The plastic can be left on all season or removed prior to planting. Combining black plastic mulch with a clear, slitted plastic tunnel will raise soil temperatures enough to get melons and other heat-lovers off to a fast start. In the fall, polypropylene fabrics will retain heat and keep soil temperatures several degrees warmer. This can give heat-loving crops such as peppers, okra and tomatoes a couple extra weeks to ripen. Sun and Heat.
Hot weather can be just as challenging as cold weather.
In hot weather, young plants can be stressed and stunted, salad greens turn bitter and go to seed, and getting seeds to germinate can be very difficult. Shade netting can be laid right over wire hoops or a movable wooden frame. By reducing the amount of sun reaching the plants, it can keep soil temperatures cooler and reduce moisture loss from the foliage. A piece of wood lathe attached to a frame can serve the same purpose. For most gardeners, frost is a limiting factor in both spring and fall.