Knowledgebase
Tomato blossoms browning and dropping off without fruiting #838957
Asked July 04, 2023, 3:44 PM EDT
Lane County Oregon
Expert Response
When flower stems turn yellow and the flowers dry up and fall off exactly as you describe, the phenomenon is known as “blossom drop”. Blossom drop in tomatoes is most commonly due to a lack of pollination, and tomato pollen loses its viability at extreme temperatures – hot or cold. The optimum daytime temperature for producing tomatoes is between 70 and 85 F with a nighttime temperature falling below 72 F. Relative humidity can also affect pollination efficiency and should ideally be between 40 and 70%.
Your tomato plants might need some extra water while the high temperatures continue, but they should return to production when daytime temperatures get back to 85 F or below. If you can provide the plants with some shade during the hottest part of the day that might help maintain their yield.
