7 Reasons Why You Shouldn’t Leave Your Garden Beds Empty at the End of the Season
A clean garden bed is a blank slate for the next round of planting, but it's also an opportunity to enrich soils and habitat while preventing weeds in the “off” season. If you’re giving your raised or in-ground beds a winter break, consider leaving vegetation in place, adding mulch, or sowing a crop cover for added benefits. Explore reasons to avoid a clean sweep with gardening expert Katherine Rowe.
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Weedy overgrowth, erosion, and soil compaction are just a few negative things that can happen if you leave your garden beds empty over the winter. Instead of putting the garden to bed, keep existing plants in place or add new ones to keep it alive and thriving. There are numerous benefits to leaving vegetation or adding new plants to hold down the fort during the quiet season – they provide ecological services and add a splash of green.
From dormant perennials to cover crops, plants play important roles in raised and in-ground beds during the quiet season. If you have a bare bed and want to skip planting, consider mulching to enhance natural processes. Bonus points for cool-season annuals and vegetables, including cover crops, that offer site improvements.
About Cover Crops
If you’re not planning a seasonal growing rotation or have bare earth to hold until spring, specialized plants help improve and nourish the site. Cover crops like fall-planted grasses and legumes work with microorganisms to protect and enrich soil between primary crop-growing phases. And you can turn them into organic matter at season’s end by folding them into the soil. Cover crops are quick and simple to sow and improve growing conditions in the long term.
Best of all, cover cropping is easy and does the work for us while the garden takes a break. Opt for fall seed species and scatter them evenly and generously. Enjoy the fall and winter greens with minimal maintenance aside from watering during dry spells.
Cut them back for the next round of seasonal planting before they go to seed, leaving the cut material in place or adding it to the compost pile. Cover crops also benefit pollinators in transitional seasons. Use them in raised beds for soil improvement during quiet times.
Winter kill (dieback after heavy freezes) depends on the crop’s hardiness and climate. Choose cold-hardy varieties for your USDA growing zone to get the longest growing time and the most benefits. Check the “days to maturity” on the seed packet to ensure you have enough time to sow and establish for cool season coverage. If you know a cover crop is invasive in your region, opt for one that isn’t.
Suppress Weeds
By their very nature, weeds adapt to varying conditions, including the cool weather of fall, winter, and early spring. Whether lying dormant as overwintering seeds or popping up as fresh, spreading stems, weeds are waiting in the wings. Having vegetation in place helps reduce weedy spread.
Cover crops, planted densely, offer effective weed management through competition and suppression. The seasonal crops create “living mulch.” They grow closely together and cover an area quickly. The roots and leafy uppers inhibit weedy growth through matting, crowding, and shading.
The catch-22 is that some cover crops have weedy, aggressive growth. While we want this quality in contained seasonal beds, the best management is to control their spread after they flower. Mow or cut back spent blooms to prevent reseeding.
Enrich the Soil
Healthy soils are the foundation for a good yield of leafy growth, blooms, and fruits in the seasons to come. A clean, empty bed lacks extra organic matter that, in the process of breaking down, adds nutrients to the surrounding soil.
Decaying organic material makes the earth more rich and fertile. Essential micro and macroorganisms process the biomass into valuable nutrition. Plants absorb the nutrients through their roots as growth resumes in the spring, and the cycle continues.
For bare areas, consider topdressing with mulch as an organic layer. Dropped leaves and leaf mold create excellent in-house mulch and soil conditioners.
By providing resources for microorganisms, cover crops support nutrient cycling and nitrogen fixation for plant and soil health. Leguminous cover crops like vetch, peas, clover, and beans aid in nitrogen fixation. Their roots support beneficial bacteria that live in the soil. They absorb nitrogen from the air and convert it for plant uptake. Grow a leguminous crop for an entire season to create nitrogen to benefit future plantings.
In addition to increasing nutrition, cover crops retain soil moisture through their roots. Plus, incorporating faded cover crops into the bed at season’s end makes them organic matter for added nutrition.
Support Pollinators
Life in the garden continues in winter, even if it’s less visible. With a supportive habitat, the creatures that inhabit our gardens in spring and summer remain nearby, even if more hidden and less active.
The fall and winter landscape is an important habitat for native bees, butterflies, and moths. These overwinter and lay eggs in fallen leaves and hollow stems. Amphibians, invertebrates, songbirds, and small mammals overwinter in the shelter of standing plants, logs, brush piles, stone walls, and healthy soils.
Some herbaceous perennials, like echinacea, coreopsis, monarda, Joe Pye weed, and rudbeckia, form hollow stems and dried leaves that become nesting cavities for native bees and other insects. Ornamental grasses are a haven for birds and small mammals for food and shelter.
Minimize Erosion
There’s a balance between cutting back herbaceous perennials to prevent fungal disease and leaving woody specimens standing. Leaving selections in place without cutting back may reduce runoff. It also helps form a natural snow fence or break.
