The long summer days are winding down, putting an end to the gardening season. There’s still a nip in the air. It's clear that preparing your metal raised garden bed for winter should be a priority. 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 temperatures return.
Here are what you can do with your raised garden beds during fall:
Task 1: Remove Weeds
Weeding remains a crucial task well into autumn, even after most crops have ceased growing. For sections of your raised garden bed overwhelmed by weeds, covering them with black plastic or a layer of cardboard through the winter can effectively suppress existing weeds and prevent new ones from sprouting. Additionally, thoroughly inspect the soil of your raised garden bed, meticulously removing any clover, purslane, chickweed, or other weeds. Pay special attention to weeding any other raised beds that might remain empty during the winter. Removing all weeds ensures that nothing can germinate during the colder months. When pulling weeds, ensure that the entire root is extracted to prevent them from regrowing in spring. Use a spade or a specialized weed tool to gently loosen the soil around the weeds, which helps in removing them without disturbing buried weed seeds or snapping the roots.
Task 2: Clear Up Spent Plants
After the initial frost hits, it's essential to remove any spent and decomposing plant materials from your raised garden beds. Begin by clearing out remains of seasonal plants such as squash vines, tomato plants, and sweet corn stalks. Doing this not only tidies up your garden but also prevents the soil from being smothered by decaying plant matter over the winter, which can attract pests and harbor diseases.
While healthy plant remnants can enrich your compost pile, any plants affected by mold or blight should be removed entirely from the garden to prevent disease spread. These should be disposed of securely, either by adding to the municipal waste or through safe burning if allowed.
Additionally, some hardier crops like carrots and kale might continue to grow and even become sweeter post-frost. However, it's crucial to harvest or remove these plants before the soil freezes to avoid the unharvested material from becoming garden waste.
For plants that are disease-free and where minimal soil disturbance is desired, consider cutting the plants off at the soil level, leaving the roots in place. This method helps minimize disruption to the soil structure and microbiome in your raised garden bed but may require more time than simply pulling up the plants.
Task 3: Protect Perennials Plants
Fall pruning and protection hold the key to the health and productivity of perennial plants in your garden.
Perennial Herbs
Herbs like sage, chives, thyme, and oregano are quite hardy and, if well-protected, can continue to be harvested throughout the winter months. To protect these herbs, consider using mulch or a cold frame to insulate them against frost. When snow covers the garden, it's best to pause harvesting and wait until spring. This dormant period can help the plants rejuvenate and come back stronger in the growing season.
Hardy Greens
Kale and other hardy greens can successfully overwinter in metal raised garden beds. To enhance their survival through cold weather, apply a thick layer of mulch around the base of these plants. Mulching helps regulate soil temperature, retains moisture, and provides nutrients as it decomposes.
Perennial Vegetables
For vegetables like Jerusalem artichokes and asparagus, mulching serves a dual purpose. It not only protects the crowns from freezing temperatures but also allows for continued harvesting of Jerusalem artichokes during the winter months. Ensure the mulch is loose enough to allow for air circulation yet substantial enough to provide insulation.
It's important to trim back any perennial plants that are susceptible to rotting or fungal diseases such as powdery mildew. Plants like phlox, monarda (also known as beebalm), and peonies should have their stems and leaves cut back to minimize the risk of disease spreading from decaying plant material to the soil. This also tidies up the garden, reducing shelter for pests over winter.
Task 4: Plant Cover Crops
Cover crops guarantee your garden’s health during the winter by preventing erosion, suppressing weeds, and enriching the soil with organic matter. However, the selection of cover crops is worthy of note as some types may die back in winter while others could survive and become invasive. Winter rye, buckwheat, legumes, and mixtures of peas and oats are popular cover crops for raised garden beds. It’s best to plant these seeds well before the first hard frost—typically at least a month in advance—to ensure they establish themselves. Always check the specific germination needs on the seed packet because some seeds require warmer temperatures to germinate effectively, while others can tolerate cooler conditions.
Task 5: Add Mulch to Insulate Soil
Mulching is crucial for maintaining soil integrity, reducing erosion, and preventing nutrient runoff. When you apply organic mulch, such as straw, sawdust, or wood chips, you also enhance soil fertility. Utilizing readily available yard materials like grass clippings, autumn leaves, pine needles, or pine cones can be an economical mulching choice. In urgent situations, layers of cardboard or newspaper also work effectively as mulch. Applying mulch not only helps control weeds in spring but also protects the soil over winter. If you're not using cover crops, cover your soil to keep amendments from leaching out, which is especially important in raised beds that typically have quicker drainage than ground plots. After the ground freezes, lay several inches of mulch to protect against the freeze-thaw cycles that can damage plant roots and disrupt soil structure. Adequate mulching also shields your garden beds from harsh winter winds that might erode soil or introduce weed seeds.
Conducting these tasks will prepare your garden well for the colder months and enhance its productivity for the next season, ensuring a thriving start in the spring.