10 Tips for Preparing your Raised Garden Beds for Winter

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Tips for Preparing your Raised Garden Beds for Winter

Winter can be a trying time for gardeners. Not only does winter weather reduce the amount of time you can spend outside, it can also wreak havoc on your carefully maintained raised beds!

When it comes to getting through the winter with your raised beds still intact, preparation is key. Leaving it until the first frost before you start to think about the garden will come back to bite you next spring.

It’s even more important to protect your raised beds than traditional ground level beds. As the bed is exposed to the cold air on all sides, the soil will cool down faster. Throughout the autumn, you should take steps to ensure your raised beds are protected when the cold weather hits. 

Not sure where to start? We’ve put together the perfect winter raised bed to-do list!

1. Remove Weeds


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The first thing you should do when it comes to preparing your raised beds for the winter is remove weeds that have managed to become established. 

Weeds that are left in the beds throughout the winter can harbour diseases and make the issue even harder to tackle later down the line. 

Give your raised bed soil a close inspection and pull out any visible weeds, taking care not to leave any roots behind. 

If there’s a large number of weeds in your raised beds, you should cover the soil with a plastic sheet. Leave the sheet in place over the winter and it should stifle the weeds. 

2. Remove Dead Plants

Annual flowers which have died and any other diseased plants can be removed from your raised beds in late summer. 

Try not to disturb the soil when pulling annual plants out of the flower beds, especially if you’ve got perennials growing alongside. 

Dead plants can be used to make compost or mulch for the following year, unless you have experienced any issues with pests, in which case they should be thrown away. 

If your plants have signs of disease, such as powdery mildew, they can be thrown onto an active compost pile. The heat should eliminate any lingering diseases. 

3. Remove Stakes and Supports

If you’ve got stakes and supports in your raised beds, they can be removed and stored indoors at the end of the growing season.

Other delicate structures such as garden ornaments can be stored away over the winter. 

With the right care, these structures can last for years, so it’s important not to expose them to prolonged periods of rain, snow or strong winds. 

Now is also the time to inspect your garden tools for damage and give them a good clean. Once dried thoroughly, they can be stored away for the winter. 

4. Add a Layer of Compost


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 Now is the time to give your raised beds some TLC! The soil will likely be in need of more nutrients following a productive growing season. 

After clearing the beds of weeds and dead plants, gently rake the surface of the raised bed, being careful not to disturb the soil underneath. Add around 4 inches of compost to the top of the raised bed. 

The compost that you add in the autumn will break down over the winter, leading to a fresh and fertile raised bed that’s ready for spring planting. Don’t mix the compost in, as you don’t want to disturb the soil underneath. 

5. Plant Cover Crops


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 Many gardeners choose to plant cover crops for the winter season. These can revitalise and improve the soil in between plantings. The seeds are sown into the raised bed to help prevent weeds. Once the cover crops have died off, the debris is turned into the soil to form a nutrient-rich compost. 

Good examples of cover crops include fast-growing, cool-season crops such as buckwheat, alfalfa, clover, rye and radishes.

Autumn is the best time to plant cover crops, allowing you to make the most of the time when the beds would otherwise be empty. Once all the plants and perennial weeds have been pulled from the bed, sow the seeds of the cover crops and allow them to germinate and grow.

In the winter, many of the cover crops will go dormant, while others will be killed off by the frost. At around 50-80% bloom, the cover crops can be cut at the base using shears. Place the plant debris on the soil surface and they will gradually decompose.

After a few weeks, the raised beds will be ready for planting. The cover crops should have broken down to form a rich, healthy soil. 

6. Add a Layer of Mulch


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 If you’re not planning on using cover crops, adding a layer of mulch to the soil should have a similar effect. This will improve your soil, helping it to retain moisture. Mulch can also help to moderate the soil temperature. 

Good types of mulch include straw, woodchips, shredded leaves, bark and grass clippings. Ensure the mulch is free from disease and pests before applying to your raised beds. 

Spread a 2-3″ thick layer of mulch over the beds. This will break down and decompose, enriching the soil with nutrients as it does so.

7. Protect Perennial Plants

Some perennials can be harvested all winter provided they are given adequate protection. Otherwise, leave them as they are and they’ll return in the spring. 

If you’re growing perennials in large pots, these can be moved to a sheltered location during heavy rainfall, strong winds or frost. You could move them inside, or place them against walls, fences or other plants. 

