Few things are more satisfying than harvesting fresh, home-grown vegetables in the heart of a cold and snowy winter. Growing throughout the winter takes foresight, as well as some dedication and flexibility. It all starts with the early preparation of the seeds and seedlings to ensure they have the proper warm environment to flourish before the cold weather begins.
Choosing the right varieties for the greenhouse, crops that can withstand the potential hardships that come with winter is an important consideration for growers without supplemental aid. Because temperatures in the greenhouse may fluctuate dramatically in the winter, and the light quality isn’t as ideal, a lack proper management can become detrimental to more fragile plants.
Greater patience may also be necessary. In the summer, for example, an English cucumber only takes about ten days to mature from flower to cake. Whereas in the winter, it can take three weeks or longer, even at ideal temps from 65-75 degrees Fahrenheit during the daytime. However, as stated in a previous blog entry, there are many cold-weather crops that are more forgiving, as well as methods for creating an ideal growing space without a great deal of effort or cost.
Below we’ve provided a table of basic timing guidelines for planting and harvesting. These are some excellent cold-weather crops, which can be done in the greenhouse or in cold frames. These date ranges are based on growing in zone 5 without any auxiliary heat/light sources. Depending on your own greenhouse setup, there’s a good chance you can expand the timing and the crop types, especially when using some of the techniques we explored in our earlier winter greenhouse blog.
|Arugula||Throughout August||Early October to Spring|
|Endive||Mid to late July||Mid-september to Early December|
|Lettuce||Late July to early September||Mid-September to early December|
|Mizuna||Early to mid-August||Mid-September to early December|
|Parsley||Early June to mid-July||Early October to Spring|
|Radish||Early September to mid-October||Early October to early December|
|Scallion||Early to mid-July||Early October to Spring|
|Spinach||Early September to mid-October||Mid-October to Spring|
|Swiss Chard||Early July to early August||Early October to Spring|
|Carrot||Early August||Early Dec to Spring|
|Kohlrabi||Early to mid August||Early November to Spring|
|Radicchio||Early June to early August||Early December to Spring|
|Sorrel||Early to late August||Early November to Spring|
|Spinach||Early August to mid October||Early November to Spring|
For further reading on winter growing and harvest, both in and out of the greenhouse, check out Eliot Coleman’s books, ‘Four-Season Harvest,’ and ‘The Winter Harvest Handbook.’
We’re closing this entry with a wonderful winter warmer recipe: a simple and delicious Roasted Carrot Soup. Enjoy!
- 6 to 8 large carrots (about 1 3/4 pounds)
- 1/4 cup olive oil
- Salt to taste
- 6 cups low-sodium vegetable stock
- 1-inch-long piece of peeled ginger
- 1 sprig thyme, plus more for garnish
- 1/2 large sweet onion, chopped
- 2-4 large garlic cloves, chopped
- Freshly ground black pepper to taste
- Start by peeling and chopping the carrots into 1/2-inch rounds slices. Place prepared carrots in a rimmed baking sheet, toss with 2 tablespoons of the olive oil and sprinkle generously with salt. Set your oven rack about 6 to 8 inches from the heat source and turn on the broiler and broil the carrots until they brown and soften, turning them over with a spatula every 5 minutes or so. It should take about 15 to 20 minutes.
- While broiling the carrots, bring the stock to a boil in a medium-large stockpot, and add the ginger and sprig of thyme. Simmer the stock gently for 15 minutes.
- Put the chopped onion in a large sauté pan with the remaining olive oil and brown them over medium heat, stirring frequently. Once browned, add the garlic and the softened carrots and sauté for another 5 minutes.
- Remove the ginger and thyme from the stock, then add the onions, garlic and carrots to the broth. Bring to boil then simmer for 5 to 10 minutes, until the carrots are soft enough to puree.
- Use an immersion blender, standard blender or food processor to puree the mixture until smooth. If the soup seems too thick, you may add more stock or water and reheat gently. Add salt and pepper to taste, then serve garnished with fresh chopped thyme. Serves 4 – 6.