Heat Tolerant Tomato Varieties For Your Summer Garden

Tomatoes are heat-loving, sun-loving vegetables, but when the temperatures soar too high, the plants will stop setting fruit and eventually die off. Does that mean that gardeners in southern and southwestern regions can’t enjoy those juicy, sweet harvests? Thankfully, that’s not the case!

All that needs to be done is to choose the best tomatoes for the hot climate and give them suitable care to ensure they thrive and give plenty of ripe tomatoes at the end of the growing season.

Heat-tolerant tomato varieties are specially designed to give a hardy crop that won’t mind the summer heat. They will blossom and fruit with full vigor despite the high temperatures. What varieties should you go for and how best to keep them thriving. Read on and learn all about tomato gardening in hot climates.  

How Hot Is Too Hot For Tomatoes?

Most tomato varieties are warm-season vegetables and are best planted when all the dangers of frost have passed. The optimal temperatures for blooming and fruit set are between 65°F to 80°F. 

If the daytime temperatures exceed 95°F, the plants’ ability to set fruit and develop it to maturity will be adversely affected.

Prolonged exposure to high temperatures causes them to go into heat stress. As a defensive response, the plant increases transpiration and focuses its energies on surviving, rather than blossoming and fruiting. Not only does it slow down the development of the plant, but it also makes it susceptible to diseases and infestations.

Are Beefsteak Tomatoes Heat Tolerant?

Those big, meaty, juicy tomatoes that fall in the category of beefsteak tomatoes grow best when the soil temperatures are between 60 to 90°F. While Heirloom Beefsteak might not be too hardy to high temperatures, special hybrids have been developed over the ages to tolerate high temperatures better.

If you want to go for the same great flavor and yield as the original beefsteak, but with better heat tolerance, you might want to go for beefsteak hybrids. Big Beef, Black Krim and Cherokee Purple are all excellent beefsteak tomatoes for growing in hot climates.

What Tomatoes Grow Best In Hot Weather?

There are a bunch of heat tolerant tomato varieties that have been developed for performing better in hot, arid regions. These are known as “heat-set” or “hot-set” tomatoes and will often set fruit earlier than the other varieties to be harvested before the temperatures reach their peak. Here are some of the most common heat-tolerant varieties for your garden:

Heat-Tolerant Hybrids

Big Beef

It’s a juicy, mouth-watering beefsteak hybrid that will bear large fruits in 73 days. It’s disease-resistant, heat-tolerant, and also performs well in cool, wet weather.

Fourth of July

Fourth of July or ‘Independence day Tomato’ is an early-season tomato that ripens in 49 days, producing small, plentiful tomatoes.

Bush Early Girl

It’s an excellent heat-tolerant tomato to plant in containers and gives a high yield with 7-ounce tomatoes.

HeatWave II

It’s a determinate tomato plant that matures in just about 55 days, producing great-tasting 7-oz tomatoes at temperatures as high as 95°F.

Sunmaster

This is another determinate tomato that matures in 72 days and produces juicy, globe-shaped tomatoes even when temperatures exceed 90°F.

Sun Leaper 

Sun Leaper is a determinate hybrid that matures in 82 days and produces large, round tomatoes. It is very forgiving of harsh climates.

BHN216, Sun Pride, Talladega, Solar Fire, Heat Master, Florida 91, Summer Set, Florasette, Sunchaser, Rapsodie, and Equinox are also excellent heat-tolerant hybrid tomatoes.

Heat-Tolerant Heirlooms 

If you’d rather go for the heirlooms, there are plenty of varieties that are well-suited to warmer climates. Here’s a list:

Black Krim

An indeterminate beefsteak heirloom that produces 10-ounce maroon tomatoes, reaching maturity in about 70 to 90 days after transplant.

Arkansas Traveller

It’s an indeterminate heirloom that matures in 90 days, tolerant to heat, humidity, and drought, and produces juicy, medium-sized tomatoes.

