Green Tomatoes Falling Off? Stress Pests plus Heavy Fruit
Green tomatoes falling off a plant usually trace back to stress from heat or uneven watering, or to insects such as fruitworms feeding on young fruit. University of Arizona Cooperative Extension notes insects, disease, too much or too little water plus sudden temperature change all cause fruit drop. Check the fallen fruit first.
The short answer
Look at the dropped fruit. Neat round holes point to tomato fruitworms. Clean fruit that falls during a hot spell or after dry soil points to stress. University of Arizona Cooperative Extension advises a constant watering routine, since abrupt changes make fruit drop worse. Water deeply once a week in dry weather plus mulch.
How does heat cause tomato fruit drop?
University of Arizona Cooperative Extension notes tomato plants drop blooms when temperatures go above 95F, plus pollination suffers when nights stay at 75F or higher. Its tomato page notes fruit set slows at 90F plus stops at 94F. Iowa State University Extension notes fruit set should pick up again once temperatures moderate.
| Factor | Guideline | Source |
|---|---|---|
| Day heat | Blooms drop above 95F | University of Arizona Cooperative Extension |
| Warm nights | 75F and above hurts pollination | University of Arizona Cooperative Extension |
| Cool nights | Below 55F stops fruit set | University of Arizona Cooperative Extension |
| Water | About 1 to 1.5 inches per week | Iowa State University Extension |
| Ripening | 45 to 55 days after fruit set | Iowa State University Extension |
Source: University of Arizona Cooperative Extension plus Iowa State University Extension.
Why does uneven watering make fruit fall?
University of Arizona Cooperative Extension notes overwatering or starving plants for water during bloom is not advised, plus abrupt changes in watering make blossom plus fruit drop worse. High salt in soil can also cause moisture stress. Iowa State University Extension advises deep weekly watering in dry spells plus mulch to hold soil moisture.
Which pests damage green tomatoes?
Iowa State University Extension notes tomato fruitworms attack green fruit plus leave neat round holes in the side, often spoiling several fruits each. Hornworms feed on leaves plus fruit plus can scar it heavily. Stinkbugs pierce developing fruit, though the damage often shows only as the fruit ripens. Check fruit as it expands.
How to: step by step
- Inspect fallen fruit for holes or chewing.
- Feel the soil a few inches down for moisture.
- Water deeply once a week during dry weather.
- Mulch around the plant to hold moisture.
- Hand pick hornworms plus remove damaged fruit.
- Log day plus night temperatures during the drop.
Troubleshooting
Fruit with round holes drops: fruitworms. Pull damaged fruit plus check the rest often.
Fruit drops in a heat wave: heat stress. Water evenly plus wait for cooler nights.
Fruit drops after a dry spell then a soaking: uneven watering. Water on a fixed weekly routine.
For related reading see the effects of environmental stresses on weed plants, cannabis heat stress plus watering cannabis during drought. Kind Seed Co also stocks cannabis seeds.
Sources
- Flower and fruit drop (Bulletin 16), University of Arizona Cooperative Extension
- Tomato challenges, University of Arizona Cooperative Extension
- Managing tomato diseases, disorders, and pests, Iowa State University Extension and Outreach
FAQ
Can fallen green tomatoes ripen?
Some can. University of Arizona Cooperative Extension notes tomatoes that crack can be picked plus allowed to ripen off the vine, though fruit that cracks while green will likely rot before it ripens. Fruit with blossom end rot usually does not ripen well. Sort fallen fruit plus set aside sound ones to ripen indoors.
Do tomatoes drop fruit in hot weather?
They drop blooms more than formed fruit. University of Arizona Cooperative Extension notes tomato plants drop blooms above 95F plus fruit set stops at 94F or when nights stay over 75F. High heat also limits pollinators. Iowa State University Extension notes fruit set picks up again when temperatures moderate.
Does too much nitrogen cause fruit drop?
It mostly shifts growth to vines. University of Arizona Cooperative Extension notes too much nitrogen grows vines at the expense of fruit for 3 to 4 weeks after feeding. Its bulletin notes a starved plant also sets far fewer blooms plus fruit. Feed moderately at planting plus again once fruit sets.
How often should tomatoes be watered?
Iowa State University Extension notes tomato plants need about 1 to 1.5 inches of water per week during the season. It advises a thorough soaking once every seven days during dry periods plus mulch to hold soil moisture. University of Arizona Cooperative Extension advises a constant watering routine through the whole season.
Can a heavy fruit load cause drop?
It can add to it. University of Arizona Cooperative Extension lists excessive fruit set among the factors behind blossom drop, along with too much pruning, wind plus disease. Its bulletin notes many fruit plants shed a share of small fruit as a natural way of thinning a heavy load. Some loss is normal.
