Using Shade Cloth
Though the onset of summer equates to the most inhospitable part of the growing season, gardeners may be surprised to learn that methods still exist enabling the continuation of their favorite cool-season crops. In addition to spring season extension, where crops start early, and fall season extension, where crops grow later, a third method of season extension exists—where cool-season crops can grow right through the middle of summer, utilizing a garden tool known as shade cloth. Like a row cover, but more pigmented and with an overall goal of protecting from heat damage rather than insect damage, shade cloth is a simple tool that enables many growers to enjoy those crops prone to burning, bolting (premature flowering due to heat stress), or bitter flavor (a taste change caused by high temperatures) well in the summer months. So, how is it used?
Gardeners should begin by understanding that the types of shade cloth typically range from 20% to 70% opacity, and the degree of shading provided by a fabric can spell the difference between a light dappling of shade and a complete shield from the sun. Most cool-season crops carried through the summer will need extra protection to resist scalding or bolting. Thus, a 30% to 50% cloth is ideal.
Next, gardeners should know that the cloth can’t simply lie on top of the plants, as this may create other issues, such as broken limbs or smothered plants. As with mesh netting for wildlife protection, cloth row covers, or plastic low tunnels, shade cloth needs a supportive structure to rest on, and low tunnel hoops are ideal for this purpose.
However, the shade cloth structure does not stop at this point, as there are a few other essential factors. The cloth will be prone to flying around in wind and weather events, making it necessary to secure it properly. Ideally, this should be done with bricks or sandbags over landscape staples, which are likely to tear the sometimes-pricey fabric.
Proper attention should be paid to garden airflow, as a lack of airflow leads to increased humidity, promoting disease with increased moisture. Just as all life forms need water to thrive, so do the fungi, viruses, and bacteria lying in wait to infect plants, and so, shade cloth should never be a permanent structure.
In addition to removing the cloth during harvesting and watering, gardeners should closely monitor the conditions underneath and adjust as necessary. Not managed carefully, the enclosed environment could rapidly create sauna conditions, literally steaming plants to death. For this reason, both the amount and timing of water application should also be watched.
Finally, remember that while shade cloth can be beneficial, the plants protected are still technically full-sun specimens, ideally needing 6+ hours of direct sunlight daily. While this rule can be bent during summer heat, the plants should still be watched for signs of legginess or chlorosis. If either occurs, it’s likely the plants are receiving too much shade within their structure, and adjustments to the system are needed.
By following these tips, you’ll be enjoying those leafy greens for months to come, with fresh salad ingredients well into the future.