As with shade cloth, make sure to keep the sheet attached to a structure held above the plants rather than just tossing it directly on them, since this can actually transfer heat and damage small plants. You can clip or tie your repurposed linens onto a frame, poles, or a cage that arches over your garden beds. Both flat and fitted sheets should work, and you can even float pillowcases over your small container plants. This approach is great for helping summer crops, and it can also be useful in late summer when you're trying to get cool-season, fall vegetable seedlings established. Shade cloth, like many gardening products, is usually made from synthetic plastics, and can introduce harmful microplastics into your soil as they degrade over time.