Caring for tomatoes during heat and drought can be a challenge, especially if they’re growing in a container.

When the temperatures reach into the 90s, you can expect to water them daily. In the case of my prize Fourth of July tomato planted in a 14-inch pot, I have to water twice a day.  My container is sitting in a shallow saucer that catches excess water that may have drained out too quickly and failed to fully moisten the soil. So, if the soil is dry, the water will still be drawn up into the pot.

When to water makes a difference in the quality of your tomatoes, no matter if they are planted in the ground or in a pot. Excessive wilting from lack of water stresses plants and affects the texture and taste of the fruit. Also, when the plants dry out, the uptake of calcium is interrupted, which causes blossom end rot, the ugly blackened patch on the bottom of the tomato that ruins its looks. So, it’s best to water them in the morning before the sun hits them. In high heat and drought, I water them again in the evening.  

If your tomatoes wilt in the heat of the day even though you have watered them well in the morning, the cause is not lack of water. In high heat, plants can’t take up water from their roots fast enough to make up for their loss through the leaves and they often wilt. However, if they have been well watered before the sun hits and weather heats up, the wilting will not be as severe and less damage is done.  

To help my prized tomato plant cope with the heat stress, I add my ‘rescue remedy’  to the water weekly. The recipe is as follows: 1 ounce of Neptune’s Harvest Seaweed plant food (liquid kelp) and 4 drops of Superthrive vitamin solution mixed in 1 gallon of water.

 In a 10-year study at Virginia Tech on bio stimulants, researchers found that seaweed extracts had a profound effect on the stress tolerance of plants.

Fertilizing is not recommended during drought and temperatures above 85 degrees but my tomato is planted in a combination of good quality potting soil and compost that will provide the nutrients the plant needs. 

While we are told tomatoes don’t set fruit in high temperatures, my Fourth of July tomato ( a smaller saladette variety)  that was covered with flowers when I received it several weeks ago is currently sporting mo50 fruits.   

Nancy Szerlag is a master gardener and Metro Detroit freelance writer. Her column appears Fridays in Homestyle. E-mail her at , Ask Nancy. You can also read her previous columns at

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