Why do eggplant flowers drop without fruiting?
Written by
Michael Sullivan
Reviewed by
Prof. Charles Hartman, Ph.D.Many growers are frustrated with the drop of eggplant flowers. The problem generally is related to the day and night temperature shifts. When a plant becomes stressed, it will abort flowers. From my trials in a greenhouse, I found that there would be a 70 percent flower retention rate when the temperature was kept between 75-85°F. If the temperature fluctuates between 60-95°F, the flower retention rate declines to only 30 percent. In general, maintenance of consistent temperature is key.
Temperature Stress
- Day/Night Swings: Over 25°F difference triggers shock
- High Heat: Above 95°F damages pollen viability
- Solution: Use 40% shade cloth during heatwaves
Water Imbalance
- Overwatering: Soggy soil suffocates roots
- Underwatering: Wilted plants abort flowers first
- Solution: Moisture meter checks at 4-inch depth
Pollination Failure
- Humidity Issues: Below 40% dries pollen
- Lack of Bees: Closed greenhouse environments
- Solution: Vibrate flowers daily with electric toothbrush
When it comes to hand-pollination, timing is very important. When pollen is ripe (the middle part of the day), the idea is to mimic bees, and if you would like to do that, you can vibrate the flower stems. I obtain good results with a $5 electric toothbrush (hold it a 1/4 inch from blooms). The toothbrush will transfer pollen better than any brush you can obtain. Record results; for me and my maintenance logs, the vibration resulted in a 3x more fruit set than using the brush.
Patience is required to help plants recover from stress. Once conditions have been addressed, remove flowers that are currently on your plant, thus redirecting the energy into new shoot growth. I use a kelp extract to help generate a level of hormones to encourage new growth. Within 10-14 days you should see new buds materialize, and then keep those flowers in the 70-80 degree F range to protect that growth with row cover.
Read the full article: How to Grow Eggplant: Pro Tips for Big Harvests
