Crop Cover (Row Cover) is a Gardener’s Best Friend

Crop Cover (Row Cover) is a Gardener’s Best Friend

            In Horticulture, row cover (or Crop Cover) is any material used to cover plants as a protective shield primarily against cold and frost.  It is also used to protect against wind, rain, snow, sun, bird and insect damage.  American Nettings’ row cover is called Crop Cover, not to be confused with cover crops, which are vegetative crops that are planted to protect soil from wind and water erosion in between planting of a cash crop.  Crop Cover is know by many different names including: frost cover, row cover, frost blanket, frost protection, reemay, garden fabric, non-woven garden fabric, spun-bonded fabric, over-winter fabric, plastic row cover, plastic mulch, field cover, and floating row cover.

Crop Cover acts as a protective greenhouse that keeps plants warm and guards against frosts, while allowing sunlight and moisture to pass through.  This creates all the perfect conditions to increase the growth of your plants and produce bigger, better and earlier crop yields.  There are many different types of Crop Cover.  The three main Crop Covers (or row covers) that we will discuss are non-woven spun-bonded fabrics, plastic row covers, ribbon-knitted shade covers.

Non-woven Spun-bonded Fabrics:

The most commonly used Crop Cover is the non-woven spun-bonded fabric. Fabric Crop Covers are lightweight blankets made of spun-bonded polypropylene which is sunlight, rain and air-permeable.  American Nettings carries a lightweight and a medium weight crop cover.

The Medium crop cover weighs .9oz/yd (30gm).  It has a 70% light transmission and is UV Stable.  It protects from frosts down to 26°F and has a life expectancy of 2 years.  It’s great for extending the growing season by planting early in the spring and continuing to grow and produce late into the fall.  They also makes and excellent wind break for young transplants.  This row cover is ideal for over-wintering strawberries, herbs, small fruits, tender landscape plants and just about any perennial.

The Lightweight spun-bonded crop cover weighs .5oz/yd (17gm).  It has a light transmission of 85% and protects from frost down to 28°F.  Its life expectancy is 1 year.  The light weight crop cover, also know as floating row cover, is great for promoting seed germination.  Lightweight crop cover can be used all season long to defend some crops such as carrots or onions against birds, insects, harsh rain and light hail.  Other crops that require germination such as squash and tomatoes should be uncovered as soon as they start to flower.  In hot climates Crop cover may have to be removed to prevent excessive heat build up.  Lightweight can be double layered in the spring to have the same effects as the medium wt and then a layer can be removed when it warms up.

Non-woven Spunbonded Fabric

Non-woven Spunbonded Fabric

Plastic row covers: 

Plastic row cover is made out of clear plastic (polyethylene).  This type of Crop cover must be carefully managed because it is much less forgiving and more labor intensive then fabric covers.  Temperatures under plastic can be as much as 30° higher then the outside air.  You can Vent them on warm days and close them at night and on cold days.  Plastic row covers that are slitted don’t require venting but you also can’t close them up at night.  For those gardeners that live in Warmer Southern areas can use Colored or shaded plastic.  The coloring blocks out some of the sunlight, reducing the heat inside the tunnel.   Plastic cover should be suspended over the plant and not touching the delicate foliage

Plastic crop cover

Plastic crop cover

Ribbon-knitted Shade Cover: 

Knitted shade cover is made from High Density Polyethylene (HDPE) and is a knitted fabric. It is strong and can last up to 8 years. This material comes in different shade effects from 20% to 90%.  When used as a row cover less shade effect is desirable.  If there is too much shade the plants will grow slowly. This product is forgiving in that it allows natural airflow and rain and water penetration unlike plastic. It also protects from light frosts, strong winds and hail. It will not hold as much heat in as the fabric cover but it will allow excess heat to vent better then plastic.  Works great for warmer areas that are more concerned with protecting plants from sun rather the protecting plants from cold.

Ribbon knitted shade

Ribbon knitted shade

Crop Cover is Easy to Use:

Crop Cover is so versatile. The possibilities are endless.  A whole book could be filled with technique for using Crop Cover.  Lets talk about three easy ways to use crop cover in the garden.  One way is to create a Crop Cover tunnel over rows.  The Second technique is to drape Crop Cover over a trellis row.  The third way is to use crop cover as a floating row cover.

