Just because the growing season is winding down doesn't mean the work is over. Your garden has been delivering the goods for months, and now it's your turn to return the favor. Here's how to prepare your garden for winter.
An ornamental garden requires different care than a vegetable garden. For starters, you hopefully have some sort of ground protection already in place, whether it's mulch or a ground cover like periwinkle. If you have a ground cover protecting the soil, be sure to irrigate the bed well if rainfall is lacking. Water-stressed plants are more vulnerable to injury or death in winter. It's best to spread mulch after the ground freezes. This will prevent freezing and thawing which can heave out plants.
What about leaves? That depends on the situation. They actually make a good winter mulch and can overwinter butterfly larvae or eggs, so it's helpful to leave them in place. You can also use them to protect rosebushes from winter dieback. Simply stuff a chicken wire frame with leaves in late fall, then remove the frame and leaves in early spring. Two exceptions to the laissez-faire attitude: if the leaves are smothering the grass or other ground cover, or if the wind has blown them into an unsightly pile, which might be a fire hazard. In those cases, remove the leaves and add them to your compost pile or vegetable garden instead. Remember to never use any diseased leaves to protect your plants and remove the rosebush if it has disease.
In most cases, you'll want to pull up annuals after a killing frost. Allow seed-bearing flowers such as marigolds and zinnias to remain to feed birds. The same goes with flowering perennials and grasses, which add structure and interest to the winter garden and also feed the birds. The only perennials you want to cut down in the fall are those that collapse to the ground after a freeze, such as hostas, as well as any diseased plants.
The question of how to prepare your garden for winter has a slightly different answer for vegetable gardens. For starters, it's heavily weather-dependent. Most of the work begins after a hard freeze. At that point, remove the spent plant material to avoid inadvertently overwintering pests or their egg masses and to discourage diseases.
Kale is a notable exception because it's a biennial, and the roots will survive and re-sprout next spring. Do cut the stalk off, though, unless you want to experience a "rotten cabbage" smell whenever it rains or there's a winter thaw.
Once the soil is bare, it's time to make sure it doesn't stay that way. Two ways to do it: Plant a cover crop or fortify the soil with leaves.
Plant a Cover Crop
Cover crops are fast-germinating plants grown for a season, then turned over, so their nutrients are recycled into the soil. While they're alive, cover crops suppress weeds and prevent erosion from rain and wind. Once they're turned over and start to break down, the plants add organic matter, improving soil texture and fertility. The best crops grow quickly and are easily worked into the soil when it's their time.
Popular cover crop plants include oats, annual rye and legumes like beans, clover and peas. Legumes provide more nitrogen, so you can fertilize less the following growing season. Non-legumes have their benefits too, especially in soil that's been overfertilized.
They "scavenge" the excess nitrogen, using it up rather than letting it get flushed out of the soil with rain and melting snow. It's then made available the following season when the cover crop is turned over. In fact, that's the reason cover crops are also called green manure.
Fortify With Leaves
Leaves are one of nature's most underrated gifts. Sure, we ooh and ahh as they turn color in fall, but when they drop, so does our level of enthusiasm. Then they become a chore. Instead, consider how useful leaves can be when preparing a garden for winter. Shredded leaves make a fine mulch in ornamental and edible gardens — and they're not as prone to blowing away in dry weather. Leaves can also be a great resource for vegetable gardens.
For quickest results, dig leaves into the soil. Most leaves will break down into humus before summer — particularly the quickly disintegrating leaves of maple and poplar. The thicker, more rigid leaves of oak and magnolia are slower to break down, so they're better as mulch. They'll still be intact next summer when the soil needs protection from the scorching sun and heavy rains. Don't use walnut leaves as they can produce a toxin as they break down.
Ready to dig your leaves into the vegetable garden? Try this five-step process:
- Mark off where next year's rows will be planted.
- Next to each reserved row, dig a trench and fill it with leaves.
- Cover the leaves with backfill, then top with a protective mulch.
- In spring, plant reserved rows as anticipated, leaving amended soil fallow. Before planting, check your soil pH, as some leaves can change the pH level.
- Next fall, swap rows: Reserve fallow rows for planting and dig leaves into the rows you just harvested.
Steps to Protect Your Garden in Winter
Preparing a garden for winter also means protecting the garden for winter — at least with ornamentals.
- Restock mulch after the ground has frozen to prevent frost heaving or plants being uprooted due to winter's frost-thaw cycle.
- Prune plants when they're dormant. If you need to prune during the growing season, avoid late summer and early fall because plants may put out new growth that isn't winter hardy. Many plants, like hydrangea don't need to be pruned and most shrubs and trees should be pruned in late winter, right before the new growth.
- Wrap the trunks of thin-bark trees like apple trees and other newly planted trees to prevent frost cracking.
- Protect susceptible evergreens such as arborvitae from drying out by wrapping in burlap or spraying with an anti-desiccant.
- Prevent animal browsing with repellent sprays or physical barriers, such as farm fencing, chicken wire or plastic trunk guards left in place for the winter.
Visit Burpee's growing guides for more tips on cultivating successful gardens.