Tomatoes are the divas of the vegetable patch — luscious, celebrated and notoriously hard to please. If it’s too chilly, they’ll sulk. If it’s too hot, they’ll throw a tantrum, scattering their blossoms and refusing to perform.
Gardeners everywhere know that planting tomatoes prematurely in spring is a mistake. They will just sit there until the soil warms up. New transplants put in later will soon catch up and even overtake them.
The opposite problem — searing temperatures later on — is more complicated, and though hot weather is weeks away, now is the time to prepare for the plants’ summer needs.
The tomato is a warm-weather creature. Although leaf crops such as lettuce, spinach and kale are most productive when it’s cool, tomatoes need plenty of warmth and sun to ripen those juicy red orbs.
But when temperatures rise into the 90s and above and stay there for a stretch of time, several bad things happen. The plants become stressed, desperately trying to pump water and nutrients through their systems as moisture evaporates from their leaves. Days of hot sun can cause sunscald, a disorder that produces whitish patches on the fruits and invites disease. The pollen in the plants’ small yellow flowers is ruined as well. Unable to make fruit, they fall to the ground.
Siting the garden in a spot that gets dappled afternoon shade from nearby trees will help a lot. Even a row of tall sunflowers might do the trick. Or you might erect a simple frame from wooden poles or metal pipe, to support sheets of black shade cloth with a 50 percent light transmission. The stakes, cages, fences or trellis you use to support the vines could have shade cloth draped over them until the heat wave passes. Watering deeply and evenly will reduce heat stress.