How Hot Can Tomatoes Tolerate? Tips for Growing Tomatoes in Warm Weather

Tomatoes are one of the most popular vegetables to grow in home gardens. However high temperatures can make it challenging to get a good tomato harvest. So how hot is too hot for tomatoes?

The Optimal Temperature Range for Tomatoes

Tomatoes thrive in warm conditions, but extreme heat can hamper growth and fruit production The ideal temperature range for tomatoes is 70-85°F during the day and 60-70°F at night. Once temperatures consistently rise above 90°F, tomatoes often struggle

Tomato pollen becomes nonviable at temperatures above 85-90°F. This prevents flowers from being pollinated and setting fruit. Blossom drop and poor fruit set are common problems during hot spells.

Prolonged exposure to temperatures over 100°F can be fatal to tomatoes. Leaves scorch and plants go into survival mode, shutting down fruiting until conditions improve. Nighttime temperatures above 75°F provide no respite for heat-stressed plants.

While tomatoes can withstand short periods of heat, prolonged extreme temperatures take a toll on productivity For best results, aim to keep tomatoes within their optimal temperature range as much as possible

Choosing Heat-Tolerant Tomato Varieties

Certain tomato varieties are more heat-hardy than others. Seek out heat-tolerant cultivars specifically bred to set fruit under high temperatures.

Look for names like Solar Fire, Phoenix, Heatmaster, and Summer Set. Determinate, compact varieties tend to be more heat-tolerant than sprawling indeterminate types.

Cherry tomatoes such as Sun Gold, Husky Cherry Red, and Sweet 100 also hold up well to heat. Larger slicing tomatoes like Celebrity and Better Boy are other good options for warm climates.

Ask local extension services and nurseries for heat-loving tomato recommendations for your area. With a little research, you can find varieties suited to your climate.

Providing Afternoon Shade

Too much sun can overheat tomato plants. Providing some shade, especially in the hottest part of the day, can help tomatoes thrive.

Use shade cloth, awnings, or other structures to block 30-50% of the sunlight from around 1 pm to 5 pm. Allow maximum sun exposure in the morning. Afternoon shade keeps plants cooler and less stressed.

You can also interplant tomatoes with taller crops like corn and trellis vining plants on the west side to provide shade. Just be sure not to completely block the sun—tomatoes still need at least 6 hours of full sun per day.

Mulching Plants

Apply 2-3 inches of organic mulch like straw, leaves, or wood chips around each tomato plant. The mulch acts as insulation to keep soil cooler and evenly moist. It also prevents weed growth.

Replenish the mulch as needed throughout the season. Mulching is especially important for reducing soil temperature and water loss during hot, dry spells.

Providing Consistent Water

Tomatoes need at least 1-2 inches of water per week from rain and/or irrigation. During hot weather, water demands increase. Soil can dry out quickly, causing drought stress.

Check soil moisture daily and water when the top few inches become dry. Prioritize giving plants a deep soaking in the morning, so the foliage has time to dry out before night.

Automatic drip irrigation or soaker hoses make watering simple. They also deliver water right to the roots where it’s needed most.

Adequate, consistent moisture prevents cracking and blossom-end rot in fruits. Proper watering is critical for helping tomatoes endure heat waves.

Picking Tomatoes Early

When an extended hot spell is forecast, harvest any mature or ripening tomatoes. Allow them to finish ripening indoors. Counter-top tomatoes will likely taste better than heat-stressed fruits left on wilting vines.

High temperatures often cause tomato flavor to decline. Picking fruits early when possible gives you the best chance of fully ripe, delicious tomatoes.

Location, Location, Location

Where you situate your tomato garden factors into how much heat stress plants experience. Avoid hot south-facing walls and asphalt that radiate heat. Instead, locate tomatoes where they’ll have access to cooling breezes.

North-facing sites and areas shaded by trees or buildings in the afternoon help buffer tomatoes from intense sunshine and heat. If possible, position your garden near a body of water which moderates temperatures.

The hardiness zone map provides clues about potentially hot microclimates. Know your zone and span of seasons to select suitable tomato varieties and weather-wise planting times.

Start Plants Indoors

Getting a head start on the season by growing transplants indoors allows you to time tomato planting based on weather conditions. Hardening off and transplanting partially mature plants once soil has warmed minimizes exposure to extreme heat.

Wait until after the average last frost date and nights stay above 55°F before setting out tomatoes. Follow the mantra “knee high by the Fourth of July” as a guide for transplant timing.

Monitor for Problems

Heat and drought stressed tomatoes are magnets for pests and diseases. Be vigilant about checking for early signs of tomato troubles. Remove damaged leaves immediately to prevent infections from spreading.

Control tomato hornworms, flea beetles, mites, and other pests before they get out of hand. Keep the garden tidy by promptly removing any dead or dying foliage. Good sanitation is key to avoiding issues.

Know When to Call It Quits

Some years, the heat is just too much for tomatoes to take. If your plants are repeatedly wilting no matter how much you water, it may be time to pull them out.

There’s no shame in throwing in the trowel if weeks of high temperatures have fried your tomato crop. Give it another go in the fall when conditions are cooler, or plan to start tomatoes earlier next spring.

Enjoy the Bounty of Heat-Loving Tomatoes

Don’t let high temperatures deter you from growing tomatoes. With heat-tolerant varieties, adequate water, and a little shade, you can harvest bushels of summer’s favorite fruit.

Pay attention to tomato preferences, but don’t stress over achieving perfect conditions. Focus on ways to keep plants as cool and comfortable as possible. Stay alert to ripening tomatoes, and pick frequently to stay ahead of the heat.

With a little trial and error, you can discover the best methods for growing tomatoes successfully despite Mother Nature’s attempts to turn up the heat. Stay positive and enjoy the fruits of your efforts!