So we’re approaching that time of year when your tomato plants have fruit, they look good, they are starting to ripen and – boom – 100 degrees hits and we all worry we’ll lose the crop before steady high temperatures take hold. What to do?
Invest in 50% shade cloth or a big roll of burlap. Both offer great protection. Never use more than 50% because too much shade basically stops any growth activity for the tomato plant. The differences between burlap and shade cloth are slight. Both offer about 50% shade, but shade cloth is plastic so it will last several seasons. Burlap will eventually rot out after a year or so, but has many uses. It’s a good frost cloth in the winter (remember this past January?) or use it to cover seedlings when they are young and vulnerable to birds.
The correct shading is important because you want to keep the plant and its roots cool. This accomplishes two things: It helps avoid blossom drop as temperatures rise and it keeps the plant’s pollen cool.
Tomatoes grow best in temperatures between 70 and 90 degrees Fahrenheit, but can tolerate temps lower than 55° F and higher than 100° F for short periods. However, extended periods lower or higher than these temperatures make a tomato plant drop its blossoms, so shading keeps a plant cooler than the stated temperature.
The pollen of most tomato plants becomes sterile at 90° F and tomato production often ceases during hot periods.
Shading tomato plants also gives the fruit time to ripen on the vine, which is the whole reason we grow them in the first place. We love the vine-ripened flavor. For red fruit types, wait until a deep red uniform color is achieved, and for the best flavor, pick the fruit just before use.
Gotta Have Your Tomatoes Now?
Some people will not want to bother with shade cloth or they may be heading out of town and want to salvage the tomatoes they can while they are still green. Our grower pal Gregory Ware dislikes this idea. He says, yes, the tomatoes will become red, but asserts they will never really ripen and they will be hard and lack taste – like most grocery store tomatoes.
Other folks recommend ripening tomatoes in a paper bag containing a banana or apple. And a Tucson source says to line a shallow container with newspaper and carefully place the tomatoes on top. It’s important not to let the tomatoes touch each other, and do not wrap the tomatoes with newspaper. Then store them in a cool, dark location, keeping an eye out for rot. If one fruit rots, get rid of it. When the tomatoes start turning colors, bring them up on your kitchen counter and you will soon enjoy fresh, ripe tomatoes.
Our best advice? Cover those plants in the next week with 50% shade all day and drape it down to the ground on all sides. Then as your tomatoes ripen, enjoy the fruits of your labor.