Why Are My Tomato Flowers Falling Off and Not Setting Fruit?

Temperature is the main trigger

Tomato pollen is fussy about temperature. According to Alabama Cooperative Extension, day temperatures above 85 degrees F or night temperatures above 72 degrees F cause flowers to abort, and temperatures below 55 degrees F can prevent fruit from setting. The longer a heat wave lasts, the longer the plant stays out of production, which is why a stubborn hot spell can leave a stretch of the plant fruitless even though it keeps flowering.

This is a physiological problem, not a pest or disease, so there is nothing to spray. Set usually picks back up on its own once nights cool below the low 70s and days ease out of the high 80s. Providing some afternoon shade during heat waves and keeping soil evenly moist can reduce the number of blossoms lost.

Nitrogen, water, and other contributors

If the weather is mild and flowers are still dropping, look at how you are feeding and watering. Alabama Extension notes that too much nitrogen fertilizer drives excessive vegetative growth and can cause blossom drop or delay flowering, so a plant that is all lush leaves and few fruit may be overfed. Insufficient water or drought stress also causes blossoms to abort; tomatoes generally want about 1 to 1.5 inches of water per week.

Poor pollination from still, muggy air or a shortage of pollinators can add to the problem, since tomato flowers rely on wind and vibration to shed pollen. Because several causes overlap, treat a persistent case as worth investigating step by step, ease off high-nitrogen feed, steady the watering, and if it still does not resolve, your local Extension office can help you narrow it down.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

• Alabama Cooperative Extension - Blossom Drop in Tomato — Flowers often abort when day temperatures exceed 85 F or night temperatures exceed 72 F, and temperatures below 55 F can inhibit fruit set; excess nitrogen and drought stress also cause blossom drop, and tomatoes need about 1 to 1.5 inches of water weekly.
• Clemson HGIC - Why Did My Tomatoes Stop Producing Fruit? — High and low temperature extremes disrupt pollination and cause tomato flowers to drop without setting fruit; fruit set typically resumes when temperatures return to a favorable range.
• University of Maryland Extension - Poor Blossom and Fruit Set of Vegetables — Temperature extremes, excess nitrogen, and moisture stress cause flowers of tomato and other fruiting vegetables to drop without setting fruit.

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