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Row covers are a great tool for home gardeners and small farmers alike, but there are a lot of options to choose from. Fabric vs plastic, lightweight vs heavyweight — which one is best for your needs? We’ll explore the answers in this article so you know what options are best for you and how to use them.
Article table of contents:
I. Why use row cover?
II. Row cover: three considerations
III. 3 tips on effective use of row covers
IV. Row cover product recommendations
I. Why use row cover in your garden?
Row covers are one of the best tools available to gardeners and small farmers. They’re a highly versatile technology that can be used to achieve a number of desirable outcomes, including:
- extending your summer growing season;
- growing cool weather crops throughout the fall and winter (in milder climates);
- warming the soil and putting summer transplants out earlier than usual to get a jump on the growing season;
- keeping pest insects off of your plants;
- improving seed germination in direct-sown crops.
Row covers are widely available, easy to use, and tend to be relatively inexpensive. In fact, if you calculate the total cost of a row cover versus the value of the crops you grow under them, you’ll likely find that they’ll more than pay for themselves after a single growing season.
Properly maintained and stored when not in use, row covers are also reusable and can last for years before needing replacement. Product longevity will vary greatly based on quality, climate, and usage frequency. General durability expectations:
- polyethylene plastic will last for a maximum of 3-5 years before becoming too brittle to use or too foggy to allow for ideal sunlight transmission;
- polyester fabric will last for 3-5 years before becoming too worn to be effective.
II. Row cover considerations
Row covers are generally constructed from either polyethylene plastic or polyester fabric. For the sake of simplicity, we’ll simply refer to these two materials as either “plastic” or “fabric” for the remainder of this article.
The tricky part is deciding which type of cover works best in your particular situation, depending on what you’re growing, your climate, time limits, and other factors. There are also considerations such as material weight/thickness and usage methods which we’ll discuss in detail below to help you figure out what type of row cover you need for your particular situation AND how to use it.
Consideration #1: Polyethylene Plastic vs. Polyester Fabric Row Cover
Polyethylene systems can get hot in a hurry since there’s virtually no airflow between inside and outside. Especially on sunny days, polyethylene plastic traps more heat faster than polyester fabric, potentially increasing the internal heat by as much as 30 degrees on a sunny mild day.
This heating effect can be mitigated somewhat with white or colored plastic, which partially blocks sunlight. Also, the heavier the cover, the more sunlight will be blocked (more on material weight below). Obviously, the more sunlight blocked the lower plant photosynthesis takes place, thus reducing plant growth.
Plastic is a better choice than fabric row cover for extremely cold climates, but it’s critical to check the covering on warm, sunny days to ensure your plants don’t bake. As a general rule, the covers should be pulled back and vented whenever temps reach 55°F or higher.
Fabric offers less cold protection, but allows air to flow freely through the fibers. It also allows in water from rain, whereas water runs off of plastic row cover. For plants growing under plastic row cover to get water, you’ll need to either pull back the plastic on rainy days or provide supplemental irrigation.
Consideration #2: Material weight
Lightweight row covers can be left in place longer and through higher temperatures than heavy covers. Although lightweight covers — either fabric or plastic — are less expensive, they are more likely to be damaged by deer hooves, boots, stakes, or wind.
Heavier covers are more tear-resistant and longer-lasting, but they also carry a higher price tag.
Lightweight (or summerweight) covers don’t provide a lot of frost protection, but they can be useful to protect plants from animals, birds, and pest insects. Extremely light weight fabric is also used in the summer as shade cloth to reduce plant heat stress or sun scald.
Lightweight fabric may be just the ticket in mild climates where nights are a little frosty but not frozen, and they may provide ample protection for cold-tolerant plants such as leeks, spinach, carrots, parsnips, turnips, swiss chard, and others. One option, however, is to apply a double layer of fabric (or a layer of fabric and plastic) in the event of an unexpected cold snap.
According to Michigan State University Extension, most polyethylene plastic and polyester fabric covers provide protection only to about 28°F, but heavier covers may protect plants when temps drop as low as 20°F.
You can choose lightweight, medium weight, or heavyweight covers depending on your needs. Packaging is marked with the levels of frost protection and sunlight transmission.
Consideration #3: Floating or tunnels: different ways to use row covers
Floating row cover
“Floating” row covers are draped directly over a group or row of plants. Because the covers are supported by the plants, the material must be lightweight. Floating covers may not be the best choice for easily breakable or tall/mature plants.
As an example, we often use lightweight floating row covers when protecting eggplant transplants from early season flea beetles. Once the eggplants are larger, better established, and therefore better able to withstand insect damage, we’ll remove the row cover.
Row covers are also used as tunnels, much like miniature greenhouses. This method is best when there’s an actual row of plants being covered, rather than just a few individual plants.
The covers are supported by fiberglass rods, wires, PVC hoops, plastic-coated steel hoops, or anything strong and bendable. The supports prevent breakage from strong winds or fabric rubbing against the stems.
As an example, we use medium weight fabric with hoop tunnels throughout the fall and winter on the rows of cool weather garden plants that we’re trying to protect from the cold. The supporting frames underneath the cover keep it from collapsing on to the plants during heavy rain or the occasional snow and ice storm.
III. 3 Tips on Effective Use of Row Covers
1. Secure the edges.
Row covers need to be secured along the edges with heavy objects such as bricks, sand bags, plastic bottles filled with water, or smooth rocks so they don’t blow off during heavy winds/storms.
Don’t use anything sharp that will tear your fabric. (Some people use landscape pins, but we think this practice is likely to shorten the lifespan of your covers.)
2. Watch for pest insects inside.
Keep in mind that any pest insects (such as aphids) that make it into the warm, protective environment under the cover may multiply quickly since predators aren’t able to get in to control their populations. (This is less of a problem in winter when pests are less active or dormant.)
Be sure to regularly check for pest insect proliferation under your row covers. You may need to use neem oil or similar products for organic pest control if so.
3. Consider pollinators.
One thing to consider is that a secure row cover effectively keeps out the bad insects, but also blocks bees and other pollinators. If you’re growing plants that require insect pollination (example: watermelons), row covers may not be the best option for pest control.
If you do opt to use row cover on insect pollinated crops, the cover must be removed when plants are blooming. Or if you aren’t ready to remove the cover entirely, open the ends or roll up the sides during the morning, when pollinators are most active.
IV. Recommended row cover products
Now that you know what type of row cover is ideal for your setup and needs, it’s time to find the product(s) to match! Check out the list of top-rated row covers in our online Amazon affiliate store. Whether you want more customizable DIY options or all-in-one kits, there’s a product to suit your needs.