Growing Cold-Hardy Winter Greens

winter greens

It’s so rewarding to put on your toque and boots and run out for a bowl of fresh greens while the ground is still covered in snow!

For farmers relying on selling winter greens for income, there’s more to consider than what I’ll describe. Whole books and conferences are devoted to this subject. But for the backyard gardener, growing some winter greens isn’t as crazy as you might think. Best case scenario: You have homegrown greens in the winter, fresher than anything from the grocery store. Worst case scenario: You’re in the same boat as you were before.

For winter harvesting, there are typically 2 options:

1) Grow cold-hardy crops in the fall and “store” them as full-size living plants, with some type of protection (greenhouse, cold frame, hoophouse, row cover) and harvest throughout the winter.

2) Start plants that are small going into the winter, protect them, then watch them really start growing in February when day length is getting longer (if in a tunnel) or once the snow melts (if outdoors with row cover).

Alternatively, to start harvesting in April, you can sow your seeds in February in a protected spot like a hoophouse. This is what we focus on at our farm for selling cold-hardy crops at the farmers’ market in April and May.

unheated high tunnel

There’s still time this winter to plant if you have a protected area.

What’s a protected area? If you’ve got a hoophouse or cold frame over a garden bed, you’re all set. It doesn’t need to be big. Different sized structures respond differently in very cold or very sunny weather. Trial and error will teach you what works well with your structure. You’ll probably want to use floating row cover to add extra insulation.

winter greenhouse

If you don’t have any structures to protect your crops in the winter, your best bet would be to plant in the fall (like September), and cover with floating row cover (make sure to secure it down well – or it could fly away in high winds!).  Your plants will start to grow once the snow melts.

Cold-hardy crops can also be planted in your regular garden once the snow has melted– you don’t need to wait for the frost-free date to pass, just plant as soon as your soil has thawed enough (row cover is beneficial here too).

What to Plant

Root vegetables are possible, but the easiest crops to start with are greens. Spinach and kale are well-known though some of the most cold-hardy are more unusual.

Claytonia (aka Miner’s Lettuce) has a mild flavour. We usually cut it at least 4 times, letting it grow back between harvests. Even when flowers develop, it’s still good to eat and looks beautiful, so we keep cutting and eating it.

Miner's Lettuce

Mache (aka Corn Salad) is pronounced mosh. This is perhaps the best-tasting green out there. It has a sweet and nutty flavour. We harvest the whole small head and add it to salads.

Corn Salad

This past January, the weather was wild – very cold with strong winds….then warm (at our place it got up to 17 degrees!) with melting snow and rain. I had some fall planted Mache out in the field – no cover whatsoever – which we harvested when the snow melted – it was perfect and delicious. No other winter green can compare to that!

Last year, we planted some Claytonia in our unheated hoophouse in February. We harvested it plenty of times but a few plants set seed which fell on the soil. All summer long, that hoophouse grew tomatoes and once the cold weather came and those tomato plants died, the claytonia seeds that had lain dormant all summer started to grow. Without doing any planting, we had winter greens to eat.

Eating Corn Salad

 Steps to Harvest

Step 1: Buy the seeds. Check out local seed companies.  If you can’t find what you’re looking for locally, try High Mowing Seeds or Johnny’s Selected Seeds.

Step 2: Plant the seeds on a milder day. We usually plant the seeds by mid- September for winter harvest or in February or March for early spring harvests.

winter farmers

Step 3: Take care of your plants. You won’t need to water much in the winter but during a warm spell it’s a good idea to check the soil moisture. Some gardens get too wet when soil melts which is when a raised bed would come in handy. There aren’t many weeds that like to grow in winter conditions but chickweed does. Luckily, chickweed is good-tasting and healthy so weeding can contribute to your salad.

Step 4: Harvest your winter greens. Ideally you’ll want to do this on a milder day, during the warmest part of the day. Don’t harvest crops when they’re frozen or they’ll just get gooey when they thaw out.

Risks with Winter Growing

Freeze and thaws are not ideal for plant survival. Very cold conditions without snow cover can be damaging. Layers of floating row cover can provide the insulating effect that snow would offer. Animals like deer or rodents may want to share in your harvest. Some plant diseases are more common in cooler weather.

Row Cover

Another thing to consider with winter growing is nitrates. Throughout the year, plants trap nitrates and use them for photosynthesis. When light levels are very low (especially in December and January) and less photosynthesis is happening, plants may become too concentrated in nitrates, which can be a health concern for those eating the greens. Nitrates are higher in plants when light, temperature, pH, and moisture are low. The use of chemical fertilizer or uncomposted manure increases the uptake of nitrates. On our farm, we don’t add any extra fertility when planting winter greens (for us, this includes compost and crab meal).

Share your Experience

We’d love to hear about your winter growing adventures and which crops you’ve found the greatest success with!

winter greens

List of some Cold-hardy Vegetables

  • Claytonia
  • Mache
  • Spinach
  • Kale
  • Asian greens: Tatsoi, Pac Choi, Mizuna, Komatsuna
  • Arugula
  • Minutina
  • Cress
  • Cilantro
  • Chard
  • Endive
  • Lettuce (especially at a baby stage)
  • Beet greens
  • Carrots (especially the variety Napoli)
  • Green onions (especially the variety Evergreen Winter Hardy)
  • Radishes
  • Turnips

Shannon wrote this article for a gardening series in the magazine Rural Delivery. If you’re into learning more about gardening, Rural Delivery will have different growers offering tips and tricks each month. Check it out by subscribing or checking it out at your local library or through the national Canadian Organic Growers library.

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