Cover Your Raised Beds For Winter (Benefits & Method Explained)

Preparing the garden for fall and winter is an important task, but it can be challenging to know what needs to be done and when especially if this is your first year gardening. One question that often comes up is whether or not raised garden beds need to be covered during the colder months.

Raised garden beds will benefit from being covered in the winter to prevent soil erosion, build up organic matter, and prevent weed seed germination. To cover a raised bed, you can use organic materials such as mulch or cover crops or rely on a physical barrier such as silage tarps or black plastic.

Each method has some benefits and disadvantages, but no matter which one you choose you’ll be that much closer to having prepared flower beds ready for spring planting.

For more tips on winter garden prep, check out this episode of my podcast, Organic Gardening For Beginners.

3 reasons to cover raised beds in winter

Covering your raised garden beds for the winter will help protect them from erosion and weed growth and aid in creating organic matter. These benefits will help build a healthier and more productive raised bed garden that supports plant growth, giving you a summer season of bounty.

1. Prevent soil erosion

One of the main benefits of covering a raised bed in winter is that it helps to prevent soil erosion. Erosion can occur when the wind and rain strip away the top layer of soil, damaging plants and affecting their growth.

When the topsoil of a garden starts to thin, it becomes difficult for plants to grow in because they can’t get the nutrients they need from the soil. Additionally, the plants’ roots can’t anchor themselves properly. This can lead to dead plants, bare patches in the garden, and washed-away beds if your garden is on any kind of slope.

Think of covering your raised beds like tucking your plants in at night: warm, secure, and protected from the elements.

2. Stockpile organic matter

Another main benefit of covering a raised bed in winter is that it helps build up organic matter in the soil if you use organic materials such as mulch or a cover crop.

Organic matter comprises decomposed plant and animal matter such as leaves, plant roots, dead bugs, and microorganisms. It is essential for healthy soil, both for the nutrition it provides and the structure it builds.

Organic matter helps to improve the texture of the soil, makes it easier for plants to grow in, and increases the amount of water that the soil can hold. If your garden has excessive sand or clay, these are particularly impactful benefits.

By adding organic matter to the soil, you feed helpful microorganisms and insects that balance your garden’s ecosystem. Organic matter is one of the most significant parts of creating a balanced environment for plants, microbes, and other organisms that aid in plant health and growth. 

Did you know you can also build organic matter by repurposing your old plants? Read how to do it in this article, You Should Leave Dead Plants In The Garden For Winter (Here’s Why).

3. Prevent weed seed germination and growth 

A major downside of leaving a raised bed exposed in the winter is that it can lead to an influx of weeds come springtime. Weeds can quickly take over a garden, and they can be difficult to get rid of if they’re allowed to establish themselves.

You can prevent weeds by covering your raised bed in winter. Mulch is the most common method, but this article will also discuss other options such as cover crops and tarps.

Mulch is a protective layer of material that is spread over the soil. The mulch prevents light from reaching the weed seeds in the ground, which stops them from germinating. You can also use a physical barrier such as a silage tarp, a heavy-duty, UV-resistant tarp that easily covers bare or weedy soil.

Both methods of covering your raised beds will save you enormous effort and time in the spring when you don’t have a garden full of weeds to remove before you can even get to your spring planting.

What to use to cover raised beds

These are some of the most popular options for covering raised beds, used by flower farmers, vegetable growers, and even some home gardeners like myself: mulch, cover crops, and silage tarps or plastic.

Each material has distinct characteristics that make it the best choice for your garden.

Mulch

One of the easiest ways to cover your raised beds is to apply a layer of mulch 3-4 inches deep to the soil surface. Mulch is made up of organic materials such as shredded leaves, straw, or wood chips which are spread over the garden soil.

Get some ideas for organic mulch in this article, Best (Free!) Organic Mulches For The Home Garden.

It acts as a buffer between the soil and inclement weather, keeping the topsoil in place and helping to prevent erosion. Mulch also helps keep the soil warm in winter, and it will add organic matter to the earth as it decomposes.

To increase the value and benefit of a mulch cover, first spread a thin layer of compost, then cover it with your choice of mulch. The compost will help speed up the decomposition process through the introduction of microorganisms and, together with the mulch itself, will provide a steady stream of nutrients to the soil.

If you or someone you know has chickens or rabbits, the spent bedding is an excellent winter mulch. The bedding contains straw and manure that can protect the garden soil while simultaneously breaking down and adding nutrients and organic matter to the soil.

Come spring, your plants will have an abundance of fresh compost to sink their roots into.

One downside of mulch is that it can be a magnet for pests looking for winter weather protection, such as slugs and snails. Be on the lookout for these invaders and take steps to control them if necessary.

