Floating Row Covers: Temp And Pest Control

One summer, I came out to my back garden to find all my basil seedlings gone. I didn’t know what could have taken them out, and assumed it was insects. Later that week, I discovered the culprit was a cardinal. If only I had used floating row covers to protect my basil seedlings, I’d be stocked up on pesto right now. 

While floating row covers are great for protecting plants from birds, they’re also a useful barrier between plants and insects, or other mammals that may want to have a little snack from your garden. They’re protective in others ways too, and shield fully grown plants and seedlings alike. 

If you’re considering garden row covers, remember there are many different types to choose from made of different materials. They can be fashioned for raised beds or simply to cover plants growing in garden beds in the ground. They’re useful for both cool-season crops and warm-season crops. 

So let’s talk about floating row covers, examine types of row covers, and discuss how you can set up your own at home.

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What Is a Floating Row Cover?

Floating row covers are long pieces of fabric made of woven plastic, polypropylene, natural fiber, plastic, or polyester materials. They may be affixed directly to the earth, or laid over a structure that keeps them off the surface of plants. Using row covers can bring many benefits to the garden. My basil, for instance, could have used a little protection from the cardinal plucking little seedlings out to snack on. Some row covers are light enough that plants can still absorb moisture and light while they’re protected. All row covers create a barrier between plants and some external force that could damage them. 

How Floating Row Covers Work

Row covers have multiple functions that can occur at the same time. As you read through their uses, consider what your garden plants need. This will help you determine what kind of garden row covers are best for your home garden. 

Pest Management

Birds and insects, and mammals too, love to dig up, pluck out, or feast on seedlings and some fully grown plants. Row covers keep out many pests in the home garden. With a row cover as an insect barrier to protect plants, your seedlings get a good head start. Established garden plants that typically have to deal with a lot of pests in a season benefit from row covers, by putting a wall between them and typical pests. In this way, a floating row cover is useful if you need to protect warm-season crops, which are growing when insects are most active. This also applies to cool-season crops that grow across cool and warm seasons. 

If you’re using crop rotation to keep pests at bay, use row covers to trap them in an old bed, while you protect the new and exposed bed. Utilize them for insects that overwinter in garden soil, or lay eggs that remain in the soil in winter waiting to emerge in spring. 

If you want to trap and destroy pests within the covered rows you can plant flowers like marigolds or calendula, which they’ll be attracted to, and then place a support and polypropylene row cover over the gardens where they’ve been trapped. As they feed, they’ll be trapped and unable to seek out the flowers of tomatoes or other vegetables. Then remove the row covers and destroy the trap crop. 

Plant Protection

Just as young seedlings need a little protection from insects, row covers are also great for wind and frost protection. They can provide shade for young plants, and plants that are particularly sensitive to direct light. Row covers help new plants develop strong roots by preventing snapping in the wind. They provide frost protection for plants that need to be planted in early spring but are sensitive to cold. And they are a kind of shade cloth for garden plants. They help maintain moisture levels on warm days when a normal irrigation schedule won’t cut it. They’re also great when temperatures drop, keeping the soil warm below. 

If you struggle with both insect or herbivore damage and want to protect your plants from frost damage, a simple critter cage topped with a critter cover frost blanket is an easy solution. The blanket works like row cover, but fits securely over the cage to provide insulation from cold and block out any creatures that like to munch on your plants.

Row Covers As a Season Extender

Aside from plant protection and pest exclusion, if you want to extend the growing season, using row covers is a solution! While they’re providing frost protection, they also ensure cool-season crops can keep growing in warm weather without bolting. Cool-season vegetables – like broccoli and leafy greens – are especially sensitive to heat. A floating row cover will prevent flowering that occurs on many garden plants. Row covers also allow growers to plant crops about a week or two early, extending the season on the front end, rather than the back end. 

Floating Row Cover Types

There are three basic types of row covers. Heavy, medium, and light weight. What season you’re working in can have bearing on which row covers you choose, too. Consider the following when determining which type of cover to use.

Lightweight Covers

A lightweight row cover doesn’t require support for adequate plant growth, but it can work just as well in a hoop system. They are permeable, allowing precipitation and sunlight to come through. They aren’t great for protecting plants from frost, because they can’t trap much heat for temperature control. They are a decent shade cloth for light-sensitive plants, though. 

Mediumweight Covers

These are best for extending the season in spring and fall to help trap warmth, more so than a lightweight cover. They also shield plants from elements that may dampen yields. Root crops are especially benefited by a mediumweight cover. Two layers can do a little more than just one if you’re working in a particularly cold winter. This type of cover is permeable to light and water as well.  