Roots and leafy growth protect surface soils against harsh winter conditions, especially in windy or sloped sites. Cover cropping is a good method for preventing soil loss due to erosion. It reduces runoff, soil splash from rains, and drift from winds. Keeping surface soil intact promotes a healthy overall structure.
Utilize Leaves
Fall’s natural leaf drop benefits beds by providing insulation, moisture retention, weed suppression, and nutrition through decomposition. Fall leaves are an ideal mulch, compost, and soil conditioner.
The leaves also provide ecological benefits, such as shelter for beneficial insects like swallowtail butterflies, luna moths, and stick insects who nest, lay eggs, and overwinter among them. Leaving the leaves is a pollinator-friendly practice.
If you have excess leaves, pile them to become leaf mold for future soil enrichment and mulching. It takes about six months to completely break down leaf material, but leaf mold is easy to make and a valuable resource for amending native soils at planting and topdressing.
Improve Soil Structure
Cover crop roots create channels to help aerate and improve soil structure. They retain moisture and prevent excess drying. Decomposing plant parts, too, aerate and reduce compaction.
Use cover vegetation as part of the planting rotation. Crop rotation is especially helpful in vegetable gardens or when growing the same family in bulk. Nightshades like tomatoes and peppers, for example, or cucurbits like cucumber and squash, benefit from not being planted in the same spot for a few years. They share the same soil-dwelling pests and diseases.
Cover crops help mitigate pests and diseases by mixing up the rotation. They’re not immune to pests, though, and may attract their own.
Minimize Maintenance
We’re accustomed to tidying up, cutting back, and removing debris from raised and in-ground beds. If we adjust our aesthetic in the name of boosting soils, supporting pollinators, and suppressing weeds, we may realize less maintenance over time. Seasonally, we’ll spend less time raking and gathering leaves. Mulching and keeping existing vegetation in place is the path of least resistance.
Cover cropping is a quick and easy way to keep bare beds healthy, though it does come with maintenance considerations. Prior to spring planting, plan for removal. Let the material die out naturally by winter kill or smother it with tarps or cardboard. Cut or mow it down, especially right after flowering, to prevent seed production. Or, pull it and add it to the compost pile.
Useful Cover Crops
There is no need to leave your garden beds empty when you could quickly scatter cover crop seeds instead. Popular cover crops for fall include legumes (those top-notch nitrogen-fixers) like clover, beans, peas, and vetch. Grasses like annual rye, oats, winter wheat, and buckwheat make for fast-growing coverage.
Have leftover seeds from the autumn veggie garden? Kale, radish, and turnips make excellent crops for improving aeration.
Prepare the bed by removing vegetation and mulch and smoothing it with a rake. You can also sow while late-season veggies grow and produce by sowing around them. Scatter seeds generously for dense coverage.
Crimson Clover
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botanical name Trifolium incarnatum |
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sun requirements Full sun to partial shade |
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height 12-36” |
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hardiness zones 6-10 |
Crimson clover provides a valuable service as a leguminous cool-season ground cover. These upright growers have a taproot that fixes nitrogen. One-inch-long red flowers appear in spring and attract beneficial insects.
This frost-tolerant ground cover is hardy to -10°F (-23°C). It grows over the winter as a cool-season annual in zones 6 and warmer. Sow seeds six to eight weeks before the first frost date for best vigor.
Fava Beans
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botanical name Vicia faba |
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sun requirements Full sun |
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height 30” |
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hardiness zones 2-10 |
Small-seeded favas are a cool season annual with tall, fresh, leafy green stalks and a bushy habit. Their ample roots fix nitrogen and break up soils for less compaction.
Fava beans produce small, white pea flowers with brushed black centers. The early spring blooms draw pollinators as a valuable transitional nectar source.
Fava beans are frost tolerant and cold hardy, germinating in temperatures as low as 35°F (2°C). The vigorous legumes mature in 30 to 60 days.
Hairy Vetch
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botanical name Vicia villosa |
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sun requirements Full sun to partial shade |
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height 24” |
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hardiness zones 4-9 |
Vetch is a vigorous mat-forming legume with sprawling stems. It’s a valuable source of nitrogen and weed suppression. Even more, hairy vetch may increase disease resistance and prolong photosynthesis in following plantings.
White-to-purple tubular blossoms cluster along stems in spring, highlighting the carpet in color. It’s most nitrogen-rich at this stage and easiest to “turn” into the beds. It breaks down quickly over a few weeks before planting time.
Buckwheat
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botanical name Fagopyrum esculentum |
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sun requirements Full sun |
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height 24-48” |
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hardiness zones 2-10 |
Buckwheat is a frost-sensitive annual that grows from fall into winter in mild climates. In cold climates, sow it in early spring or late summer for a fast-growing ground cover. The plants break down quickly when incorporated as organic matter.
Buckwheat has tall stems and abundant white flowers that attract beneficial insects. The blooms appear in short order, about 35 days after sowing.
Buckwheat is another nitrogen-fixer with beneficial roots. It delivers phosphorous for future plants to develop healthy foliage and flowers.