If you’ve got a larger raised bed that can’t be moved, it’ll need protecting in other ways. To start, ensure your beds have adequate drainage. 

Tender plants can be protected by adding a layer of mulch over their roots. This will slowly rot, providing the soil with nutrients and helping it to retain moisture. 

8. Cover Plants with Burlap

One of the biggest dangers to your plants in the winter is frost. A cold spell can kill even hardy plants if they are not adequately protected. 

Raised beds tend to lose heat earlier on in the autumn as the soil is exposed to the cold air from both the top and the sides. This is why it’s important that you take steps to protect your plants from the winter season early. 

Burlap or fleece can be used to keep your plants warm during cold weather. Burlap is durable and natural, and can keep plants warm without stifling them. Fleece is usually made from polyester and helps to insulate plants. 

To cover your raised beds, you should first cut the fabric to the right size. You can either cover individual plants or your entire raised bed. 

When covering individual plants, tuck the fabric around the plant, loose enough to allow for some air circulation. Secure it in place using string or rocks. 

9. Insulate the Soil

Freezing weather can harm and kill plants and crops. While you can protect your plants by moving them to a sheltered area, there’s a couple of ways you can keep the soil insulated too.

Hot composting is a very effective way of protecting plants from cold conditions. This has two benefits. Firstly, the warm temperatures will help keep the soil warmer when frosty weather hits. And second, the compost will add valuable nutrients to the soil.

Keep your compost heap as warm as possible by surrounding it with leaves, straw or other organic material. If you have a bin or container, covering it with a tarp will help keep the warmth in.

10. Amend the Soil


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 Adding soil amendments in the autumn can make all the difference the following year. While raw organic matter (such as compost or mulch) can be used to improve soil health, there’s a couple of simpler options. 

In the autumn, you’re likely to have access to fallen leaves. Make the most of this readily available organic material by spreading the leaves onto your beds. This can help stifle weeds and slowly release nutrients to improve the soil.

Another great addition to raised bed soil is perlite. This is a 100% organic substance made from volcanic glass. Perlite will lighten the soil to improve its drainage, which can help stop the soil getting waterlogged in the winter. Perlite will also help the soil to dry out faster, meaning it warms quicker in the spring, giving you a jump start when it comes to spring planting.


Do I need to cover my raised beds in winter? 

This does depend on what you are growing. If you are planting cover crops, there’s no need to cover your raised beds. These can be grown throughout the winter then killed off, with the foliage left in the soil to break down.

Otherwise, you may want to consider covering the raised beds with either mulch or a man made material. Fallen leaves make a great covering material, and will slowly break down. A layer of leaves can protect the soil from very cold temperatures. 

Covering your beds with tarp, a plastic sheet, burlap or horticultural fleece is recommended if you’ve got less hardy perennials which need protecting. 

What should I plant in my raised garden bed for winter? 

Cold-resistant vegetables are the best choice for the winter months, and allow you to make the most of your raised beds year-round. Vegetables that can be planted in the autumn and harvested in the winter include radishes, rocket and spinach. 

Are raised beds warmer than in-ground beds?

On sunny days, raised beds do tend to warm up faster than traditional in-ground beds. However, they also get colder in the autumn.

The reason is that the soil is exposed to the air temperature on all sides, as well as from above. This means they lose heat faster, but they also warm up faster in the spring. 

This is also because raised beds tend to have much better drainage than in-ground beds, thanks to the improved soil quality. Better drainage means the soil dries out faster, which will allow it to warm quicker too.

Of course, the rate at which your raised beds warm up and cool down will depend on the height and size of the raised bed, as well as the materials used to build the bed. Many gardeners use a liner which can help to improve insulation. 

How do I keep my raised bed from freezing? 

During very cold spells, the soil in your raised beds can freeze, which can damage your plants. 

Protecting your raised beds from frosts begins at installation. Ensure your raised bed is built in a spot where it receives at least 6 to 8 hours of sunshine. During sunny spells, the soil will warm, and covering the bed at night can keep the warmth in. 

You should consider a lining for your raised bed before you add the soil. Thick plastic liners can help to insulate the soil against extreme temperatures, while also preventing weeds from growing up into the bed. 

If frost is predicted, it’s recommended that you water your plants. Damp soil can hold up to 4 times more heat than dry soil. Keep your plants hydrated, and they’ll be less susceptible to frost damage. 

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