High Temperatures Affect Tomato Production

With the week’s high temperatures, watch for tomato fruit set to be delayed.  This is because pollen dies when temperatures reach 85 degrees F. or higher.  Dead pollen means flowers don’t get pollinated and unfertilized flowers will fall to the ground, resulting in reduced production.

Gardeners often want to know if hand pollination will help get around the problem.  The key thing to keep in mind, however, is that the problem exists because pollen is not surviving the higher temperatures.  Even when pollinators are doing their pollination thing, the movement of dead pollen to flowers is the same as no pollination at all.   Products that aid with fruit set help to a certain extent but will not ensure all flowers will develop into normal tomatoes.

High temperatures can affect fruit set of a wide range of your vegetable plants, including peppers, eggplant, and cucumbers.  Cool evenings help with pollen survival, and hence production, but since we can’t control the weather, waiting for cooler temps is really the answer.

Kathleen Cue
Horticulture Program Coordinator at Nebraska Extension
Kathleen serves as a Horticulture Program Coordinator. She educates people on making smart plant choices to reduce use of fertilizers and pesticides in their landscape which has a positive impact on air, water, soil and environmental quality, property values and people’s pocketbooks. She provides leadership and coordination of the NE Extension in Douglas-Sarpy Counties Master Gardener volunteer programs: the Master Gardener Speakers Bureau, and "Ask the Master Gardener" Consultations.

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