplant not fruiting despite having lots of flowers, check your temp first. Use a simple outdoor thermometer near your containers to track highs and lows. You may find that your plants face temp stress you did not know about.
Container growers have a big advantage here since you can move your pots around. On nights when frost threatens, wheel your plants into a garage or covered porch. During heat waves, shift containers to a spot with afternoon shade.
I now keep my eggplant containers on a small cart during peak summer heat. When temps hit the 90s, I roll them to the east side of my house where they get morning sun but escape the harsh afternoon rays. This simple trick stopped most of my flower drop.
Water stress adds to the eggplant blossom drop causes on your plants. Roots that dry out cause the plant to panic and abort its flowers to save energy. Keep soil moist but not soggy by checking pots daily during hot spells.
Hand pollination helps when temps make natural pollination hard. Use a small brush or cotton swab to transfer pollen between flowers during the cool morning hours. Gently dab inside each open bloom to move pollen around by hand.
Low humidity can also keep pollen from doing its job the right way. Mist the air around your plants in the morning if you live in a dry climate. This extra moisture helps pollen stay viable long enough for bees or wind to spread it.
Nutrient problems can trigger flower drop as well, though less often than temp stress. Plants that lack nitrogen or phosphorus may drop blooms to save energy for survival. Keep up with regular feeding every 2-3 weeks to avoid this problem.
Too much nitrogen causes the flip side of this issue in your plants. Heavy feeding pushes lots of leafy growth but few flowers or fruit. If your plant looks lush and green but drops every bloom, cut back on the nitrogen.
Watch your plants each day during bloom time to catch problems early. Move containers when temps go extreme, water on schedule, and hand pollinate if needed. These steps will stop most flower drop and give you a much better harvest.
Read the full article: How to Grow Eggplant in Containers
