What are row covers and how do they work?
Row covers are one of the best tools gardeners can have. They are a great way to keep pests out and extend the growing season, both in the spring and fall. Row covers are spun-bonded or woven material such as plastic, polyester or polypropylene. These materials allow light and rain to penetrate, but keep pests out, block wind and retain heat.
There are three main types of row covers: lightweight, mediumweight and heavyweight. What’s the difference?
Lightweight row covers are the least expensive and are used mostly to protect plants from garden pests and strong wind. Because they are so light, they don’t need support. The fabric can rest directly on the plants, which will push the fabric up as they grow. Sunlight, rain and air can all move through the fabric to nourish your growing plants. Garden pests, such as moths, won’t be able to penetrate the fabric and lay their eggs on the underside of leaves however. That makes lightweight row covers ideal for crops such as cabbage, broccoli and cauliflower, which are susceptible to these pests.
The row cover pictured above is a lightweight fabric from Gardener’s Supply Company. They have three types of row covers: all purpose (the one I chose), summerweight and gardenquilt. I chose all purpose fabric row covers for this area of the garden because I simply want to keep pests out. We planted a row and a half of cabbage in this bed. After witnessing the devastation caused by cabbage worms earlier this year on the broccoli, I’m not taking chances.
Gardener’s Supply Company’s all purpose fabric is a point-bonded polypropylene fabric. It transmits 70% of light and can protect plants from frost damage with temperatures down to 28 degrees (-2 degrees C). They offer the all purpose fabric in three sizes, but you can also use scissors to cut the fabric to fit your space.
I cut the excess fabric from the sheet I purchased and used it to cover two more cabbage plants in another bed.
While lightweight fabrics, like Gardener’s Supply’s all purpose fabric, do not need supports, I chose to add some. You can purchase hoops, but what’s the fun in that? I like to repurpose things and in this case, I used pool noodles and a hoolahoop to make garden hoops. Watch the video to see how I used them as hoops. I thought it added some nice color and a bit of fun to the garden. The kids also got a kick out of it.
Here’s a sneak peak of the first pool noodle placed in the cabbage row. The row is 29 feet long and I used three pool noodles and one hoolahoop cut in half. You can choose how many hoops you’d like to use, or simply lay your lightweight fabric directly on your plants.
Mediumweight Fabric Covers
If you’re looking for help speeding up the growth process, mediumweight fabric covers might be for you. They retain more heat than lightweight fabric covers which helps extend the growing season in both spring and fall. It works best in the fall however as the ground is already warm. This is a great choice if you are growing blueberries, carrots, peas and lettuce as well as potatoes.
Heavyweight Fabric Covers
Heavyweight fabric covers are usually made of spun-bonded polypropylene and can protect plants from frosts, down to 4 degrees (-15 degrees C). They transmit about 60% of light and are used in late fall and early spring to extend the growing season. Many gardeners use heavyweight fabric covers for strawberries and small fruit. These fabric covers can raise the temperature underneath an additional 10 degrees above the external temperature. Less light and water penetrate this type of cover however.