Cover crops

Using cover crops is a more advanced way of protecting your garden for winter because of the planning needed. Still, it can be a valuable tool to crowd out weeds, add organic matter, and build soil fertility without fertilizers. 

Cover crops are plants grown specifically to cover the soil for a few months, then be cut back. Some common types of cover crops are winter rye or buckwheat (grasses), legumes such as vetch, or clover.

Cover crops are sown during the late summer or fall once your summer garden plants have been harvested and removed. They grow during the fall and winter, and once they have matured or bloomed, they are cut back in the spring to clear the soil for planting.

The cut vegetation can be used as mulch (known as “chop and drop”), and it, along with the roots still in the soil, will add nutrients to the soil as they decompose.

It takes some practice to get the crop selection, planting, and cutting times down, so read up on this method if it’s the route you take. This video from Growfully with Jenna is a great introduction to cover crops for a home garden.

Silage tarps or plastic

If you live in an area with severe winters, using a silage tarp or plastic to cover your raised beds may be best. Tarps are also the best solution if you have overgrown weeds that got away from you during the summer.

You can put down a layer of cardboard first and then tarps. The cardboard will kill the weeds and start to compost, along with the weeds, while the tarp will block light and keep rain and snow off the soil for the winter season. If you don’t have cardboard or you want to skip this step, the tarp will still be effective.

You can also use a sheet of black plastic to cover your raised beds. Plastic is much cheaper and more readily available than tracking down tarps.

It’s vital to use black plastic to block the light. Clear plastic would act as a mini-greenhouse and encourage weed seeds to sprout, keeping them warm and protected all winter.

If you’ve never heard of silage tarps, Josh Sattin’s video is an excellent resource. He’s using them for his small farm, but the basics still apply to a home garden with raised beds.

How to choose the best material for you

There are several variables to consider when selecting the right coverage for your garden beds. Things like the climate, the materials you have available, and your level of experience should all be considered.

Cost

You can stick with free options, such as collecting leaves from your yard, or you can buy materials like a large tarp to cover your beds. Silage tarps are specially designed tarps that small-scale farmers use to protect their beds when not in use, but they’re more expensive than other options.

Ease of use

Some methods, like using a mulch or tarp, are straightforward tasks. Spread material out over your bed, weigh it down if you’re using the tarp, and you’re done.

On the other hand, planting a cover crop requires more work and planning but can be more beneficial in the long run. If convenience is a significant factor, then buying bags of wood chips at the garden center may make the most sense for you.

Effectiveness

A silage tarp is very effective at blocking light, preventing weed seeds from germinating. It’s thick, so rain won’t penetrate it to saturate the soil all winter. However, it doesn’t add any value to the soil like mulch and cover crops do. Your garden priorities will help you decide which method to use.

Availability

Some options are free and found right at your doorstep, such as leaves from the trees in your yard. You can almost always get free wood chips from tree trimming services in your neighborhood if you call and ask. You can also buy bagged mulch at your local garden center.

Other options, such as tarps, are not as common, so you might have to shop online or call around to find them locally.

Climate

Your climate may influence the best material to cover your raised bed.

If you live in an area with a lot of rain, using a tarp may be the best option because it will help prevent the soil from being waterlogged all winter. Or, if you live in a cold area, using a thick layer of mulch will help keep the soil temperature up and prevent damage to any perennials you may be overwintering in the garden.

Ultimately, the best way to cover your raised beds in winter is to find a method that fits your needs. A combination might even be the best for you. It’ll take some experimentation, but once you find the right cover for you, it’ll be worth the effort.

When to cover your raised beds

Fall is one of the best times to cover your raised beds as you transition your garden from summer crops and harvest to the lull of winter. If you’re growing a fall garden, you’ll need to consider that in your planning.

Not sure about a fall garden? Read more about planting one in this article: Extend The Harvest: How To Start A Fall Garden.

Clear your garden of spent summer crops and relocate them to your compost pile where they can start the next process of their life cycle. Or, you can do a “chop and drop” and leave your plants in place as long as they don’t show any signs of disease.

This is easy to do with plants that are past their prime such as bolted greens, wormy radishes, or worn-out flowers. Tougher plants like tomato vines and pepper plants are better off in the compost pile since they’ll take a while to break down entirely.

If you are putting a layer of compost down before the mulch, it is better to start in early to mid-fall for the compost to have time to start breaking down before the first frost.

Cover crops can be planted in the late summer to give them time to grow before winter slows them down. Silage tarps can be placed whenever convenient, whether it’s right after your last harvest or later during the transition to winter.

The most important thing is that you winterize and cover your garden as soon after the growing season as you can so that weeds don’t have the time to crop up. 

Need some soil supplies while you’re preparing your garden beds? Here are my top 3: