Floating row covers are useful for extending the length of your growing season (see season extension techniques for a discussion of this idea). Even during the middle of the growing season, the extra heat they provide and the moisture they retain can speed up the growth of your crops.
They are also helpful in keeping certain pests off your crops. There are many different kinds and brands of floating row covers. They come in sheets of sizes ranging in width from about 3 to 30 m (10-100 ft) and in length from 8-300 m (25-1000 ft). Some covers are made of clear plastic, and these are intended to be used once and then thrown away or recycled (if possible). Most, however, are made of a something that looks like a thin but strong white cloth (it’s actually a material called spunbonded polyester).
Some brands are thicker than others. The thicker the fabric, the more heat and moisture it traps, and the longer it will last in your garden (most row covers can be used for two to four years if stored carefully inside when not in use; at some point they have too many holes to be effective).
Buy the heaviest row cover you can find and afford.
To use floating row covers follow the instructions below. If you are growing plants from seed, start at step 1. If you are growing plants from transplants, start at step 9.