Although the heat of summer is when many vegetables thrive, too much heat won’t do your plants any favors. Even heat-loving plants like tomatoes can easily overheat on especially hot days. So with heat waves becoming more and more frequent, it’s important to have plans in place to keep your crops from overheating.
Here are some tips for keeping your crops cool, as well as some longer-term ideas for creating microclimates on your farm.
Shade cloth is exactly what it sounds like: a cloth-like material that blocks a certain percentage of sunlight. Depending on the tightness of the weave, shade cloth can filter out up to 95 percent of incoming light.
In some cases, growers install shade cloth semi-permanently to grow under for an entire season. In other cases, growers may keep shade cloth on hand to cover a hoophouse or low tunnel on an especially hot day.
The website for Johnny’s Selected Seeds provides a good overview of how to use various percentages of shade cloth. No matter how you use it, shade cloth is an effective tool for taking the edge off the summer heat.
Many people have strong (sometimes differing) opinions about irrigating vegetables in the summer heat.
I’ll tell you what works for me. If I know a real scorcher is coming, I’ll check the soil early in the morning and run drip-tape lines as needed. Give the plants a good watering but don’t go crazy. Just because it’s hot doesn’t mean that it’s impossible to overwater.
Most importantly, watering early in the day helps to minimize losses from evaporation. It also sets me up to monitor moisture levels for the rest of the day and run the drip tape again here and there as needed.
If you’re noticing that a section of your garden is baking, setting up a temporary fence can provide a short-term solution. Make sure to orient the fence so that it’s blocking sunlight for whatever portion of the day you want it to.
I’ve used snow fence and burlap before, but anything that provides shade will work. Just make sure that your fence is strong enough not to blow away in the wind, but not so permanent that you can’t easily take it down.
Although temporary fixes can be helpful, there are also longer-term strategies you can use to help keep your growing area from overheating. For starters, you can use more mulch. Although the mulch won’t cool your crops’ foliage, it will help to keep your soil from overheating and improve water retention.
Plus, mulching helps to improve your soil health in other ways, including adding organic matter and preventing erosion.
Permanent windbreaks interspersed throughout your growing area can also create cool microclimates. Beyond providing wind protection and shade, windbreaks can also create habitat for beneficial wildlife and pollinators. Singing Frogs Farm in Sebastopol, CA is notorious for incorporating windbreaks into their fields.
With more and more heat waves coming, it will pay to plan in advance for how to keep your crops cool.