Traditionally, the vegetable growing season runs from the long weekend in May until the first frost in September. Yet, East Coast gardeners stretch the homegrown harvest into late autumn and even winter by pairing cold hardy vegetables with basic season extenders.
By learning to harvest into winter, not only do you enjoy garden-fresh vegetables for longer, but many crops actually taste better in the winter. Vegetables like carrots, parsnips, kale, leeks, and beets become sweeter in cold weather as their starches turn to sugars.
I also love that the winter garden is less work. Once the ground freezes in late autumn, there’s no more watering, weeding, or slugs. Pests like deer or rabbits can’t access the crops because they’re covered with season extending structures or a deep layer of mulch.
These are some of the season extending devices I use in my garden to harvest all winter long:
Row covers: Lightweight, semi-transparent fabrics draped or suspended over vegetables to offer several degrees of frost protection. They allow water, air, and light to reach the plants, and can stretch the harvest for an additional four to six weeks. Find them at your local garden or hardware store in pre-cut lengths as well as by the roll.
Mini hoop tunnels: Quick and easy to build and protect cold-hardy crops for months. A mini hoop tunnel is just a small greenhouse, and I build ours from lengths of four cm-diameter PVC pipe covered with greenhouse plastic. To hold the hoops secure, slip the ends of the hoop over 30 cm-long rebar stakes pounded in the soil. Space the hoops every metre along the bed.
Cold frames: If I could pick just one season extender, this would be it. A cold frame is more permanent than a mini hoop tunnel or row cover, but it allows you to grow more food in colder temperatures. A cold frame is a bottomless box with a clear top. The box provides protection from the elements and the top captures solar energy, creating a microclimate around your plants. A cold frame top can be made from an old window or a piece of polycarbonate.
Mulch: The easiest and cheapest way to extend the harvest is to mulch root crops like carrots, parsnips, and beets with a 30 cm-deep layer of straw or shredded leaves in late autumn. Cover the mulch with an old row cover or bed sheet to hold the insulating materials in place, and then weigh the edges down with rocks. When you want to dig for roots simply lift the cover, push back the mulch, and harvest.
Five crops for your winter garden
You may be surprised how many vegetables you can grow in winter. We harvest several dozen types of vegetables from December to March including kale, spinach, arugula, leeks, scallions, parsnips, carrots, and celery root.
Kale. Kale is a cold season superstar providing a leafy harvest all winter long when sheltered under a mini hoop tunnel or cold frame. Stick to the most cold-tolerant varieties like Winterbor or Red Russian.
Carrots. Winter carrots are like garden candy. As the temperature drops, the starches in the roots convert to sugars, making them incredibly sweet. Sow seed for winter carrots in mid-summer and mulch the bed deeply in late fall to insulate for winter harvesting.
Spinach. Spinach is a great choice for winter cold frames or mini hoop tunnels. The plants are cold tolerant, allowing you to harvest throughout winter and will even re-sprout in March once the days begin to lengthen.
Mache. Also known as corn salad, mache is one of our favourite cold season leafy greens.
The plants form small rosettes that are harvested whole. We like to toss the rosettes with olive oil and fresh lemon juice for a simple, but sublime salad.
Parsnips. A popular root crop in Atlantic Canada, parsnips taste better after a few hard freezes. In fact, our sweetest parsnips come from the winter garden. To winter harvest, deep mulch the roots in late autumn with shredded leaves or straw. Dig all winter as needed.