Hot Climate Gardening Tips
We’ve just experienced a couple of weeks of very warm temperatures, and meteorologists are predicting that we’ll continue to see above-average temperatures this summer, which will continue for some years.
Cool-Weather Crops
These plants don’t tolerate hot weather:
Broccoli
Kohlrabi
Chinese cabbage
Brussels sprouts
Carrots
Radishes
Kale
Swiss chard
Cauliflower
Lettuce and other salad greens
Spinach
Peas
In the vegetable garden, it’s the cool weather crops — lettuce, spinach, arugula, broccoli, kale, cauliflower, peas, cilantro — that suffer in hot weather. Even with an abundant and consistent supply of water, when temperatures rise over 80 degrees, these plants tend to stop growing, go to seed, or just give up the ghost.
Summer Gardening Tips
Tip #1: Water Deeply
One of the biggest threats to your plants during the hottest months is a lack of water. Plants lose H₂O through their leaves, and soil surfaces dry out quickly, leaving shallow roots thirsty.
You can protect your plants from water loss by watering long and slow, a good practice to start even before your temperatures near the triple digits. By doing so, you encourage your plants to develop deeper roots, which will help them find nutrients and water during long, hot afternoons.
Watering only a little bit every day or only wetting the top few inches of soil, in contrast, tells your plants to keep their roots short, to better find water near the surface of the soil.
Additionally, soil that’s damp throughout maintains a more consistent temperature and is less likely to dry out, which would put stress on your plants. Your goal should be soil that’s damp to the touch at all times (never soggy and never fully dried out).
Tip #2: Water in the Morning
The morning is the best time for watering because that’s when your plants and soil are ready to take in water. As soon as the sun’s up, plants start using water, and if the soil isn’t fully wet, they’ll adapt to partially dried root zones by producing abscisic acid (ABA), which stimulates the leaves to close stomata slightly, reducing water loss. By the time you start watering in the morning, there is both a soil moisture deficit to hold the water and an immediate demand for it from the plants, reducing the water that’s lost to deep drainage.
Similarly, by nightfall, when photosynthesis stops and stomata close, the root zone is left with a moisture deficit again to stimulate the ABA effect the next morning. By not watering at night, you also avoid encouraging slugs, snails, and mildew.
Tip #3: Use Shade Cloths
Your plants can’t move to stay under the cover of shade like you can. If you want to reduce the intensity of bright sunlight and heat beating down on your plants, you’ll have to bring a little shade to them.
Shade cloths are effective tools to protect your plants from too-bright sun and keep the surrounding soil cooler, helping it to better retain moisture. They allow enough airflow and sunlight through to keep your plants happy without scalding them.
Shade cloths are relatively inexpensive, reusable, and readily available at garden centers or online. To avoid squishing your greens, tent them over wire arches or garden hoops.
I find it best to pull warm-season plants like tomatoes from the garden during the hot season, but shade cloths can buy you a bit more time with your fruiting plants before it’s time to say goodbye.
Tip #4: Grow the Right Plants
Some plants are just not meant to live long once the temperature rises above 70 degrees. By growing plants that are more tolerant of a warm climate, you can spare yourself the frustration of wondering why your spinach is bolting or why your tomato plants are no longer producing.
Plants like tomatoes, some peppers, squash, and beans are considered quintessential summer staples, but they actually grow best in hotter climates during the spring and fall. They’ll slow their production and become stressed when temperatures spike over 90 degrees (and stressed plants invite pests to your garden).
You don’t have to give up growing your favorite things entirely during summer, just pick varieties that are locally sourced or that are known to perform well in your area. If you love salad greens, go for arugula, New Zealand spinach, and mizuna. If you want to look out your kitchen window and see fruits growing in abundance, grow okra or eggplants.
Growing plants that are better adapted to your climate instantly boosts your chances of gardening success.
If you live in or near Central Texas, check out my Monthly Planting Guide to learn what you can grow over the summer. Otherwise, I suggest finding a garden coach near you and following them on social media to see what they’re planting and when. Follow their lead to grow the right plants for your area.
Tip #5: Go Easy on Younger Plants
Extreme summer temps are hardest on tender young plants with more shallow root systems. If you move a transplant or seedling out to your garden between June and August, make sure to harden it off first. Let it get used to the conditions in its new home in the morning, and then keep it under shade for the hottest hours of the day. Do this for a week or two before you finally plant it.
Look for a spot in your garden where it can receive some shade from your taller, more mature plants in the hottest afternoon hours (or use shade cloth).
Tip #6: Big Plants Keep Your Garden Cool
There are so many things to love about trees, shrubs, and hedges. When it comes to managing water, they cool the garden and are the least likely to need watering themselves.
When it’s hot, big plants pump out moisture from their broad leaves through evaporation, which absorbs heat in the atmosphere. This cools the garden, along with the shade they provide. And in a dry spell, with their deep roots, they can access moisture without being watered.