Big, juicy sweet peppers are at high risk for sunscald, which happens when hot sun burns a patch in mature green fruits. In research plots bell pepper yields under 30 percent shade increased by 50 percent, in large part because of less sunscald. When it comes to growing peppers in hot summer areas or in a greenhouse or tunnel, leafiness, fruit set and fruit size all improve with light shade, and sunscald is reduced to almost nothing.
Timing is important, because you don’t want to slow peppers by shading them too soon. Let the plants grow uncovered until the soil is warm and the plants start blooming and setting fruit, and then install a shade cover. I use a piece of 30 percent shade cloth secured over the peppers, but you also could use a panel of row cover or an old sheer curtain as a shade cover for peppers. Either will reduce light transmission by about 20 percent.
