PHOTO: Susy Morris/Flickr
January 18, 2016

As the summer growing season wanes, gardeners are left to wonder how they might continue the joy of harvesting fresh food. There’s no reason to think that winter yields are impossible—in fact, with careful planning and a bit of luck from the weather, growers can eat from their garden every month of the year. Here are some tips to extend the growing season and continue eating locally.

1. Leave Crops In The Ground

Many root vegetables, like carrots, parsnips and beets, improve with exposure to chilly temperatures, so you can leave them in the ground until you’re ready to harvest, even through light snows. For the best texture, harvest the produce before a deep freeze.

When temperatures are cold, you’ll want to wait until midday to harvest, so the ground is at its warmest. Digging in frozen soil can create compaction and disturb soil tilth. Waiting until the warmth of the afternoon means you’ll cause less damage to the soil and enjoy your garden work more.

2. Grow Inside

Bring potted herbs inside, so you can harvest them in the cold season.
Bring potted herbs inside, so you can harvest them in the cold season. Photo by Kristine Paulus/Flickr.

Tender perennials, like rosemary and lavender, thrive if potted and moved indoors for the winter. They can tolerate some cold, so keep them on an unheated porch if you like. Water the soil sparingly, and mist the leaves. You can transplant tender perennials back outside in the spring or just move the containers back to your porch or deck.

3. Deep Mulch

Deep mulching with straw will prevent your plants' roots from freezing.
Deep mulching with straw will prevent your plants’ roots from freezing. Photo by Doug Beckers/Flickr.

Lightweight mulches, like straw, offer plant leaves and roots protection from cold and wind. Deep mulching—applying several layers of mulch material—is effective for cold-hardy, dense vegetables, like cabbages, turnips, beets and kohlrabi, and small-leaved perennial herbs, like thyme and oregano. Mark the ends of rows and cover them with 6 to 12 inches of straw. When you want to harvest, dig through the straw, pluck a vegetable, and replace the mulch. This technique allows zone 6 farmers in my area of Ohio to harvest cabbages in February.

4. Use Row Covers

Floating row covers can raise the air and soil temperature around your garden, thus extending the growing season.
Floating row covers can raise the air and soil temperature around your garden, thus extending the growing season. Photo by Susy Morris/Flickr

Row covers—layers of fabric or plastic over small metal or plastic hoops—increase the air and soil temperature around your garden by trapping solar heat. The warm bubble under cover allows kale, chard and cold-tolerant lettuces to continue growing while protecting roots from freezing.

Design your row cover system to be easily removable, so you can open up the air space when needed to ventilate heat or collect food. Choose materials that are rated to provide the temperature protection you need. Lightweight fabric is great for protecting greens from an early frost. My farm, Swainway Urban Farm in Columbus Ohio, uses a layer of perforated plastic covered by midweight fabric to protect our fall carrot crop for harvests well past Christmas.

Because the heatable air space is fairly small, rows can get too warm too quickly and burn tender leaves of lettuce and similar crops. Keep an eye on the outdoor temperature and figure that on a sunny day, rows under clear cover will be as much as 40 degrees F higher than the surrounding area.

5. Build A Root Cellar

Store your harvest in a root cellar or cold-room storage area to make your root vegetables, squash and other produce last through the cold season.
Store your harvest in a root cellar or cold-room storage area to make your root vegetables, squash and other produce last through the cold season. Photo by iStock/Thinkstock

Many fruits and vegetables can be stored for months under the right conditions—the ultimate way to extend your harvest. Traditional farm houses often included a root cellar or a small outbuilding for this purpose, but modern homes often have spaces that can mimic the same conditions. Build an outdoor root cellar by digging into the side of a hill or directly in the ground. Excavate a space and top it with an old door or sheet of wood to keep out precipitation and wind. You could also build a cold-storage area in your basement or spare room, if you don’t have enough land for an outdoor storage area.

Crops like squash, potatoes, carrots and apples all need similar circumstances to store: cool temperature (33 to 40 degrees F), high humidity (80 to 95 percent), darkness and ventilation. A basement room with an earthen floor is ideal. Barring that, pack vegetables in slightly dampened sawdust or paper in a wooden crate and store in the coolest, darkest spot you have.

Store vegetables in crates or baskets to allow aeration and have a plan for heavy rains—if a dug cellar fills with water, your produce may be ruined. Often vegetables keep best when left unwashed, though winter squash benefits from being wiped with a rag soaked in white vinegar to kill fungus or mold spores that frequently linger on the surface.

Whatever root cellar option you build, be sure to check on your food often. Remove any rotting pieces to prevent the spread of molds and fungus.

6. Use Grow Lights

Try growing plants, like microgreens and herbs, under grow lights to harvest in the winter.
Try growing plants, like microgreens and herbs, under grow lights to harvest in the winter. Photo by Josh Kelahan/Flickr

If you have a see- starting setup and some extra seeds, consider growing microgreens or lettuces during the winter. Kale, broccoli and radish can all be grown as microgreens when seeded densely on a thin layer of soil. Sow lettuces in deeper trays for cut and come again convenience. Many young greens can be cut after as few as two weeks, so you can easily supplement your family’s salads for the months between late fall and when you begin starting seeds in the spring.

Plan For Next Year

If your crops are already dug up or you don’t have the option of investing in root cellaring, row covers or lights right now, stay warm by planning for next year. Include space for an extended fall harvest in your garden sketches. Add cold-hardy seeds to your wish list. Plan successions of roots and greens, start amassing mulching materials or save up for a hoop house to increase your winter growing potential. The cooler seasons don’t have to leave gardeners wringing their hands indoors. Experiment with winter growing and you’ll be surprised at the abundance that’s possible.



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