The long summer days are winding down hinting an end of the gardening season. There’s a nip in the air and that preparing a metal raised garden bed for winter would be at the top of your mind. Throughout autumn, gardeners with raised garden beds should carry out some maintenance and care to keep soil healthy while giving a jump start on spring planting when warm temperature returns.
It’s bittersweet. Once the metal raised garden beds are cleared, you might be thinking the gardening season is done and finished. Nevertheless, it gives your green thumbs a break for the winter. When there are no longer watering, looking for signs of pests, staking and pruning plants you have time to assess. It is a great opportunity to feed your soil, get a head start on next year, and take stock of winter project planning for spring fixes and builds.
Here are what you can do with your raised garden beds during fall:
Task 1: Remove Weeds
Weeding is essential well into the fall, even when the majority of your crops have stopped growing. For the parts of your raised garden bed that’s simply carpeted in weeds, cover them with black plastic or a layer of cardboard and leave it in place through the winter season to choke out existing weeds and suffocate sprouting weeds. Another method is to give the raised garden bed soil a close inspection, pulling out clover, purslane, and chickweed, and any other weeds lurking about, then move on to the other raised beds that may sit plant-less for the winter. All the weeds are removed, so nothing can germinate over the winter. 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.
Task 2: Clear Up Spent Plants
After the first frost, you want to start clearing spent and rotting plant material. Clean up spent plants such as squash vines, tomato plants and sweet corn stalks, as you're preparing your raised garden bed for winter. It's much easier to accomplish in the fall and keeps your soil free of rotting foliage over the winter.
Aside from the unappealing aesthetics, rotting plants can attract pests and harbor pests and pathogens. Healthy vegetation can be added to your compost pile, but plants with mold or blight should be disposed of with the household trash or burned to avoid spreading disease.
Some crops will still continue to grow and sweeten a few weeks after the frost — root crops like carrots, for example, or some leafy greens like kale — but make sure you remove the unharvested material before the ground freezes.
If your plants are disease-free and you do not want to disturb the soil, consider cutting the plants off at soil-level and leaving the roots in the ground. Cutting the plants at the soil line will also prevent additional disturbance to the soil in your raised garden bed. It is, however, more time-intensive than simply pulling up dead plants.
Task 3: Protect Perennials Plants
Fall pruning is beneficial for certain types of perennial plants, but make sure you know the care requirements for the ones in your garden. Perennial herbs like sage, chives, thyme, and oregano, if well protected, can be harvested all winter. If your raised bed is full of oregano, chives, and sage you harvest when there is no snow cover, but once it snows, just wait until spring to enjoy them once again.
Hardy greens, like kale in metal raised garden beds can overwinter. Perennial vegetables can be mulched for winter harvests, like Jerusalem artichokes, or to protect them from the elements (like asparagus crowns).
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.
Task 4: Plant Cover Crops
Cover crops prevent erosion, ward off weeds and even add organic matter to the soil in your raised garden bed during the winter. Choosing the right cover crop and knowing how to manage it is important. Some cover crops will die during the winter, but others will overwinter and may become weeds. Examples of cover crops include winter rye, buckwheat, legumes, like clover, as well as pea and oat mixes. However，you need to think about planting cover crops well before autumn. Fall cover crop seeds are generally planted at least a month before your region’s hard frost date. Check the seed packet carefully, though, as some seeds need warmer temperatures to germinate, while others don’t mind cooler temps.
Task 5: Add Mulch to Insulate Soil
Mulching helps keep the soil intact, lessening erosion, compaction, and runoff. Choose an organic mulch and you’ll be adding in some fertility as well. Applying mulch right now also means there will be far fewer weeds to pull in spring.
Classic choices such as straw, sawdust, and wood chips are always a good bet, but other free mulches in your yard – grass clippings, autumn leaves, pine needles, and pine cones would all make excellent mulches and cost nothing. In a pinch, a few layers of cardboard (or several layers of newspaper) would do the trick too. you can add them to your raised garden beds as mulch.
One of the most important tasks in preparing a raised bed garden for winter is insulation. If you are not planting cover crops, consider covering the soil to prevent amendments from washing below root level (this especially important in raised garden beds, which tend to drain more quickly than in-ground beds) or adding a layer of organic mulch. As the mulch breaks down, it also incorporates fresh organic material into your soil. Keep your soil covered with several inches of mulch. Spread the winter mulch after the ground is frozen. 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 garden beds from winter winds that can blow away valuable soil or blow in unwanted seeds.