Why Tomato Flowers Drop in Extreme Heat

The Problem: Blossom Drop at 100°F+

Your tomatoes (Beefy Boy, Rassleberry, Park's Whopper) are dropping flowers during a heat wave, while plum tomatoes and peppers set fruit. Plants are healthy, green, and pest-free. The cause is almost certainly heat stress.

Why Heat Causes Blossom Drop

Tomatoes thrive at 75–90°F. Above 95°F, pollen becomes sterile, and plants enter a semi-dormant state to survive. Hybrids are more sensitive than heirlooms. Your peppers tolerate heat better and need less water once blooming, so they continue setting fruit.

Ruling Out Other Causes

• Soil fertility: Your raised beds rich in organic matter (fall leaves added yearly) are likely fertile.
• Pollination: Plum tomatoes and peppers are fruiting, so pollinators are active.
• Watering: Inconsistent watering can cause drop, but your routine is probably adequate.

What to Do Now

1. Don't fertilize. High nitrogen during heat burns roots and foliage.
2. Water deeply and consistently. Aim for 1–2 inches per week, more during heat spikes. Use a soaker hose or drip irrigation.
3. Mulch 2″ deep with straw or shredded leaves to cool roots and retain moisture.
4. Provide afternoon shade with 30% shade cloth if possible.
5. Wait it out. Once temperatures drop below 90°F, plants will recover and set fruit within weeks.

Long-Term Tips

Choose heat-tolerant varieties (e.g., 'Solar Fire', 'Heatmaster') for future plantings. Heirlooms often handle heat better than hybrids.