Yesterday was the beginning of our Persephone Period here in Northern Virginia. The daylight hours have dropped to below 10 hours per day and will stay that way until January 25 next year. With the reduction in daylight hours, it’s getting colder out there, but my gardening season isn’t done yet. This winter, we’re performing a garden experiment that involves continuing the growing season through the winter months. As part of that experiment, we need to protect our plants from the coming frost, and possibility of snow. Frost covers are an obvious choice. But why buy something pre-made when we have resources around the house and the skills to put those resources to work? That was the inspiration for this garden project.

What is a Frost Cover & Why DIY?

Every gardener knows frost can damage or even kill your plants. Essentially, a frost cover is a means of protecting your plants from cold air in the autumn, winter, and spring. Frost covers go by many names: frost blankets, row covers, plant covers, floating covers, or garden/plant cloches.

There are a lot of different varieties out there on the market for purchase. But many of these options can get pricey. As such, I like to DIY as much as I can. Plus, it’s much more fun.

DIY Frost Cover Planning Phase

Before starting any DIY project, it’s important to plan things out to minimize expenditure of time, resources, and money.

First, I considered the materials I would use. There are essentially two parts to DIY-ing a row cover for plants: The hoops and the cover itself. But as I discovered during my project, there was a little more to it than that.

The Frost Blanket

The most common frost blankets are a woven mesh of plastic and/or cloth that is both lightweight and relatively transparent. Lightweight material is important as your plants will be able to receive water and nutrients from outside through the mesh. Transparent is important because it allows sunlight through to the plants’ leaves.

For a full DIY approach, a lightweight, light-colored bedsheet may provide enough of both ventilation and light. For my own frost blanket, I didn’t have a bed sheet I was willing to part with. So I decided on a one-time purchase of a floating row cover made of polypropylene mesh. The company I trust is Burpee. The Burpee floating row cover cost a little more than $30 USD after taxes and shipping. It’s reusable and will last for years.

Note: we are not affiliated with or sponsored by Burpee. I just thought you’d like the link.

The Hoops

Next up is the hoops of the frost cover. You can lay a bedsheet or a purchased frost cover directly onto the plants, if it’s not too heavy. However, some plants, including very young seedlings, won’t be able to support even a lightweight covering on their own. Hoops offer a skeletal support to the frost cover so that the material doesn’t weigh down the plants. It also allows a cushion of air between the frost blanket and the colder air beyond. This way top leaves aren’t directly in contact with the frigid air.

Hoops can be made out of lots of different materials. The most popular DIY material to support a frost cover is PVC or metal. But those materials invite a host of problems. I don’t have the ability to cut the PVC or rebar and bend it so it holds its shape. I also didn’t want to hurt myself in the process.

Standard wire hoops that support low row covers use 9-gauge wire (0.114 inch diameter or 2.91 mm). These wire frames can span a distance of 2 feet and 18 inches tall. For the smaller raised beds that I have on my patio, I don’t need to cover as much area. So a smaller gauge wire will support the frost cover that my plants need.

Since the frost cover I’d chosen was not particularly heavy, I realized that there was a true DIY option. Most of us literally have this item hanging around the house: wire clothes hangers. Common wire clothes hangers are made of 12-gauge wire (0.081 inch diameter or 2 mm thick). The ones I gathered to use for my DIY project are exactly this size.

Side Note for True Winter Climate Gardeners

It’s worth mentioning that wire clothes hangers may not be up to the task in your neck of the woods. Where I live in Northern Virginia, I’m not expecting to contend with much snow. So I don’t have to worry about the weight of snow collapsing my row covers. In northern climates, you should use sturdier materials that will be able to take on the weight of an unexpected (or even expected) snowfall.

Staying Power: How to Get the DIY Frost Blanket to Stay in Place?

Frost covers need to be lightweight, let in light, but heavy enough not to blow away in the inevitable wind. In ground, you can use rocks or bricks on the edges of your frost blanket. As part of my container garden, my intention was to weigh it down with the raised bed itself. However, I worried that placing weight on the edges alone wouldn’t be enough to hold the frost blanket in place on the hoops.

Some companies sell clips that are designed to hold frost covers to the hoops themselves. I looked into this option for my frost covers, but for a DIY project, it felt a little like giving up. So, I decided to put my sewing skills to the task instead.

