Here in zone 6b we were told that it wasn’t possible to harvest vegetables for ten months each year unless we used some sort of extensive cover. Not having the money to build a greenhouse or hoop house, and having too much wind to manage row covers well, we needed another plan. Carefully selecting varieties of each vegetable, employing straw for insulation, and overwintering baby-sized cool season vegetables, we’ve consistently harvested for ten months each year. Would you like to learn how to do this in your garden?
Selecting the Right Seeds
Whenever possible, choose open pollinated seeds as the resulting plants produce seeds that grow true to type. This way you’ll always have the option of letting a few plants go to seed. Continue to save your own seed and further develop plants that perform especially well in your garden and climate.
A specific type of breeding involves developing stable, open pollinated, plants under very cold growing conditions. These “ice-bred” plants are selected for their ability to perform in the depths of winter. Brett Grohsgal of Even Star Organic Farm in Eastern Shore, Maryland has developed a number of ice-bred greens. We use many of his Fall/Winter Gardening Tips for our winter garden. As Brett says, “The greens will flower and stop making leaves for you sometime in April or May. Don’t expect these to grow through the warm months.” Instead, let them set seed and you’ll have started your own continuing line of ice-bred plants that survive your garden’s coldest months.
When your goal is the longest growing season possible, you’ll probably want a few hybrid cultivars developed especially for the coolest times of the year. Choose your varieties from seed houses that grow their seed in cold climates to reliably get vegetables that perform well in extreme cold. We use two seed growers in Maine because they have a strong focus on hybrids bred for cold locations and on open pollinated ice-bred seed lines. Johnny’s Select Seeds, an employee owned business, and Fedco Seeds, a growers’ cooperative, have excellent reputations for their cold hardy vegetable lines.
Insulate with Straw and Plant for Winter Harvest
Straw makes a wonderful insulator for wintertime plants as we discussed in Part 1 of this series. We begin seeding for winter harvest as early as the beginning of August when we put in our first beds of turnips, winter radishes, and rutabaga. By mid-August we’re transplanting seedlings of broccoli, cauliflower, and cabbages. As these plants grow, we surround them with blankets of straw to protect their roots from the heat of late summer, followed by the cold of early winter. Beets and lettuces are direct-sown in late August, with continued planting of lettuces and mustards through October. Straw surrounds these plants as well once they are several inches tall. When an early frost or freeze threatens, pull a covering of the straw over the plants and most of them will come through undamaged. Turnips can be covered completely by straw once they are full grown and kept in “cold-storage” directly in the garden. Cut off the greens before covering them and top with 6-8 inches of straw. Harvest as needed any time the ground below the straw isn’t frozen. Swiss chard seems oblivious to temperature extremes. It is our go-to green in the summer months, but the new, small growth on existing roots has survived into the low teens in our garden. In late January the 6 inch leaves on our chard stayed a glossy green after three nights at 15 degrees.
Overwintering for Early Harvest
Many plants that can’t survive a hard freeze (below 24 degrees Fahrenheit) when mature, pull through extremely cold temperatures when in the baby stage. This positions them to put on an early growth spurt giving you a harvest 4-6 weeks ahead of early spring seed plantings. We plant cold hardy lettuces, kale, mustards, and spinach in October hoping to get it to just a few inches tall before cooler temperatures inhibit growth. The ones that stay below 6 inches tall pull through single digit nights and are ready for harvest in March. During a particularly hard winter here in the Mid-Atlantic, the greens on these plants appeared to have died. But the straw-covered roots survived and we were harvesting from them by the beginning of April.
Are you ready to harvest abundantly during the winter months? Start selecting the right seeds, insulate with straw, plant late in the year, and plan to overwinter baby greens. Let us know about your successes, and which seed varieties work well for you.