Heavyweight Covers

These are the best option if you need to cover and protect plants and crops in an extended hard freeze as you would with a frost blanket. They trap warmth in a garden row when frost causes temperature dips between 4 and 8 degrees Fahrenheit. Note that a heavyweight cover will provide a lot of protection for the soil and the plants growing there, and can increase temperatures quite a bit in direct sunlight. That’s why you should remove this fabric cover from your row crops when the sun rises. Too much heat can cause blossom drop on certain spring and fall plants. Tomato crops, for instance, can suffer blossom and fruit drop at 86 degrees and above under a heavyweight material. 

Unsuspecting Row Covers

If you don’t have polypropylene or polyester fabric and supports lying around there are other options! Use items you have at home, like greenhouse plastic, old sheets, a tarp, or old towels and blankets. In the cold seasons, sow your crops under large plastic bins that have small air holes. Provide supports in the form of wooden stakes, sturdy branches, or dowel rods – though, supports aren’t necessary. Remember that you will need to remove plastics as soon as the sun rises so the plants within don’t cook. The other covers listed here should also be removed from direct sun, but they won’t trap as much heat as plastic. 

How to Set Up a Floating Row Cover

Determine which crops in your garden will benefit from covers. Then purchase the appropriate materials. Remember that row covers used as a shade cloth should be a light weight garden fabric. A row cover used to trap heat to help fall season crops survive multiple seasons should be a thicker medium or heavyweight garden fabric. Certain brands that sell garden fabric focus on one thickness, while other brands might have a wider array of row covers to peruse.

Your floating row cover can be laid directly on the ground and the edges affixed with stakes, fabric staples, or heavy bricks or stones. Alternately, they can be set up over PVC piping, in low tunnels, or over a larger frame or support structure. If you’re using row cover to protect fruit trees from intense sunlight, temperature fluctuations, or bugs, they can be draped over the tree and tied at the trunk. 

If you want hoops over your gardens, purchase material to create them so the fabric cover can sit above the row. Wooden sticks or branches that are bendable are useful in this regard. PVC piping is also an excellent choice and will hold up longer over time. In the case of using PVC, note that you will need rebar posts or strong rods that can fit within the piping about 8 inches above the ground. They should also be long enough to be driven deep into the garden soil next to your row crop. Space them a couple of feet apart on each row, and across from one another on either side. 

After you drive the rods in, ensure they’re secure, and then place the PVC piping over. 10 feet of piping creates large hoops over the crop that allows for good air circulation but also can trap warmth if that is what you need. There’s room to try different lengths of piping if 10 feet is too much. Then drape your garden crop cover over and secure it to the piping with PVC clips. Pull the rest of the fabric cover tightly and secure the base edges to the perimeter of the garden bed with heavy objects or landscaping fabric staples. The draping of the fabric is best done with multiple people. When the piping is removed, place something brightly colored over the rods to ensure no one gets hurt in the garden. 

If developing your own row covers isn’t appealing to you, there are plenty of premade options. If you’re growing vegetables in raised beds, consider a raised bed frost cover, which includes a frame that sits over the edges of the beds. Cover single plants with pop-up crop protectors. Alternately, consider a planket, which is great for container-grown plants like tomatoes, small trees, and shrubs. This cover is made of non-woven material and has a cinch cord at the bottom so you can drape it over trees in an orchard row and tie them at the base. Plankets are best for covering plants in cold weather. Finally, there is the option to buy a frame, which acts as a support for a row cover where you drape polypropylene or some other woven material fabric over your plants. 

Row Cover Maintenance

Premade options are great, but every row cover requires maintenance. Because a row cover is made of material that can trap heat in direct sunlight, it protects plants, but it does not block out weeds. So you’ll need to remove your row cover occasionally to remove weeds underneath. Another thing to consider is repairing the row cover material after using it for a few seasons. Unless it is a heavy-weight material, it will degrade over time in direct sunlight and the elements. Supports may also need replacing after a few years. Take some time each season to check your covers and ensure they have the integral structure you need to protect your plants. 

Frequently Asked Questions

Q: Do floating row covers work?

A: It depends on what you need them to do, and what type you purchase for that purpose. If you need them as a frost cover, use something medium weight. If you need them to shade plants, use something lightweight. See above for more types and uses!

Q: What can I use instead of a row cover?

A: You can use old towels, blankets, a tarp, greenhouse plastic, a plastic tub, or old sheets. 

Q: Are row covers worth it?

A: They certainly are. Because they provide multiple forms of protection at once, look into how to secure your own!

Q: How much earlier can you plant with a row cover?

A: Certain crops can be planted a week or two early. 

Q: Can I leave plants covered all day?

A: It depends on the season and the type of cover you’re using. In an arctic winter, you likely can leave any cover on. In snap freezes, remove heavier covers as soon as the sun rises.