Tomatoes and Dead Flowers

High Temperatures

• Extremely high temperatures—those over 90 degrees Fahrenheit—will cause the flowers on the tomato plant to die and fall off. This is a symptom of the stress that the plant is experiencing. Because of this extra stress, the tomato plants are conserving energy by killing the blossoms on the plant so that they do not produce fruit the plant does not believe it can sustain.

Cool Weather

• Earlier on in the season, or when there is a sudden cold spell in your region, tomato blossoms will die and fall off as a reaction to the cooler temperatures. Early in the season, this is most likely a consequence of cool night temperatures that are below 55 F. In the case of a sudden cold spell, the tomato blossom will fall off as a result of the shock to the plant’s system.

Humidity

• High humidity levels will cause the pollen in the blossoms to become sticky and tacky. As a result, the flowers will not be able to pollinate. In addition to the stress that high humidity causes to tomato plants, the inability to pollinate the flowers will cause the blossoms to die and fall off. Over time, the tomato plant will refresh these blossoms by producing new blossoms.

Pollination

• Tomato flowers are male or female, and their primary purpose is to pollinate and, for the female flowers, produce tomatoes. If the blossoms on a tomato plant remain un-pollinated, the blossoms will fall off over time as they are replaced by newer flowers. In the case of male flowers, the blossoms will fall off even after they have pollinated a female flower.