How to grow better tomatoes in hot weather
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.
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.
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”