As summer winds down in the Northern Hemisphere, most gardening tasks involve extending the growing season or preparing to tuck the garden in for the winter. However, you don’t have to put your garden to sleep for the cold months. With a little knowledge, the right plants and tools, and a spirit of experimentation, you can harvest fresh vegetables and greens from your winter garden during the coldest months of the year. Here are some winter gardening tips and tricks to get you started on year-round garden harvests.
Protect Your Plants from the Cold
Temperature — both air and soil — is one of the most important factors in whether your plants survive and how well they thrive in a cold weather garden. Prepping for winter growing includes getting the right tools and technology to help monitor and protect your plants. Here's a breakdown of important tasks and tools to help you plan and maintain your winter plants:
- Clean away debris. After the growing season is over, pull up tomatoes, pumpkins, squash, and other fruiting plants and either compost or dispose of them.
- Monitor temperatures for indicators of overnight frosts. Check out Growing a Thriving Vegetable Garden in Cold Climates to learn how Kathy Purdy, owner of Cold Climate Gardening, uses AcuRite Access™ and a personal weather station to monitor conditions in her garden and predict the occurrence of frost. As she notes, the conditions in your garden can vary significantly from the environment just a few blocks or houses away. A personal weather station uses the most accurate data for your garden and alerts you when temperatures hit dangerous levels for your plants.
- Cover tender plants at night. Covering vulnerable plants helps retain heat, preventing frost damage. You can use hoop houses, row covers, or individual cold frames to cover and protect your plants. Check out the chart at almanac.com to learn which plants are most vulnerable to low temperatures.
- Leafy greens, such as spinach, kale, and collard greens, can withstand light frosts, especially if you cover them at night and help preserve ground heat during the day. Check out this tutorial on how to build a hoop house for your greens.
Tricks for Extending the Gardening Season
If you don’t have room for a greenhouse, building cold frames is a great way to extend your gardening season as they will help your plants retain heat and stay protected from frost. Root vegetables can stay in the ground until it freezes. With a combination of cold frames and passive heating tricks, you may be able to harvest carrots, rutabagas, potatoes, and other tubers throughout the winter.
Here’s how to make the most of your cold frames:
- Build your cold frame properly to take advantage of your garden's conditions. The back side — typically facing north — should be higher than the front. That allows water to run off and provides maximum sun exposure.
- Use a crock pot or birdbath heater in a ceramic pot to heat a cold frame during cold winter nights. Note: If you are going to use a heater in your cold fame, be sure to monitor the temperature to ensure that things don’t get too hot!
- Consider building a hot bed using a soil warmer cable.
When to Plant for Winter Harvests
The trick to having plants to harvest throughout the winter is early planting. Most reference sources will tell you that you should have started planting your winter garden in June or July, but it's not too late to start even in September. You just want to get them in the ground or a raised bed with enough time to get established before the first frost.
Depending on your USDA zone — you can learn more about that here — you can plant as late as mid-October, as long as you choose plants that love cool temperatures. Remember that plants will grow more slowly or stop growing altogether during the darkest days of winter, but if they're already established, you'll be able to harvest them as you keep them alive.
10 Plants That Thrive in a Winter Garden
Kale and collard greens are standards for fall and winter gardens, but they're not your only choices. Here are 10 popular veggies for winter garden growing:
- Carrots are especially sweet and tender after experiencing a couple of frosts. Plant them in midsummer to enjoy them through the winter.
- Spinach will grow happily through cool weather and survive through the winter in a cold frame. Harvest leaves as needed, and sow directly in the soil in the cold frame.
- Mesclun salad mix is a good candidate for cold-frame gardening. Like with spinach, you can sow seed for successive harvests throughout the winter.
- Broccoli loves cool weather. Start it in late summer or early fall for a late fall harvest. Grow it in a cold frame and you can continue to harvest it through the winter. Ditto for cauliflower and Brussels sprouts.
- Swiss chard is remarkably cold tolerant. Plant a rainbow variety in a sunny spot to enjoy its bright colors and tangy taste all winter long.
- Arugula will do nicely through the winter if you grow it under cover. Look for Ice-bred, Tuscan or Astro for excellent winter eating.
- Mustard greens are a largely overlooked plant, but they're powerhouses of nutrition and flavor. Their seeds will germinate in soil temperatures as low as 40 °F (4.44 °C), making them an ideal candidate for winter gardens.
- Radishes are popular winter garden plants, especially the winter varieties, which are more colorful and flavorful.
- Curly parsley is a cold lover. It grows slowly, but provides bright green, leafy ground cover in or out of cold frames.
- Mediterranean herbs like sage, rosemary, and thyme will all do well over winter in your garden if you provide them with a little protection from the cold. Dig up a healthy clump of each and plant in a large container, then keep it sheltered to harvest fresh herbs all winter long.
One of the most important things to remember about winter gardening is that you have to pay attention. The temperature inside a cold frame, hoop house, or greenhouse can get dangerously hot for your plants on sunny days, and the cold, dry air means you may have to water once in a while. As Melissa Will notes at Empress of Dirt, you can't just take the winter off if you're growing winter veggies. You need to be prepared to adjust growing conditions on the fly. That's where AcuRite sensors and AcuRite Access™ come in handy. You can set alerts to let you know when the temperature or moisture is outside the safe zone, allowing you to make the necessary modifications.
You don't have to give up your fresh greens and veggies when the days get shorter and the nights get cold. A little planning and careful monitoring can keep you stocked with fresh greens and sweet vegetables until spring rolls around again.