No matter where you live, sometime this summer your garden will swelter in a heat wave. It already feels like an oven in much of the central USA, but the rest us have time to prepare. Now is the time to tweak your garden for the hot weather to come, because few things feel sadder than watching a good garden shrivel away when it's too hot to do anything about it.
First, look at your crop list and make the most of crops with tropical temperaments like the tomato family (tomatoes, capsicum, eggplant, sweet potato), dry beans, lima beans, or even okra. My luck stops with the tomato family because of my moderate summer climate, but I find that many types of winter squash make fantastic summer crops.
Cultivars that are of the Cucurbita maxima species are especially great because they readily develop supplemental roots where the stems touch the ground, thus helping to drought-proof themselves. Above ground, the vigorous foliage shades out weeds and helps keep the soil cool on hot summer days. Popular C. maxima cultivars include 'Burgess Buttercup', 'BonBon' and 'Black Forest' and other kabocha squash.
A surface mulch of grass clippings, straw, rough compost, weathered sawdust (the list goes on) will help keep the soil cool and moist while suppressing the growth of weeds. Reducing the temperature of the soil with a deep mulch is especially beneficial to potatoes and other root crops, which generally prefer cool soil conditions. And, one of the reasons why mulching is so important to tomatoes is the moderating effect it has on soil moisture. When my soil is never allowed to dry out, I suffer but a few cracked fruits.
With crops like tomatoes that stay in the ground all summer, I like to apply mulch over a soaker hose, which can be turned on at low pressure before my sweet corn, tomatoes, or capsicum run short of water. Many crops like sweet corn have critical times when they absolutely must have water. A drought that hits when sweetcorn is tasselling can reduce yields by half. Similarly, squash and beans need moisture most when they are in blossom and setting fruit.
One of the main reasons why I mulch is that I don't want to weed and water in hot weather, if I had the time. Harvesting, preserving, and planting late season veggies has me getting up early and staying out late, leaving no time for weeds. Fortunately, a good mulch can reduce weed emergence by 80 percent and reduce watering needs by 30 percent or more, which is exactly why mulch really does matter.
Shade Covers for Vegetables
When the sun intensity ratings are off the chart and you have tomatoes and capsicum ripening on the vine, or perhaps young beans just coming into bloom, you can easily turn down the heat with shade covers made of cloth, snow fencing, window screens, or numerous other materials. Some shade covers block more light than others, so you must gauge your remedies accordingly. For example, I use a very light shade cover made from a double thickness of tulle (wedding net) to protect my peppers from sunscald, whereas I'm likely to cover a spot seeded with late squash with a cardboard box until the seeds germinate. When transplanting seedlings in hot weather, I routinely cover them with upturned clay flowerpots for two to three days before releasing them to the sun.
I also make use of natural shade screens created by living plants. Climbing beans planted at the ends of my corn rows benefit from partial shade early on, and eventually smother the failing sweet corn stalks with their exuberant foliage. Flowering annual vines can be used to great advantage, too. In my climate, thunbergia (clock vine) and cypressvine morning glory do not reseed successfully, so I often plant them on the ends of trellises used to support spring peas. There they form a summer shade screen for autumn veggies planted at their feet. Do be careful, because some annual vines including beautiful morning glories can be terribly invasive. You will never have this problem if you grow sunflowers as shade screen plants.
A friend who has too many pine trees on his property cuts little ones, sticks the bases in buckets of soil, and moves them around his garden as very natural green screen type shade covers. Gardeners are such resourceful people!
Please share summer survival strategies that have worked for you in your organic garden.
By Barbara Pleasant