Tomato Blossoms Falling Off? Heat Shock and Watering Are Likely Culprits

The Symptom

Healthy tomato plants in Missouri (near Kansas City) lose blossoms about ¼ inch below the flower. No tiny fruit forms.

Primary Suspect: Heat Stress

When daytime temperatures exceed 90°F (especially over 100°F), tomato plants enter a semi-dormant state to conserve water. Pollen becomes non-viable, and flowers abort. This is a widespread issue in hot summers and often resolves when temperatures cool.

Secondary Factor: Inconsistent Watering

Shallow, frequent watering encourages surface roots that dry out quickly. Deep, infrequent watering (1–2 inches per week) promotes deep roots and steady moisture uptake.

Action Plan

• Mulch heavily (2 inches of straw or shredded leaves) to retain soil moisture.
• Water deeply once or twice a week, not daily.
• Don’t fertilize during heat waves—it stresses roots and foliage.
• Wait it out. Plants typically recover and set fruit once temperatures drop into the 75–90°F range.

Soil Prep for Next Year

Incorporate compost, aged manure, or chicken litter this fall to build nutrient reserves and improve water-holding capacity.