Don't Let Hot Weather Ruin Your Tomatoes: Essential Tips 

Hot weather is the enemy of tomatoes.

I live in Southern California and hot temps, especially inland, begin to ramp up as summer comes on. If you are on the coast or in the mountains and do not experience excessive heat, you can plant normally; you don’t need heat tolerant plants or to worry about it getting too hot for your plants.

Hot summer temperatures can bring your tomato plants to a stop. And your plants get especially hot if they are planted next to a block wall, stucco wall, are in containers on a cement patio, etc.

Once temperatures reach 85-90 degrees, surface temperatures radiating back off your cement patio/stucco wall/backyard dirt can reach 110-120 degrees and higher. It can be brutal.

In temperatures of 85 to 90 degrees or so and nights above 75 degrees or so, your tomato plant may go into survival mode until temperatures come back down. Plants may fail to produce pollen or fail to pollinate and the blossoms will simply drop off until the temperatures come back down.

Thermometer reading 123 degrees on patio near tomato plant
123 Degrees is the surface temperature of the patio on a 91 degree day.
C:\Users\Dave\Pictures\1-AAA My Pictures-official 2004 forward\111 Tomatoes---all history\91 degree day 3pm OK\Heroes\P1020024.JPG
Same 91 degree day, under 3 to 5 inches of straw your temperature will be 90 degrees or lower.

Mulch with straw

For tomatoes in the ground or in raised beds, put a 3-5 inch-thick layer of straw mulch around tomato plants. This helps keep the top layer of soil cooler and prevents excessive evaporation of water. See our more detailed post about how to mulch with straw.

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 over into the shade, you don’t get sunburned and feels cooler in the shade, doesn’t it? Your tomato will think just like you and won’t get sunscald/sunburn. Read more about shade cloth in our detailed post.

Water: Keep the roots moist

Keep that soil moist. Use a moisture meter. You may need to water daily or twice a day. Use that premium potting soil that holds a lot of moisture. Hot weather also brings more evaporation. A mature tomato plant will use 2-3 gallons of water daily even in cooler weather. Pests and diseases wake up and thrive in a warm soil. Keep your plants watered and healthy so they can fight off the pests and diseases until those tomatoes ripen.

Heat tolerant tomatoes

Choose a heat tolerant variety. Heat tolerant plants will be labeled as such. They have names like Solar Fire, Heatmaster, Summer Set, Phoenix, etc. My favorite is probably Phoenix. These have been developed to produce tomatoes in 90 degree weather. Read more about heat tolerant tomatoes on in our detailed post.

On the left is Solar Fire and on the right is Heatmaster. Both are heat tolerant tomato plants 

You are welcome to share this information with others—clubs—perhaps share this with your general membership to include those that could not attend the lecture, family, friends, etc. 

Sharing tips helps us be better growers.

Dave Freed / 🍅 “The Tomato Guy”

🍅 Bumper Harvests Made Simple - Discover the secrets to cultivating tomato plants that yield over 100 lbs of fruit!

Expert Advice At Your Fingertips - Get straight-to-the-point guidance on tomato care, including:

  • Pest Control: Keep your tomatoes safe from critters.
  • Disease Prevention: Spot signs early and take action.
  • Optimal Growth Tips: Watering, sunlight, soil, and more!