When you think of hot weather you might imagine sipping a cool drink, swimming in the pool, or enjoying the indoors with a working A/C. But if you have a garden, that hot summer weather could mean your plants are suffering. Depending on where you live, it may be vital for you to learn how to protect your garden in hot weather.
The closer you live to the equator, the more heat you’ll have to deal with. You could have a few weeks of warm weather, or that could be the norm all year round. There are different fruits and vegetables that grow better in different temperatures and climates. For example, stone fruits do better where winters are cold, and tropical plants do better where the winters are very mild. There are benefits to warm weather, but sometimes our gardens can use a little help during those hot months. Below we’ll discuss the effect hot weather can have on your vegetable garden, your heat-tolerance zone, and what you can do to protect your garden in hot weather.
The Effect of Hot Weather on Your Garden
When temperatures rise above 86°F (30°C), many plants start to suffer. However, with adequate care, the effects of heat stress on plants can be minimized. Plants can show heat stress by wilting, which is a sure sign that water loss has taken place. If this is ignored the condition can worsen and the plants will eventually dry up. In some cases, leaves can turn yellow or get scorched by the sun.
Heat stress can also show up through leaf drop. Plants actually shed some of their foliage in an attempt to conserve water. Plants can also have difficulty producing fruit. Fruiting plants like peppers, tomatoes, eggplant, squash, melons, cucumbers, pumpkins, and beans will usually drop their blossoms in high temps, while cool-season crops, like broccoli, will bolt. Blossom end rot is also common during hot weather and more prevalent in tomatoes, peppers, and squash.
Warm-season crops such as eggplant, peppers, tomatoes, corn, melons, and squash need at least a month of 80 to 90°F weather to develop a flavorful crop. On hot days they conserve energy and moisture by slowing down. While resting, their foliage may appear to be wilting from lack of water, but as evening approaches they’ll perk up again.
Cool-season crops on the other hand don’t tolerate heat. These include broccoli, brussels sprouts, carrots, cauliflower, Chinese cabbage, kale, kohlrabi, lettuce and other salad greens, peas, radishes, spinach, and swiss chard. Even with precautions when temperatures rise over 80°F they tend to bolt or stop growing.
Know Your Heat-Tolerance Zone
A heat zone map was developed by the American Horticultural Society (AHS), based on the National Weather Service daily high temperatures recorded between 1974 and 1995. The AHS Heat Zone Map includes 12 zones, each indicating the average yearly number of days with temperatures over 86°F (30°C). This threshold represents the point when the plants start suffering from the heat. These Heat zones range from less than one heat day (Zone 1) to more than 210 heat days (Zone 12). This is similar to hardiness zones for cold weather.
This map can be used as a guide. But don’t let it limit you. You can experiment with creating a microclimate for your garden to extend growing seasons and beat the heat.
How To Protect Your Garden in Hot Weather
Once you know how many days you have to deal with temperatures above 86°F you can figure out how you’d like to deal with that time. One option is to pause and wait until temperatures start to cool. Here in Florida, some people do that. But if you do find yourself living in a warmer zone, there are actions you can take to prolong your growing seasons. You can water your garden appropriately, add mulch, weed, and provide shade for you garden can help your crops during hot weather.
Watering Your Garden in Hot Weather
Watering your garden during hot weather is a great way to keep your plants well hydrated to fight off the stress of high temperatures. I typically water once a day here in Florida when it’s warm. It’s best to water either early in the morning or in the evening to avoid the midday sun. It’s best to use a drip irrigation system, but if you don’t have one just be mindful of not getting your leaves wet (which can leave them scorched if they don’t dry before midday sun). Vegetables need a reliable, steady water supply to stay productive. Make sure you water regularly and deeply.
Container plants may need additional attention. You may find yourself needing to water potted plants twice a day during high temperatures. Soak them until you see water coming out of the bottom drainage holes. You may also want to move your pots to locations that are shadier during the heat of the day
Mulching Your Garden to Keep Cool
Mulching your garden during hot weather can also keep your plants cool. Having 2-3 inches of wood chips or straw can provide a ground covering that protects your soil. It allows for moisture to be retained, prevents weeds from growing quickly, and lowers temperatures for your plant roots. When mulching just keep in mind that you may need to add extra nitrogen to your soil.
Weeding Your Garden to Prevent Competition
Weeding your garden in hot weather prevents competition between weeds and your plants from soaking up the water you’re providing. By making sure your garden is cleaned up and weeded you can ensure that the water you add isn’t going towards growing something you won’t be eating.
Shading Your Garden in Hot Weather
Shading your garden in hot weather is a great way to keep your garden cool. You can do this by planting your garden or keeping your pots in a location that is protected by the midday sun. Creating shade over your plants can also help your garden stay cool.
You can create shade with shade cloths, which are also known as garden fabric and row covers. Shade cloths are made out of a thin gauze material that still lets light through. This can protect tender foliage from being scorched by sunlight and reduce moisture loss. Shade cloths can also keep soil and air temperatures as much as 10 degrees cooler.
I typically use shade cloths in the garden between April and October when the days are longer and hotter.
When you use all of these tactics you should be able to lessen the stress of heat on your garden and enjoy your harvests for a longer period of time.
How do you deal with the heat? Comment below!