My tomato plants are full of flowers but no fruit is setting — why?
Tomato flowers drop without setting fruit when night temperatures stay above 70°F or below 55°F — heat at night is the most common cause in mid-summer.
Tomatoes need night temperatures between 55°F and 70°F for pollen to be viable and for fruit to set. Above 70°F at night, pollen becomes sticky and infertile, and flowers drop. This is not a disease, a nutrient problem, or a pollination failure in the usual sense — it's the plant responding to conditions it finds unsuitable for fruit development. In hot climates or during heat waves, entire plantings can drop flowers for 2–3 weeks at a stretch.
Daytime temperatures also matter, but night temperature is the more critical threshold. A day that hits 95°F is stressful; if the night cools to 65°F, pollination can still succeed. A night that stays at 75°F — common during humid heat waves — is more damaging to fruit set than the hot afternoon was.
There's little to do while temperatures are unfavorable except keep the plant healthy, watered, and mulched so it bounces back quickly when conditions improve. Don't fertilize heavily with nitrogen during this period — it pushes vegetative growth rather than helping with fruit set. When temperatures moderate, the plant typically resumes setting within a week.
Some varieties are more heat-tolerant than others. Varieties bred for hot climates — 'Solar Fire,' 'Heatmaster,' 'Florida 91' — can set at higher temperatures than standard varieties. Cherry tomatoes generally set fruit in hotter conditions than beefsteak types. If heat drop is a recurring problem in your climate, variety selection is the most reliable long-term adjustment.
- AnthracnoseSunken, dark circular lesions on ripening fruit, sometimes with salmon-colored spores in the center.
- Blossom DropFlowers fall before setting fruit, often during temperature extremes or after weather stress.
- Blossom End RotDark, sunken, leathery patch on the blossom end of tomato or pepper fruit — a calcium deficiency disorder.
- Gray Mold (Botrytis)Gray-brown fuzzy mold on fruit, flowers, or stems — soft, collapsing tissue beneath the coating in cool, wet conditions.
- Brown Marmorated Stink BugSunken, corky dimples on fruit and pods caused by a mottled brown shield bug feeding through the skin.
- What is that black leathery patch on the bottom of my tomatoes?Blossom end rot is a calcium deficiency at the fruit level, almost always caused by irregular watering rather than a lack of calcium in the soil.
- Why are my tomatoes cracking and splitting?Tomato skin cracks when the fruit expands rapidly after a period of drought — inconsistent watering is almost always the cause, though some varieties are simply crack-prone.
- My tomatoes wilt every afternoon in hot weather — is something wrong?Midday wilt on hot days is often a normal, temporary response to heat load — if plants recover by evening, the roots are functioning and the wilting is a water conservation mechanism, not distress.