A protective tunnel formed with row cover is sometimes called a cloche. More often, a cloche, or bell jar, refers to a covering made of glass or plastic, placed over individual plants to provide similar protection as row cover.  You can make the tunnel supports with Just about any material such as 9-gauge wire, rebar and wood.  My favorite hoop material is 1” PVC pipe.  It’s strong, lightweight, inexpensive and easy to get.  Pound a 2’ piece of rebar 1’ in the ground and leave 1’ sticking out on either side of the row.  Slide one end of the PVC pipe over one rebar.  Then bend and push the other side of the PVC over the top of the other rebar.  Voilà, You have your first hoop.  Repeat this process every couple of feet all the way down the row.  Suspend the Crop Cover over the hoops and you have a tunnel.

Crop Cover Tunnel

Crop Cover Tunnel

Drape Crop Cover Over a Trellis Row:

Urban gardeners to grow on trellis rows in order to produce more in small spaces and to get higher yields per plant then growing on the ground.  It just so happens that trellis row is perfect for draping Crop Cover over.  You don’t have to do any extra work. The trellis itself becomes the framework for the perfect little microenvironment under the Crop Cover.  Drape the Crop Cover over the top wire of the trellis and pin the bottoms o the ground like a tent formation.  Easy as Pie.

crop cover trellis row

crop cover draped over trellis row

Floating Row Cover:

The first two techniques are great but I’m a big fan of keeping things simple and over the years I have come to realize that there is always stupidly simple technique for doing just about anything.  For Crop Cover this technique is called floating row cover.  You can cover newly seeded beds or transplants with light to medium weight fabric crop cover.  Leave plenty of slack in the material to allow for growth.  Seal and secure the edges and leave it alone.  The plants will grow and lift the crop cover up with them as the go.  That’s what I call low maintenance.  There is no need for elaborate structures or hoops, which leaves more time for the good stuff in life.

crop cover directly over plants with no supports

crop cover directly over plants with no supports

 Secure the Edges:

No matter which technique you use you must secure the edges of the Crop cover in order to seal in the warmth and moister as well as to seal out the sneaky birds and insects.   Bury the edges to make a seal.  Then you must secure the edges from being blown up by the wind or burrowed up by pests.  You can use any number of materials that you have lying around the house such as brick, rocks, 2×4 and old tires.  You get the drift.  Be careful because rock with sharp edges can tear the fabric and let unwanted guests in.  One really clever way that I have seen is to fill old water bottles with water and lay them around the edges of your fabric.  My favorite way technique is to pin down the fabric with plastic fabric pins from American Nettings.  The pins have a loop handle on top, which makes it so easy to push them in and take them out when you need to work with your plants.  You can use them year after year and they are not very expensive.  They also help your garden look neat and tidy verses looking like a bunch of debris blew in on a windy day.

Handling Crop Covers (row cover)
Working with fabric row covers may seem awkward at first.  Lightweight fabric tends to blow around while you’re putting it in place on windy days. The fabric can also tears easily on sharp edges.  But, with a little time you will get the hang of it.  Here are a few tips:

  • The fabric can be cut with scissors to fit over rows or used as-is for wide-row plantings.
  • You can purchase Crop cover in small convenient pieces or you can buy large roll and continue to cut off of that same roll year after year.
  • At the end of the season, shake the covers to loosen dirt and debris, and make sure they’re dry before you put them away. Fold or roll them up and store them in a clean dry place
  • Save all the cut or torn pieces of cover, cut them up into small pieces for patching larger sections of cover that have small holes. You can use waxed dental floss to sew them.

Conclusion:

It’s rare to find gardeners that are satisfied with the length of the growing season.  Luckily, Crop cover can provide a solution for the irresistible urge to go out and start planting as soon as possible.  Crop Cover fabric is a good tool for all gardeners because it is versatile and has an extremely low cost and huge benefits. Spun-bonded Crop Cover Fabric is the favorite choice.  They create a barrier that keeps the wind, cold and pests out, while allowing water, air, sunlight and soluble fertilizers to pass through. Wow!  They can increase your production as much as 25% while decreasing your labor and stress.  That’s why the commercial growers use it so much.