How’s your garden doing this year? Unpredictable weather patterns have been the norm lately, and the challenge for the survival gardener is being adaptable with backup strategies that can keep the plants alive and productive despite the circumstances. High temperatures, heatwaves, and droughts are becoming more frequent and more intense, and last week was brutal in many parts of the United States. We’ve already talked about creating drought-resistant vegetable gardens and choosing what complementary flowers and herbs will survive low-water situations. What else can a survival gardener do to safeguard against heat waves?
Plant Physiology and Heat
Understanding how heat affects plants will help you plan. High temperatures can increase water evaporation from soil and plants, causing the plant to wilt and the soil to dry out. This can even happen in high humidity if plants aren’t adapted to high heat. Some vegetable plants can become heat-stressed and drop their flowers if temperatures exceed 90°F, so even though the plants might survive, they won’t produce. Heat can also stress plants, making them more susceptible to pests and diseases.
Choosing Resilient Varieties
Your first line of defense against heat starts when you choose your seeds. Some vegetable varieties are bred to tolerate heat and even thrive in high temperatures. Heat-loving fruits and veggies like tomatoes, peppers, eggplants, okra, watermelon, cucumbers, summer squash, and cowpeas are excellent choices. By selecting heat-tolerant and native plants adapted to your local climate, you can significantly increase your chances of a successful harvest. Whether your area is prone to hot summers or typically mild, it’s a great idea to incorporate some versatility into your garden to safeguard against unpredictable weather patterns.
No matter what plants you’ve chosen, water management is always critical to helping your plants survive extreme heat. Even heat-adapted plants need to be given appropriate amounts of water. You want to keep your soil moist without causing waterlogging, which can lead to root diseases. Deep watering encourages roots to grow deeper, where the soil remains cooler and more moist.
Timing is also critical. The most efficient time to water is in the early morning, which helps plants cope with the day's heat and minimizes water loss due to evaporation. Water at the soil level and avoid getting the leaves wet. A drip irrigation system can deliver water directly to the plant roots and significantly reduce water wastage.
Consider Your Containers
Since containers hold less moisture than the ground does, when the temperatures approach 100°F and higher, you may have to water your potted plants twice a day. If your containers are terracotta, metal, or dark black plastic, you may want to consider switching containers out entirely or finding some other way to combat the heat. Terracotta allows for very quick evaporation and will wick the moisture away from your plants’ roots in no time, and black or metal containers will absorb the heat.
Don’t neglect mulch! Open soil can easily erode, become crusted or compacted, or simply have poor drainage, all of which stress your plants and deprive their roots of moisture. A 2-3 inch layer of organic mulch, such as straw, wood chips, or compost, can significantly reduce water evaporation and keep the soil temperature stable during rising temperatures. A good layer of mulch will also suppress the growth of opportunistic weeds that will rob your plants of nutrients and water. As the mulch breaks down, it will continue to add organic matter to the soil.
Shelter from the Sun
Just like us, plants can also benefit from a break from the sun. Shade cloth can reduce the intensity of sunlight and protect plants during the hottest part of the day. Don’t place shade cloth too close to your plants, as the heat can radiate onto them. You can create temporary shade structures using shade cloth, stakes, or even repurpose old sheets or curtains in a pinch. If you're growing in pots or containers, you can move them around strategically as needed. Plants that get highly stressed in hot weather, like many green leafy vegetables, may need to come indoors.
Nurturing the Soil
Good soil is the foundation of any successful garden. Healthy soil promotes healthy plants that are better equipped to withstand heat and other stressors. Adding organic matter to soil can improve its structure, nutrient content, and moisture-holding capacity. Composting is an excellent way to recycle kitchen scraps and yard waste into nutrient-rich soil amendments. Plus, it’s easy to get started composting and hot weather is the perfect environment for breaking down your components.
Respond to Distress Signals
Spend time with your plants so you notice symptoms of heat stress which include wilting, leaf scorch, blossom drop, and reduced fruit set. Regular garden walks can help you identify the signs early and take corrective action, such as providing shade, increasing watering, or adjusting your mulch. Don’t give up easily; many plants will rebound once the temperature becomes more moderate. You may get a second harvest if you’re persistent.
Provide Water for Animals
You may have noticed that we love our friendly, hardworking pollinator neighbors. Our insect friends struggle in the heat just as much as the plants do. Clean water can help them to survive the summer heat. Make sure there’s a safe place to stand so they won’t fall in and drown, and replace the water regularly so mosquitos can’t breed. Providing a birdbath or other water source can also help save your garden from thirsty squirrels or chipmunks who will nibble up your juiciest fruits and vegetables just for their water content.
Planting in Succession
Don’t leave your soil empty or give up on your garden, even when the going gets tough. Succession planting crops in the same space as soon as the previous crop is harvested is a great way to adapt your garden to hot weather. If your plants are struggling, replace heat-sensitive crops with more heat-tolerant ones as the season progresses so that you can continue to enjoy a harvest through the growing season.
Use Cover Crops
If you have a crop failure and you don’t want to plant more vegetables, you can still use cover crops to improve your soil and protect it from the damaging effects of heat. Buckwheat is one of the best choices for a summer cover crop. It grows quickly and will improve the soil in time to plant a fall garden. Cowpeas and bush beans can also be used as summer cover crops because they will grow quickly in the heat and fix nitrogen to improve your soil.
Embracing a New Gardening Ethic
Gardening in extreme heat - and survival gardening in general - requires more than new techniques. In fact, many of these techniques are not that difficult or unusual, but they may simply be different. Changing the way you look at gardening is vital to handling the unexpected, so try to be more adaptable, more resilient, and more observant. As we become more aware of our local ecosystems and climate, and more attuned to the subtle signs our plants give us, we can make changes that improve not only our own lives but the local environment and the lives of others around us.
Extreme heat can be a formidable challenge for vegetable gardeners. But with the right strategies, and a bit of patience and resilience, it's a challenge that we can overcome. By understanding how heat affects our plants, choosing the right plant varieties, managing our water wisely, and nurturing our soil, we can turn our gardens into resilient food production systems that not only survive but thrive in the heat. Happy gardening!