We've already written about using a cold frame to lengthen the growth season. Given the length of the New England growing season, a season extender will let you to maintain a slightly warmer soil and air temperature surrounding your plants, enabling you to continue growing through November and begin planting earlier in the spring — in March or even late February!
However, did you know that you can continue to grow even in the winter? Your garden won't produce much in December, January, or February, but these are the best months to overwinter crops for a harvest in the early spring. Cool-weather crops are best planted in the early to mid-fall, allowed to develop a root system in October and November, then allowed to dormancy during the chilly and dark winter months before emerging in the spring. You may harvest before your neighbors are even starting to sow their first crops by establishing cold frames and overwintering crops!
Slower and distinct
Along with more obscure hardy winter greens like claytonia, mache, and sorrel, you can overwinter crops like beets, carrots, kale, spinach, and scallions. A sweet salad green called Claytonia, also referred to as "miner's lettuce," is one of the first overwintering crops to appear in the spring. Even with minimal water and in the cold, it can survive.
Taking care of a winter garden is different than taking care of a summer garden. Weed and insect pressures are either nonexistent or much diminished as a result of the low temperature and sunshine levels. Less evaporation of water is also a result of these same factors. You won't need to water frequently because the moisture in the ground will stay there.
However, these circumstances might also result in mold or mildew problems. Keep an eye out for fungal symptoms.
Depending on planting time and plant type, the vegetables in an overwintering garden (let's say from October through March) will mature at various stages and at various dates. Consider cabbages, leeks, and root vegetables as being in a "root cellar," such as carrots, storage radishes, rutabagas, turnips, etc.
They have finished growing and have been holding for months while they wait to be harvested.
Pick lettuce, cutting greens, kale, salad radishes, and scallions as soon as they are large enough to be harvested. However, they can also continue to develop (although slowly as a result of the waning sunshine) and be harvested over time.
When cold weather strikes, if the same crops have just been planted or moved and are still immature, they will sustain themselves and start to grow again after the new year. They will supply you with these crops for your late-winter harvests.
You should be aware that it's ideal to harvest any winter-started crops by the end of February for two reasons:
The longer days and warmer temperatures of the next spring will encourage many crops, including spinach and lettuce as well as carrots and leeks, to go to seed or bolt. The plants will soon lose their ability to be eaten, even if they bravely endured the winter in outstanding health. Harvest them before they turn before they do.
It's time to prepare the land they were using for the following crops—the lettuce, radishes, and scallions that would be sown in late winter or early spring.
The wintertime climate varies from year to year. You may or may not need to protect your crops.
It might not even be necessary at all during mild years. Other times, exceptionally cold weather could require you to offer cover. Not to worry. Simple protection will suffice.
With root crops, it may only entail a small amount of extra dirt being dragged over their shoulders (depending on how long they are to stay in the ground). Alternately, you might arrange straw bales in a straight line on either side of your leek row, with a few free pieces on top for cover. For further details on arrangements that provide protection from the cold, see "Hot Beds & Cold Frames," below.
Additionally, depending on the species, different plants may withstand cold temperatures to varying degrees. For instance, cabbage and Brussels sprouts can safely stand out in the first snowfall. However, lettuce and salad radishes will always benefit from some protection.
It's also true that your crops can survive colder temperatures the healthier they are and the more carbohydrates and sugars they create during their growth. Plant antifreeze: sugars So make sure the soil is fertile to help them survive.
Also keep in mind that some crops, including spinach, leeks, and scallions, can be harvested frozen. They retain their quality and are still quite useful after thawing. Mâche, kale, and other lettuce varieties can also freeze through and thaw out in the open, appearing to be adequately unharmed and able to continue growing.
Numerous crops with a knack for surviving cold temperatures have already been mentioned. So let's examine some of the top contenders for the overwintering garden in more detail.
