Weeks ago I wrote about Cold Frames, the sturdy method for growing vegetables in the deep of winter. Today I will talk about their movable cousin, row covers.
Modern row covers are a lightweight fabric made of spun polypropylene. They are made in various weights for different applications, such as frost protection, insect protection, and light infiltration.
Heavyweight row covers are used for frost protection and can hold about 8 degrees above the ambient temperature. They are thick and therefore do not let as much light through as their lightweight counterparts, but provide superior protection in the cold.
Lightweight row covers can be used for light frost protection, but are better utilized for pest control during the summer. The row cover acts as a barrier between your crop and the insects searching for them. This is incredibly useful for eggplants, of which get annihilated by flea beetles when they are young. The fabric is light enough to not cause huge temperature increases in the summer as a plastic row cover would.
It is important to note that row covers are often called "frost blankets." During a nighttime frost, water in the air condenses on the ground, and then freezes due to the temperature. This is what causes frost damage on your crops. The row cover over your crops becomes the "ground" in which the frost settles, saving your plants.
Row covers are incredibly useful because you can move them around your garden. I often use them early in the season to create a micro-climate for early greens and roots, then move the cover to protect my tomatoes and peppers from late frost, then move them to protect broccoli from cabbage loopers, before bringing them back to use for late season greens.
And now you know!