How to Use Floating Row Covers for Your Garden
Floating row covers are versatile tools made from spun-bonded or woven plastic, polyester, or polypropylene materials. They help protect plants by excluding pests, serving as windbreaks, and extending the growing season by retaining heat. These covers allow light, water, and air to pass through, ensuring healthy plant growth.
Pest Control with Row Covers
Floating row covers are an effective barrier that prevents many pests from reaching plants, reducing the need for chemical interventions. They are most effective when placed immediately at planting to block pests from laying eggs or feeding on crops.
Here are some pests that can be managed with row covers:
- Caterpillars (imported cabbageworm, cabbage looper, diamondback moth) on cabbage, broccoli, and cauliflower
- Flea beetles on cabbage, potato, eggplant, and salad greens
- Onion maggots on onions
- Seedcorn maggots on beans, corn, and other crops
- Cucumber beetles on cucurbits during the early season
- Thrips on various plants
- Aster yellows disease (transmitted by aster leafhoppers) on carrots, celery, lettuce, and flowers
Since some pests, such as flea beetles and seedcorn maggots, emerge from the soil, it’s essential not to trap these pests beneath the cover. Crop rotation can prevent infestations by reducing the chances of recurring pest problems. Additionally, row covers used over insect-pollinated crops like cucumbers or squash should be removed during bloom to allow pollination.
Extending the Growing Season
Floating row covers can also act as season extenders, providing frost protection and creating a warmer microclimate for crops. Depending on the cover’s thickness, plants can gain between 2-8 degrees of frost resistance. With proper placement—such as on a south-facing slope—harvests can begin earlier or continue longer into the fall.
Types of Floating Row Covers
There are three main categories of floating row covers, each designed for specific uses:
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Lightweight Covers: Ideal for protecting crops from wind while allowing full airflow and sunlight. These covers offer minimal temperature increase but are affordable and easy to use without supports.
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Mediumweight Covers: These covers retain some heat, helping to speed up crop growth. They are useful for extending the growing season during cooler months and work well with crops like lettuce, peas, radishes, potatoes, and blueberries.
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Heavyweight Covers: Providing up to 8°F of frost protection, heavyweight covers are perfect for early or late-season use. They are particularly beneficial for warm-season crops by raising daytime temperatures. However, be cautious with heat-sensitive crops like tomatoes and peppers, which may experience blossom drop if the temperature exceeds 86°F.
How to Use Floating Row Covers
When using floating row covers, lay them directly over flexible, low-growing crops, leaving some slack to allow room for growth. If using them for pest exclusion, bury the edges to block insects from getting underneath.
For taller crops or plants with delicate leaves, such as spinach, consider draping the cover over a framework made from bent PVC pipes to prevent abrasion.
To harden off plants, remove the covers gradually, preferably on cloudy days. Store covers away from direct sunlight, as UV exposure can degrade the material.
Maintenance Tips
Floating row covers can also promote weed growth under their protective environment. Regularly remove the covers to eliminate weed seedlings. While row covers are typically not used for ornamental plants due to their appearance, they can be beneficial early in the season for starting seedlings or temporarily protecting valuable plants.
Where to Buy Row Covers
Floating row covers are available at large garden centers and from specialty mail-order catalogs. Their versatility makes them a valuable addition to any gardener’s toolkit, whether for pest control or extending the growing season.
