As hints of frost nip the air, preparing a raised bed garden for winter should be at the top of your mind. A little maintenance and late fall or early winter garden care can keep soil healthy while giving you a jump start on spring planting when warm temperatures return.
Keep reading for a to-do list for what to do with raised garden beds in winter.
Remove Annuals and Vegetables
Pull annual flowers and spent vegetables, such as squash vines, tomato plants and sweet corn stalks, as you're preparing your raised bed garden for winter. It's much easier to accomplish in the fall (versus a muddy spring) and keeps your soil free of rotting foliage over the winter.
You can leave root vegetables, such as carrots and potatoes, in the ground until just before frost or freezing temperatures.
Trim Back Perennials
Trim back stems and leaves that can get soggy and rotted over the winter. This is especially important for plants such as phlox, monarda (aka beebalm) or peonies that might have powdery mildew that spreads into the soil.
Removing foliage can also prevent problems from pests such as iris borers, which may lay eggs in the foliage.
You may wish to leave some stems with seed heads, such as echinacea (aka coneflower) or coreopsis, to feed winter birds. Some gardeners also like to leave decorative grasses over winter to shelter birds and wildlife.
Clear Out Weeds
Creeping Charlie, dandelions, thistles, plantains and other weeds can encroach on your garden. Before winter, remove weeds along with the thousands of weed seeds that may propagate in your garden.
Make sure you get the root of the weed, or it will keep growing in the spring. Pull weeds gently (you may need to loosen the soil around them with a spade or weed tool) to avoid loosening weed seeds or breaking off the root.
Add and Nourish Soil
When the soil is cleared of plants, the next step in preparing a raised bed garden for winter is to assess the soil level. With new gardens in particular, the soil can sink in the first year. Add a few inches of fresh soil if needed. Even if your soil level stays steady, also add an inch or two of well-rotted compost.
Compost helps fortify and nourish your soil for growing the best plants possible in the spring. If you think your soil needs a fresh infusion of garden fertilizer, that's another task to include on your list for what to do with raised garden beds in winter.
Plan Ahead With Bulbs
Mulch to Insulate Soil
One of the most important tasks in preparing a raised bed garden for winter is insulation. Above-ground gardens can be more vulnerable to the cold than in-ground gardens. Keep your soil covered with several inches of mulch. Spread the winter mulch after the ground is frozen. If you have deciduous trees, a layer of fall leaves easily does the trick and costs nothing. You want enough mulch to insulate the soil and plants from damaging freeze-and-thaw cycles during the winter. Good mulching also protects your raised beds from winter winds that can blow away valuable soil or blow in unwanted seeds.
Shelter Your Portable Gardens
If you have portable raised beds, move them into a shed or garage for the winter. That protects them from the winter elements and helps materials last longer. You can also tuck them next to a garage and cover them with a tarp. Keep the tarp anchored with rocks, bricks or wood to keep it from blowing away during winter storms.
Expand Your Gardens
If you want to expand your gardens, carve out time to build or install new raised bed gardens. Corner components make it easy to put together square or rectangular raised beds with cedar planks. Spend the winter dreaming about flowers, vegetables and fruits for the new bed until spring arrives!
For more information on raised beds, check out Burpee's guide to raised bed gardening.