Planting cool-season crops poses a challenge when the weather is still hot, but there are tools you can employ to protect plants that don’t tolerate the heat.
Once plants are in the ground, apply a layer of about two inches of mulch over the bare soil around the plants, then water it in. Organic mulch — such as shredded leaves, arborist’s wood chips, or straw — will maintain soil temperature and retain moisture.
The next step is to provide the plants with a light amount of shade. An easy, low-tech method is to use floating row cover, a spunbond nylon fabric that is often known as Reemay. Floating row cover allows air, water and adequate light to pass through while blocking pest insects, such as cabbage moths whose caterpillars prey on cabbage, broccoli, Brussels sprouts, kale and other cool-season brassicas.
The small amount of shade that row cover provides will go a long way to keep the temperature around the plants lower than the air temperature outside the cover. Row cover is light enough that it can be laid right on top of growing plants. Just be sure to anchor it down so it doesn’t blow away.
But here’s something to keep in mind: If you have the option to suspend the row cover above the plants, with hoops or some other support, that can be a safer option for your plants on those really hot days.
Row cover is also good at trapping some heat, which is why it is often used over plants during frosty weather. However, if that row cover is resting directly on your plants during hot weather, the heat can be too much for the tops of tender foliage just beneath and can result in mild to severe burning.
For a safer route, and even more shade, I like actual shade cloth. Shade cloth is an inexpensive and durable nylon mesh available in different weaves that provide varying degrees of shade. Unlike floating row cover, shade cloth is too heavy to lay right on top of plants and needs to be supported. This is easy with some inexpensive PVC pipe.
Use a ½ -inch PVC pipe for about every 3 feet of width in the garden bed. A 10-foot length is about $3 and can be cut down shorter with a hacksaw or PVC cutting tool if needed. Bend each pipe into a “U” shape, and install them by pressing the ends firmly into the soil.
Drape the shade cloth over the top of the hoops and make sure there is full coverage from front to back. I find it easiest to start by clipping one end of the shade cloth to the top center of an end hoop, then doing the same on the opposite end after pulling it taut. Then continue adding clips and pulling out the slack as you work your way around the bed.
Shade cloth won’t block all of the sunlight but, depending on the weave, it will block about 70 percent of the light, which is enough to give young plants relief on hot days.
If you haven’t watched the video on protecting cool-season crops in hot weather yet, you can scroll up to play it now
How do you protect cool-season crops from the heat? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener Online Gardening Academy™: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!
joegardener Online Gardening Academy Essential Gardening Fundamentals: The basics on healthy soil, planting, watering techniques, composting, raised bed and other gardening methods, fertilizer, the many benefits of mulch, and more.
*Disclosure: Some product links in this guide are affiliate links, which means we would get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us. None of the items included in this list have any bearing on any compensation being an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, Milorganite, Soil3, Park Seed, and Exmark. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.