Christmastime favourite: Brussels sprouts
Don't overlook the cold's sweetening influence on Brussels sprouts. Before at least a couple of frosts, do not harvest any sprouts. If you want sprouts into January, you might prefer to "see red" even though Igor is a green type that can endure stronger freezes.
The several red sprout types With relatively minimal protection, Rubine and Redarling, in particular, can keep sprout quality for months. It takes brussels sprouts a long time to mature. So that they will be fully mature as winter approaches, start them early (in late spring or early summer).
Try the distinctive, cold-tolerant, and trademarked Kalettes for a slightly different harvest. Where their sprouts should be, they produce tiny florets instead!
Cabbage: Generous and Trustworthy
Savoys are the best cabbages for overwintering because of their crinkly, tasty, and nutritious leaves, but green and red varieties also do well (but require protection).
Choose between January King, Deadon, or Winterfurst for a savoy. Good ecological options are Dottenfelder Storage, European Storage, and Storage No. 4. The preferred reds are Mammoth Red Rock and Ruby Perfection.
Chinese Cabbage: A Unique Slight Variation
A delightful and unexpected addition to a winter dinner is Chinese cabbage.
All types are not made equal and are not truly built for cold climates. Try Suzuko first, though. Heads are still viable through December with protection.
"Carrots": Finding Gold
For a longer crop, sow carrots in succession from late July to mid-August. They should ideally be grown within a building (cold frame or greenhouse) that is covered in straw or a row cover.
This is more to facilitate harvesting than it is to properly protect the crop. You'll understand the wisdom after you attempt to dig a carrot out of freezing ground. Pick amongst the Snow Man (white-fleshed), Yellowstone (yellow), Naval, Napoli, and Merida variants (orange).
Love Those Leaves, Kale, Lettuce, Spinach!
Whether they were planted for late autumn/early winter harvesting or planted after the turn of the year for late winter and early spring, a wide variety of plants' leaves are well suited to winter output.
Give these kinds a spot if you prefer chicory, endive, escarole, radicchio, or arugula.
Mâche and claytonia are two other greens that are very important for winter gardeners and that you won't want to overlook. Although they don't survive the coldest weather, these winter annuals nonetheless grow incredibly well.
The three most common greens—kale, lettuce, and spinach—require particular variety selection and multiple layers of protection. The sensitive and mild Siberian varieties are possibly the hardesty for frost-sweetened kale. Due to its size, Improved Dwarf Siberian works very well.
But among the numerous kale kinds, there are a lot of unique variants. These include the wavy Winterbor and Vates, as well as the ruffled-flat Beedy's Camden and Judy's Kale (all of which are extremely tough).
Leaf lettuces do best when planted densely and harvested while they are young. (Favorite songs include Tango and Red Tinged Winter.) However, further choices for fans of headed lettuce include:
- Romaines: Winter Density, Winter Wonderland and (red) Rouge d’Hiver
- Butterheads: Winter Marvel and North Pole
- Jack Ice (crisphead)
Surprise! Pea Shoots
Salad Turnips & Radishes: A Roots Riot
Try Chinese Red Meat, Starburst, or Beauty Heart; they're all quite lovely!
You could make use of the following to protect crops.
- Old blankets or bed sheets to cover, held up with stakes. Old windows to cover, letting in light to heat the space on bright days and held up with bales. Straw or (chopped) leaf mulch to cover, with or without bales as sides (i.e., a simply constructed cold frame)
- Low tunnel made of hoops and plastic sheeting that has a row cover and may or may not have frost blankets
- Low tunnel, cold frame, or hot bed inside a greenhouse. Cold frame made of wood. Unheated greenhouse. Hot bed. A growth frame warmed by heat generated from decaying organic matter, such as animal bedding/manure, leaves, and forest debris. Wool, seaweed, and cotton clothes.
- Note: It is important to keep an eye out for overheating in any system that produces heat from sunlight or decomposition as well as to ensure that the temperature is kept at a comfortable level.