A row cover tunnel is a simple way to extend the growing season and protect plants from cold, wind, hail, insects, wildlife, and more.
Since there are many uses for a row cover tunnel in the garden, there are also many different materials to use and ways to do it.
In this blog article, we share the ones we use. All DIY using readily available materials.
For a row cover tunnel, you need a row, a cover, and a tunnel. Sounds simple right, so let us take it to step by step.
What to protect and why?
First, let’s look at the plants we want to protect. It can be a single row, garden bed, raised bed, or even a vegetable patch. Any area that grows plants and needs protection.
In spring we might want to protect a row of early lettuce from frost. Then we might want to protect a bed of strawberries from birds. As soon as cabbage butterflies are flying, we want to protect cabbage plants from them. If carrot flies are bugging our carrots we want to keep them out. And we are living in a hail area, so protection from hail is a priority.
As you see, there are so many reasons for protection. We haven’t even mentioned deers, squirrels, cats, and dogs.
And yes, for most of it a simple row cover tunnel will do. Adding protective netting is a much better solution than using pesticides that can harm all insects and also the bird population.
You can cover 2 or 3 rows with one tunnel. Ideally, you want to be able to access the plants from both sides of the row cover tunnel.
Covering a whole patch with one cover is an option, but after having the experience we would not recommend it. Since our main reason for that particular cover was to keep deer and moose out, we thought it would work. It did keep them out, but also us to be able to weed under the cover. After that experience, we have become more interested in row cover tunnels instead.
Covering at most 4 feet at the time is a better idea. And also using hoopes for the cover is easier and more effective.
What covering to use
The covering material very much depends on its function. Even though a protective blanket can be used for about everything, it is not the ideal cover for everything.
For frost and wind protection we want to use a thicker fabric. Frost protection blankets come in different densities. The more dense ones give more protection, but also make more shade. In our garden, we usually have different frost protective blankets. My preferred place to buy them is the Dollarama store. But any hardware store or garden center usually carries them.
We use frost protective blankest as a row cover but also in the row cover as an additional protection layer.
Plastic might first come to mind when thinking about frost protection. Even though it is true that plastic would create airtight protection, it is also true that that brings a real danger of overheating as soon as the sun comes out. So personally we rarely use plastic and only use plastic with open ends. And since there is no wind inside, we add a protective blanket for additional protection if needed.
Netting or mesh is a great option for protection against insects. The density depends on the insect you want to keep out. For carrot flies, the netting needs to be very fine.
Here I used IKEA lace curtains that are lightweight and inexpensive. The protection however was not perfect. Maybe adding hoops would have brought better results.
Since we are also gardening in the hailstorm alley, we have since started using hail protection netting. It is much stronger, in protects from hail, wind, and also insects. Here is a side-by-side comparison picture. The floating row cover did not hold up in a hailstorm.
Any dense netting will give some wind and intense sun protection.
For plants that need protection and pollination use netting that can let through pollinators. Bird protection netting is a great option to keep birds and most predators out.
For some reason, deer do not like flattering netting. Even though they could easily get into it, they usually don’t.
Bird netting is available in about any hardware or garden store in different sices and densities. In our experience it is not very durable, so choose the best price you can find.
The size of the netting depends on your garden bed and plant. Many nettings come 7 feet wide, it works great for a 4-foot bed.
The length needs to be as long as the bed, plus the height of the tunnel and some extra material to be able to enclose the bed if that’s what you are going for.
Hoops for the tunnel
The hoops for the tunnel can be made out of different materials. The strength of the material will depend on where it is used and what cover is it for.
For bird netting or light-weighted cover galvanized vire 9-gauge works great. To be able to straighten it and cut we fastened it in a bench vise and cut it with side cutters aka diagonal cutting pliers.
In a very windy area and for heavy cover you want stronger material. If you have access to a 4- or 6-gauge galvanized wire, that’s a great option.
We have repurposed Spiral Tomato Cages, since they aren’t the best option for tomato support. Straightening them with a hammer, and bending them to a U-shape around a plastic barrel, they make good hoops for a row cover.
1/2 or 3/4 inch PEX pipes are probably most commonly used. To fasten the hoops you can place metal stakes into the ground and slide the pipe ends over them, or you can push the pipe ends into the ground.
We have used rebar stakes with good results.
Fastening the pipes to a garden bed board is an option, in most cases for a small hoop, it is not needed.
Running a ridge pipe or rope is a good idea if you plan to use heavy cover material, or if the hoop are higher or bigger. For most netting covers it is not needed.
The length of the material for the hoop depends on the width of the bed and also how high you want the hoop to be. Keep in mind that some of it will go into the ground for stability.
For example, for a 7ft cover use a 7ft pipe, that way you can push about 6 inches at each end into the ground and also have an overhang of the netting to secure to the ground.
Securing the cover
To secure the cover tight is important. A cover that moves in the wind can bring more damage to the plant than no cover. Also, you don’t want loose netting flattering around to be a trap for birds and small animals.
The cover can be clipped to the pipes and or fastened to the ground. From simple clothespins to special garden and heavy-duty pins, all are useful in one way or another.
We often use boards. In a windy area, the material can be rolled up to the board, so the wind has no way to grab on to it.
Rocks are another simple option. Since we use covers so much, our garden has rocks everywhere.
Personally, we do not use ground pegs or stakes. They cost extra and wind can easily rip the material off of them.
In commercial settings, sandbags are often used. If you have no boards or rocks available, making sandbags is a great idea.
For hail netting, hand-made clips work well. They can be made in two versions.
Start with cutting a pipe one size larger diameter then than the hoop’s pipe into about two-inch pieces. Make one cut lengthwise. Now by holding one side of the cut between two metal plates heat up the material with a heat gun. As soon as the plastic has been heated form it to make an opening as shown in the picture above so that the clip can be easily secured on the hoop.
Another option is to do two cuts, removing about a quarter of an inch. Round the corner with a knife, so it does not rip the cover material.
Both versions work, and there might be more options like cutting up a short piece of a garden hose.
Just use what is available and what works best for you.
Tell us about your row cover tunnel experience. Maybe you have already upgraded to a caterpillar tunnel, same idea, just bigger and stronger.