Gardeners living in mild and cold climates can take advantage of long winter months with a kind of gardening called overwintering. It involves leaving produce in the ground during the winter, to harvest the following spring and summer. These plants tend to be hardy, waiting for the lengthening days of spring to finish growing. Overwintering provides harvest from early spring to summer, around the time most spring crops are first being sowed.
There are many advantages with overwintering. First, overwintering makes use of your garden space through the down time of the year. These crops can replace others that are harvested during the summer, so that your garden is made useful all year long. Second, overwintering crops grow when pest pressure is low or absent altogether, with minimal protection required.
Crops that benefit from overwintering:
Broccoli: Unlike main season broccoli, overwintering broccoli produces a small, nickel-sized broccoli on long shoots. Start seeds indoors under bright lights before the end of June to transplant into the garden 10-12 weeks before the first frost. It may be picked in February (very early), March (early) or April through June (late).
Cabbage: Sow varieties indoors in July, to transplant in August. Cabbages improve flavour during cold weather.
Cauliflower: A classic overwintering heirloom that is perfect and ready to harvest in April and May. Sow types indoors under bright lights around mid-July, then transplant mid-August.
Garlic: Plant from September to October, before the first hard frost. Overwintering garlic may be harvested in early July as the largest bulbs. If carefully dried and cured, overwintering garlic could last to the following March.
Onions: Sow seeds indoors in trays in late June to early July, then transplant by the middle of August, to harvest the following June. Walla Walla is a classic onion variety that is ideal for planting in late summer and overwintering in the ground. It requires a lot of time to grow to reach its maximized size and sweet taste.
Tips for overwintering
- Plant crops on time – depending on the crop, overwintered varieties are planted between mid-summer and early fall. Tip: garlic is a hardy crop that can be planted anytime during fall and even later into the winter for next year’s summer crop
- Keep crops protected from the cold – utilize floating row covers to protect plants from extreme temperatures and drying winds
- Beware of pests – slugs, wireworms and vermin are popular during the winter season so keep an eye on your crops for damage and harvest crops when necessary
Overwintering crops in the garden can be both incredibly satisfying and challenging. Overwintering cannot guarantee bountiful harvests, but it is worth the minimal investment of time and resources. Harvesting your own fresh salad or cooking greens can bolster your spirit on a cold, dark winter day.