Tomatoes are one of the most widely grown vegetables in home gardens. But extreme temperatures can make growing tomatoes challenging. So what’s the ideal temperature range for tomatoes and how hot is too hot for them? This in-depth guide has all the answers on tomato heat tolerance.

The Optimal Temperature Range for Tomato Plants

Tomatoes thrive in warm conditions but can suffer once temperatures get too high, The ideal temperature range is

• Daytime: 70-85°F
• Nighttime: 60-70°F

Temperatures consistently above 90°F during the day and 70°F at night usually cause issues like poor flowering, blossom drop, and reduced fruit set.

Tomato pollen becomes nonviable at 85-90°F and higher This prevents flowers from being pollinated and setting fruit, Prolonged exposure to temperatures over 100°F can even be fatal to tomatoes

While tomatoes can withstand short hot spells, extended extreme heat takes a major toll on productivity. For best results, keep tomatoes within their optimal range as much as possible.

Choosing Heat-Tolerant Tomato Varieties

Certain tomato varieties are bred to be more heat-hardy and set fruit in high temperatures. Look for heat-loving cultivars like:

• Solar Fire
• Phoenix
• Heatmaster
• Summer Set

Compact determinate types tend to be more heat-tolerant than sprawling indeterminates. Cherry tomatoes like Sun Gold, Husky Cherry Red, and Sweet 100 also hold up well.

For slicing tomatoes, Celebrity, Better Boy, and some disease-resistant hybrids are good options for warm climates. Ask local nurseries for variety recommendations suited to your area.

Providing Afternoon Shade

Too much sun can overheat plants. Giving tomatoes 30-50% shade, especially from early afternoon to late evening, helps reduce heat stress.

Use shade cloth, awnings, or shelters to block sunlight during the hottest parts of the day. Still allow maximum morning sun exposure. Afternoon shade keeps plants cooler and less stressed.

Mulching

Apply 2-3 inches of organic mulch like straw, leaves, or wood chips around each plant. The mulch insulates soil, keeping it cooler and evenly moist. It also prevents weed growth.

Replenish mulch as needed through the season. Mulching is critical for reducing soil temperature and moisture loss during hot, dry conditions.

Watering Consistently

Tomatoes need 1-2 inches of water per week. During hot weather, demands increase as soil dries out rapidly.

Check soil moisture daily and water when the top few inches become dry. Prioritize deep watering early in the day so foliage can dry before night. Drip irrigation delivers water right to the roots.

Adequate, consistent moisture prevents issues like blossom-end rot. Proper watering helps 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 where they’ll likely taste better than heat-stressed fruits on vines.

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

Location Matters

Where you situate your tomato garden affects heat stress. Avoid hot south-facing walls and asphalt that radiate heat. Instead, choose sites with afternoon shade and cooling breezes.

North-facing locations shaded by buildings or trees help buffer from intense sun. Position gardens near bodies of water to moderate temperatures.

Start Plants Indoors

Growing transplants indoors allows you to time planting based on weather. Hardening off and transplanting partially mature plants once soil warms minimizes heat exposure.

In most areas, wait until after the last spring frost with consistent 55°F+ nights before setting out tomatoes. This is often around early July.

Monitor for Issues

Heat and drought stressed tomatoes readily develop pest and disease problems. Monitor closely and remove damaged leaves immediately to stop infections spreading.

Control pests like hornworms and mites before they proliferate. Keep dead or dying foliage cleaned up. Good sanitation avoids issues.

Know When to Quit

Some years, the heat is just too extreme for tomatoes. If plants keep wilting despite adequate watering, it may be time to pull them out.

There’s no shame in giving up if weeks of record highs have devastated your crop. Try again in fall when it’s cooler or start tomatoes earlier next year.

Enjoying a Bountiful Summer Harvest

With heat-tolerant varieties, shade, consistent moisture, and attentive care, you can harvest bushels of tomatoes despite Mother Nature’s heat waves.

Focus on keeping plants as comfortable as possible. Stay alert for ripening tomatoes and pick frequently to stay ahead of the heat. A little trial and error will help you discover the best methods for success in your climate.

Key Takeaways on Tomato Heat Tolerance

• The optimal temperature range for tomatoes is 70-85°F during the day and 60-70°F at night.

• Once temperatures consistently exceed 90°F in the daytime or 70°F overnight, tomato plants often struggle.

• Choose heat-tolerant varieties, provide afternoon shade, mulch, and water deeply and consistently.

• Monitor plants closely and pick tomatoes early to get the best flavor before extreme heat damages quality.

• With proper care, tomatoes can still thrive and produce abundant harvests despite hot weather.

Growing tomatoes in hot conditions takes some extra effort but is very doable. Follow these tips to help your tomatoes successfully tolerate the heat!

Tomatoes don’t handle 100-degree weather well. While they enjoy warm weather, prolonged exposure to temperatures above 85°F (29°C), especially with warm nights, can lead to blossom drop and reduced fruit production.

To protect tomato plants from extreme heat, focus on providing shade, maintaining soil moisture, and choosing heat-tolerant varieties. Shade cloth or row covers can shield plants during the hottest hours, while mulch helps retain moisture.