The polypropylene mesh that I’d purchased was thick enough that it can be sown like any fabric. A simple tunnel fold, such as in curtains for curtain rods, seemed easy enough to accomplish with a couple hours’ work. Here’s the pattern I drafted for my own frost cover hoop sleeves:

In my blueprint, I added slits in the sleeves about a third in from each side. This is because I intended to use this cover on my raised beds on my back patio. I need to keep the heat in on the top. But I also need to make sure heat isn’t escaping through the sides of my plant beds, either. The slits allow the wire hoops to exit the sleeves early to stick into the soil of my raised bed. The excess frost cover material will then drape down to protect the sides of the container.

Plan in Place, Time to DIY the Frost Cover

Now that I’d drafted a plan of attack, it was time to put the plan in action. The steps I needed to complete when constructing my DIY frost cover were:

• Measure the amount of real estate the frost cover has to … well … cover.
• Sew the sleeves in the frost cover for the wire hoops.
• Straighten the clothes hangers into lengths of wires.
• Assemble the pieces together.

Measure Twice, Cut Once

Every project begins with measurement. This project was no different. I measured my raised bed for the exact dimensions I needed. Then, I laid out the floating row cover on the floor and transferred the measurements to the cloth. Once I was sure I had everything right, I went to work with my trusty pair of fabric scissors.

(As anyone who has ever made sewing a hobby knows, always keep a dedicated pair of scissors for cutting cloth. Never use them for anything else – especially paper, which dulls scissors faster than almost any other material.)

On Pins & Needles

If you’re looking to stick the landing on this, pay heed. Because you’re dealing with such a large volume of fabric, you need to pin things in place before you sew. Otherwise, even the slightest deviation while you’re sewing will result in an askew sleeve that won’t fit properly.

I decided on a roughly 1/2 inch sleeve for my clothes hanger hoops. That meant I needed to add that dimension to the overall frost cover length before cutting. 3 clothes hanger hoops at 1/2 inch sleeves made of folding the fabric 3 times meant 0.5 x 3″ x 3″ or an additional 4.5 inches added to the end of the fabric. As mentioned above, measure twice, cut once.

I spent the next hour or so pinning the fabric so that it would stay in place when I sewed. Difficult, but highly necessary.

Sew Much Fun

Now that I had my pins in place, it was time to sew the tunnel sleeves. I decided on a clear plastic invisible thread that wouldn’t show any lines. This made elegant seams in the polypropylene mesh. After a few issues with the sewing machine, I had my three tunnel sleeves in place. (I’m still not sure how the sewing machine continued to function after the thread completely slipped off the thread guide)

Serious Multi-Pliers

I first thought that I would have to cut the curved and twisted parts of the clothes hangers before I could straighten them. But as it happened, I didn’t need the wire cutters at all. Two pairs of heavy duty pliers was all I needed to sufficiently straighten things out.

Frost Cover, Assemble

After threading the extended clothes hangers into the tunnel sleeves, it was time to cut the slits in the sleeves. This allowed the wire to exit the sleeves and stick into the soil. The rest of the frost cover would then drape around the raised bed. Given that the raised bed was 12 inches high, and there was about an inch or so of distance between the inside of the box and the outside, I figured 18 inches was appropriate overhang to allow space to tuck underneath the raised bed to prevent it from blowing away.

Once I made the slits, I inserted the straightened clothes hangers and my frost cover was ready to go.

Note: the polypropylene mesh that I used for my frost cover doesn’t require hemming. Its edges won’t fray like cotton, linen, or burlap. If you’re using a fabric that frays, you’ll need to take that into account. A bit of hand-sewing may be required to prevent the fabric from unravelling.

Installation time!

My husband helped me move the entire rig out to the garden patio. With four hands, we were easily able to install the full frost cover over the kale.

Because the frost cover lines the entire top and outside of the bed, the air temperature on the inside of the box will be 5 to 8 degrees warmer than the outside air. Plus, the frost cover will protect the plants from the worst of the wind’s desiccating effects. Meanwhile, light and water will still be able to get through the mesh to nurture the plants. Win-win!

Final Product

I hope you enjoyed reading about this project as much as I enjoyed doing it. It’s always so gratifying to watch a blueprint that you created come to life. If you tried this out for yourself, be sure to leave a comment and let us know!