QUICK ANSWER
Blossom drop from heat is a common stress response once daytime temperatures push into the high 80s and 90s, or nights stay too warm to give plants a break. It’s not a disease or a sign you did something wrong — pollen becomes less viable at these temperatures, and the plant drops flowers or very young fruit rather than spend energy on something unlikely to develop successfully. Fruit set typically resumes once temperatures ease.
Why Blossom Drop From Heat Happens
Many garden vegetables have a fairly narrow, specific temperature window for successful pollination and fruit set. Once conditions move outside that window, pollen becomes less viable and plants often abort flowers or very young fruit rather than spend energy on something unlikely to develop successfully. It’s a survival response, not a malfunction — the plant is making a calculated decision to protect itself rather than push energy into fruit it likely can’t support right now anyway.
The exact trigger point varies meaningfully by plant, which is worth knowing before assuming a generic heat threshold applies to everything in your garden equally. Tomatoes typically drop flowers once daytime highs exceed 85-90°F or nights stay above 70-75°F. Peppers tolerate slightly more heat, generally holding on until daytime highs pass 95°F. Beans are more heat-sensitive, often dropping flowers once temperatures cross 85°F. Eggplant has the opposite problem at the cool end — it doesn’t set fruit well until nighttime lows exceed 55°F, meaning a cool snap can cause the same blossom drop a heat wave would.
What Makes Blossom Drop From Heat Worse
A few compounding factors turn an ordinary warm stretch into a serious, more prolonged blossom-drop problem than the base temperature alone would cause. High humidity combined with heat can cause pollen to become sticky or “gummy,” making pollination even less likely to succeed even when temperatures alone might have allowed it. Water stress layered directly on top of heat stress makes the problem noticeably worse, since a plant already struggling to manage temperature has even less capacity left to also manage drought. Excess nitrogen fertilizer is a less obvious contributor — pushing the plant toward leafy growth at the expense of flowers and fruit, compounding a drop that heat alone already triggered.
How to Fix Blossom Drop From Heat This Week
• Provide afternoon shade during heat waves — a simple shade cloth over the hottest part of the day can keep flowers viable longer even when the surrounding air is very warm.
• Keep watering consistent and deep, not just frequent — heat stress compounds fast when it’s paired with water stress, and a quick surface sprinkle doesn’t reach deep root systems the way slow, thorough watering does.
• Hold off on nitrogen-heavy fertilizer during a heat wave specifically, since it can push the plant toward more leafy growth right when it should be conserving energy for flowers instead.
• Be patient rather than intervening aggressively. This isn’t a problem pest treatment or emergency feeding fixes, since it’s fundamentally a temperature response — fruit set typically resumes on its own within a week or so once conditions moderate.
For plants that do retain some flowers during a hot stretch, hand-pollination can occasionally help when natural pollination is struggling — gently transferring pollen between flowers with a small brush or cotton swab, ideally in the cooler part of the morning when pollen is more likely to still be viable. This won’t overcome true blossom drop where flowers have already dropped off entirely, but it can help marginal flowers that are still hanging on actually set fruit rather than dropping too.
Related Questions
Should I remove the dropped flowers or fruit?
Not necessary — they’ll decompose naturally, and removing them doesn’t help the plant recover any faster.
Can cold weather cause blossom drop too, not just heat?
Yes — eggplant specifically won’t set fruit well below about 55°F at night, and tomato flowers can also abort below roughly 55°F, so a late cold snap can trigger the same drop a heat wave would, just from the opposite direction.
Will this happen every time it's hot, or only during extreme heat?
Brief warm spells usually don’t trigger it — it’s sustained heat over several days, especially combined with warm nights that never give the plant a break, that causes the most noticeable drop.