Green Zebra

Green zebra is a determinate heirloom that produces green-yellow striped tomatoes, reaching maturity in 78 days. 

Super Sioux

This indeterminate tomato variety matures in 70 days, producing clusters of red, 4-ounce tomatoes and is excellent for hot, dry climates. 

Other than these, Eva Purple Ball, Tropic, Neptune, Illinois Beauty, Sioux, Costoluto Genovese, Homestead 24, Quarter Century, and Hazelfield Farm are also great heirlooms to grow in hot climates. 

How Do You Protect Tomatoes From Extreme Heat?

Besides choosing heat-tolerant tomatoes to plant, there are some tips that can help you maintain a healthy tomato crop through the hot weather.

• Don’t keep them thirsty

Pretty much like us humans, plants tend to get thirsty more often as the temperatures rise. Keep them well watered. Water them regularly, keeping the soil consistently moist but not waterlogged.

• Mulch

Mulching the soil around the plants with organic material like straw, leaves, or grass clippings helps keep the soil temperatures down. It also reduces evaporation from the soil, which is substantially higher in the heat.

• Planting Time

Gardeners in the tropics of subtropics are better off planting their tomato crop in winters. If you live in a hot climate, you can also start the plants indoors well before the last frost and transplant them in the garden after the frost. They will reach maturity before the summer temperatures reach their peak. 

• Give Them Shade

Use a shade cloth over the plants to allow beneficial sunlight to reach the plants but block the excessive heat, especially during the hottest hours of the day. Make sure tha plants are protected from the afternoon sun.

Heat Stressed Tomato Plants

Though tomato plants prefer sunshine and warm temperatures, prolonged exposure to very high temperatures can cause heat stress and wilting in tomato plants. Let’s look at the symptoms of heat stress in tomato plants and some practical ways in which damage can be reduced. 

Symptoms of Heat Stress in Tomato Plants

If the plant has sufficient water in the soil, and you still notice reduced plant size, fewer number of leaves, shriveled, curling leaves, dry or dropped flowers suggest that the plant is suffering from heat stress.

Since pollen and stigma viability suffers as a result of increased heat, the fruit set is also poor. Additionally, anthesis, pollination, and fertilization will also be negatively affected due to heat stress, contributing to a reduced yield. 

Tomato varieties with greater heat tolerance may set some fruit, but the fruit size will be smaller and ripen early. The reason is that cell expansion is inhibited as a result of heat and the plant produces greater amounts of the hormone ethylene. Ethylene is a hormone that promotes fruit ripening. Increased amounts of this hormone cause the fruits to ripen faster than they can expand.  

Recovering Tomato Plants With Heat Stress

Recovery of heat stressed tomato plants is a slow process. Still, with some patience and persistence, you can reduce some of the damage and save the harvest from the plants. Here are some steps you can take:

1. Since stressed plants have fewer leaves, the chances of cracked fruits are higher. It’s important to install a shade cloth over the plants to protect the developing fruits from the intense sun until the plants put on some green growth.
2. Overhead sprinkling can help lower the plant and air temperatures to some extent at least. However, there’s a potential of exposing the plants to disease damage from this watering approach. Water plants more frequently than usual to keep the temperatures down. However, avoid flooding the soil.  
3. Heavy fruits on heat stressed tomato plants can weaken them further. Ripen fruits as they reach their full size and start to change color. Allow them to ripen off the vine to prevent the stressed plants from spending their energies on ripening of the fruits. 
4. Don’t apply fertilizers to stressed plants since it can elevate the damage. Delay the use of fertilizers until after the temperatures have cooled down and the plants start putting on new growth on the branches. 
5. Prune the dead leaves, but only once the high temperatures subside. Even the dry leaves can offer some protection to the developing fruits from the intense sun. Once the temperatures cool down, prune the plants only lightly, removing the foliage that’s completely dry and brittle. It will help the plant concentrate its energies into developing new growth instead of focusing on reviving the damages leaves.