Hot weather can stress even the most heat tolerant plants. Your garden will need special care to survive extended dry periods and heat waves. Fortunately, these tips from Penn State Extension can help you out.
During a drought or long period without much rainfall, watering your vegetable garden becomes extremely important. Not only do your plants need the water, but wet soil can protect your plants from the heat. After it’s been watered, the soil will stay cooler. Watering your garden before the soil gets dried out also ensures good absorption. Soil that’s been dried out does not absorb well, allowing water to run off rather than soak into the ground.
While watering your plants is important during periods of hot weather, good drainage is key. If you end up with compact water-logged soil, it can be especially damaging to plant roots because they need more oxygen during periods of hot weather.
Avoid black plastic mulch at all costs during hot weather. It literally cooks the soil. Instead use unprinted cardboard, straw or organic matter to mulch your garden. These types of mulch will help it retain moisture and lower the soil temperature.
Healthy plants will survive hot weather more easily than weak plants. Plants that have been fertilized properly, receiving the right amount of nutrients, will tolerate hot weather better and recover from wilt injury faster. Generally, fertilizer should be applied before you plant your vegetable garden or early on in the growing season. However, if you need to give your garden a nutrient boost later than that, make sure you don’t pour too much liquid fertilizer on or near the leaves. It can burn them.
Good air circulation is always important, but especially so during periods of hot humid weather, as disease can spread more easily in a garden that is too densely planted. If your garden is looking more like a thicket by midsummer, it’s better to cut out some stems and foliage to increase air circulation.
Pro tip: Disinfect your pruning tool between plants with a 1:3 bleach and water mixture to prevent spreading disease from one plant to the next.
Bolting or the premature growth of a flower stalk is triggered by changes in day length and commonly associated with hot weather. It can occur in lettuce, leafy greens, beets, cabbage and celery, and turns them bitter. To avoid bolting, consider choosing slow-bolt or bolt-resistant plant varieties.
If you’re considering seedlings for fall crops such as broccoli, Brussels sprouts, cabbage, and cauliflower, you should know they are more susceptible to heat than any other plant in your garden. If you haven’t planted your fall seedlings yet, consider planting them along a shade barrier or in the shade of other taller vegetables to protect them from direct sun. If you’ve already planted them, consider using a shade cloth.
A shade cloth is a good investment if you grow leafy greens throughout the summer. It’s basically a black netting that you can buy in various densities to block out different percentages of light. Most vegetables prefer a 30-50 percent shade cloth. Once it’s installed, the shade cloth should not come in contact with the plants, otherwise, the heat from the cloth can burn the plants, and the movement of the cloth in the wind can damage the plants. The shade cloth should be securely attached to poles.
Pro tip: You might also consider installing a windbreak to protect your seedlings from the hot summer wind, which can dry them out.
Harvest your produce during the cooler hours of the day. Strong midday sun can wilt or dry out your fruits and vegetables. After they are picked, move your fruits and vegetables to a cooler location and wash them immediately to remove field heat. You might also consider harvesting your produce and placing it directly into an ice chest for a similar effect.