Do Tomatoes Need Protection From Excessive Heat? Find Out 4 Ways To Protect Tomatoes In A Heatwave & Keep Plants Healthy

Tomatoes are some of the most popular crops for the home garden, yet also some of the most challenging. Today’s hybrids make growing your own a little easier, but even so, bringing a healthy crop to fruition requires some babying. One of the more surprising issues when growing tomatoes is their reaction to overly hot temperatures.

So do tomatoes need protection from excessive heat? It sounds odd, because this fruit requires full sun and warm temperatures – but a heatwave and tomato plants do not mix well. As with most things, timing is everything. High temperatures during pollination can bring tomato production to a screeching halt. Tomatoes react to overly high temperatures by refusing to pollinate. Extreme heat can also cause plants to wilt at critical moments of fruit development.

To protect your precious tomato plants in heat, it’s important to maintain good growing temperatures – and intervene quickly if you think a heatwave or drought is going to be a problem. If you suspect your tomatoes will need protection from excessive heat, read on for the key ways to keep plants safe, healthy, and fruitful!

When and How to Protect Tomatoes From Heat

Tomatoes thrive in temperatures up to 75-80°F (24-27°C) – and even 90 F (32°C) for a short duration. However, if temperatures reach 90-95°F (32-35°C) for a sustained period, especially if it's also really humid, then the plants won’t pollinate.

Overly long periods of high heat can also cause even the most laid-back and easiest tomatoes to stress and if fruit is present, scald. As far as pollination goes, high temperatures affect the structure of tomato blooms which, in turn, prevents pollen from successfully pollinating the stigma. The flowers also tend to abort or drop prematurely when temperatures are high, before pollination can even occur.

Maintaining healthy plant practices will help get many tomato varieties through a brief heat wave, but what else can you do, especially if there’s no end to the unrelenting temperatures? There are a few insider secrets to growing tomatoes in very hot spells. Here are a few key steps you can take if you want to know how to protect tomatoes from heat waves.

1. Choose Heat Tolerant Varieties

In a heatwave tomato plants that have high high tolerance have a natural advantage. Heat tolerant types of tomatoes will often be determinate varieties that pollinate and ripen earlier in the season, thus missing the heat extremes of mid to late summer.

Good heat tolerant varieties to try include ‘Heatmaster’, ‘Dixie Red’, ‘Phoenix’, tasty purple ‘Black Cherry’ and ‘Big Beef’ tomatoes. One of the most heat-tolerant is ‘Early Girl’, available from the Gardening Know How Shop, which is also resistant to diseases like fusarium wilt and matures two months after transplant. Alternatively, try ‘Arkansas Traveler’ from Burpee, a heirloom variety which is also disease resistant.

Select an area of the garden that gets morning sun with filtered light in the afternoon. Remember, however, that your tomatoes still need 6-8 hours of full sun each day.

2. Cover Your Tomatoes

If you lack a site that provides partial shade in the afternoon, think about covering the plants during the heat of the day. You can use almost anything to create shade. Shade cloths are great, of course, and there are some great shade cloth options for tomatoes at Walmart and also greenhouse shade cloth options at Wayfair.

That said, I’ve used old sheets and even a shower curtain in a pinch. Be sure to tent the cover to allow for air flow using stakes or by draping the cover over a line. Only cover the plants as the sun approaches its zenith. Remove the cover when temperatures drop down below 90°F (32°C).

3. Water Early and Deeply

Along the same lines if you want to know how to keep tomatoes cool, the right hydration is critical. Water ground-based tomatoes early in the morning to prevent evaporation. Water tomatoes deeply at the plant base. Give the plant at least an inch (2.5cm) of water daily, but during a heatwave, water the plants 2-3 times per day.

To check and see if the plants need water, stick your finger into the soil 2-3 inches (5-8cm) down. If the soil is dry, water the plants. Don’t panic if the plants wilt. This is a survival mechanism. Once temperatures cool, the plant will perk right back up.

4. Harvest Early

If all else fails, try to harvest tomatoes early. If a heatwave is imminent and the plant is actively growing fruit, you can certainly increase your chances of better tomato yields by harvesting early. The Garden Guru Hori Hori Knife from the Gardening Know How Shop is great for making neat cuts to stalks to release your juicy fruits.

Remember, the tomato fruits don't have to ripen on the plant. As long as they've reached the mature green stage, you can harvest tomatoes and then ripen them inside your home, perhaps on the kitchen counter or in a paper bag or cardboard box, stored in a cool dry area.

Help Tomato Plants Recover After a Heatwave

As well as caring for plants during a heat wave, there is something else to bear in mind. If you’ve already experience a bout of hot weather and you’re afraid your toms have suffered on the back of a heatwave, there are still a few things you can try to mitigate the damage, help plants recover, and salvage your crops:

• Keep watering deeply in the morning. Avoid watering during the day. You should still avoid fertilizing tomato plants for a while until they have rebounded. Otherwise, you risk stressing them further.
• Even if the heatwave has broken, the plant has been through stress, and it’s likely that it’s still pretty hot outside. So you may want to continue to provide shade for the plants during the midday heat.
• Remove any yellow leaves or dead foliage, which can open the stressed tomato up to disease and can weaken them overall, resulting in other issues such as pests.
• If you didn’t already do so, consider harvesting early. Especially if the plants don’t seem to be bouncing back from the hot temperatures. Ripen the fruit inside in a bag or box in a cool, dark area.

Frequently Asked Questions

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