Protecting Tomatoes in Hot Weather

Hot weather is the enemy of tomatoes. Once temperatures hit 85-90 degrees with nights above 75, plants go into survival mode. They stop producing pollen, blossoms drop off, and growth stalls until things cool down.

The Heat Problem

I live in Southern California where inland temps ramp up hard in summer. If you're on the coast or in the mountains without excessive heat, you can plant normally—skip the heat-tolerant varieties and don't worry about it.

But if you're inland or dealing with real heat, understand this: Surface temperatures next to block walls, stucco walls, cement patios, or even backyard dirt can reach 110-120 degrees when air temperature hits 85-90. That radiant heat is brutal on plants.

1. Mulch with Straw

For tomatoes in the ground or raised beds, put a 3-5 inch layer of straw mulch around plants. This keeps the top layer of soil cooler and prevents excessive water evaporation.

See our complete mulching guide →

2. Use Shade Cloth

Shade helps tomatoes during hot weather—of course it does. Go stand in the sun on a 100-degree day, then move into shade. You don't get sunburned and it feels cooler, doesn't it? Your tomato thinks the same way and won't get sunscald.

Use 50% shade cloth, not 75%. Cut strips 2-3 feet wide by 6 feet tall and hang them on the hot sun side of your cages. Leave them up 24/7 for the rest of the season.

When it gets really hot, many plants stop producing red pigment—tomatoes ripen orange instead of red. If you see tomatoes getting sunburned, pick them early and let them finish ripening inside.

Complete shade cloth installation guide →

3. Keep Roots Moist

Keep that soil moist. Use a moisture meter. You may need to water daily or twice a day in extreme heat.

A mature tomato plant uses 2-3 gallons of water daily even in cooler weather. Hot weather brings more evaporation. Use premium potting soil that holds moisture well—this makes a huge difference.

Pests and diseases thrive in warm soil. Keep plants watered and healthy so they can fight off problems until those tomatoes ripen.

Master proper watering techniques →

4. Plant Heat-Tolerant Varieties

Choose varieties bred for hot weather. They're labeled "heat tolerant" with names like Solar Fire, Heatmaster, Summer Set, and Phoenix (my favorite). These produce tomatoes in 90-degree weather when regular varieties shut down.

Learn more about heat-tolerant varieties →

The Bottom Line

Hot weather doesn't have to end your tomato season. Combine these four strategies—mulch, shade, consistent watering, and heat-tolerant varieties—and your plants will keep producing through the heat.

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Next Steps

Choose heat-tolerant varieties →
Master hot weather watering →
Learn proper mulching →

Dave Freed / The Tomato Guy