Although not the prettiest to look at, floating row covers are worth their weight and more when it comes to protecting your tender vegetables from early frosts or hungry pests. In fact, the advantages even go beyond this. Recent studies indicate several additional benefits of using row covers in the garden.
Row covers are used primarily for two purposes, to provide a physical barrier for pests and to keep cold sensitive plants a bit warmer and frost free. The term ‘floating’ refers to how the actual cover is laid over the plants. The material is so light that it can simply lie on top of the plants and be secured on the edges with soil or something heavy. No additional support is provided in this case. Lightweight covers like these are used mostly for protection from harmful pests, like flea beetles and cabbage looper moths attempting to lay eggs on the plants.
This material is typically spun bound polyester that allows light and water in but keeps pests out as long as the rows are securely covered. However, these covers will keep all insects out. Some insects are necessary for pollination and proper fruit development. Therefore, when you use a cover to protect crops from pests, be sure to remove it during the daytime when pollinating insects are active around your plants, when your plants are in flower, prior to setting fruit. This usually lasts for about a week. Once you see fruit development or a decline in the flowers on the plants, you can re-cover throughout the day.
The second most common reason for using row covers is to protect the more delicate crops from light frost. When secured around the plants, these covers can add four to seven degrees of additional heat protection.
Covers used for this purpose come in different weights. The heavier the weight, the greater amount of frost protection. Unlike ‘floating’ covers, these are ‘hoop supported’. The combined weight of the frost and material can be too heavy for the plants.
Hoops can be made from a number of materials including heavy gauge galvanized wire, flexible bamboo sections, or PVC piping to name a few. All can be inserted into the soil to a depth of 12 inches or so. The material for the covers is most often clear or white polyethylene plastic. Only sunlight is able to penetrate these covers, so be sure that you are checking the plants for proper watering. Some versions of this cover have precut holes or slits every few inches to allow for ventilation.
In addition to the primary reasons listed above, university research indicates some other benefits to using row covers. Because of warmer soil temperatures and a more controlled environment, crop yields have shown to be earlier and larger, up to 25% in some cases. Covers also hold in more moisture so supplemental water requirements are less.
I’ve used row covers for years including on the set of Fresh From the Garden. They have saved my crops many times from destruction by pests and freezing temperatures. With so many options available today, they can and should be used year round. I can’t imagine not having row covers as a staple in my garden.