Zone 3 is a challenging gardening environment. The season is short. In a good year you may get a frost-free window between June 1st and August 15th but in a bad year there may be danger of frost throughout the growing season. You can’t count on a 90 day season, and in most years you will be lucky to have a 60 day growing season.
What defines a zone 3 growing season?
Generally agricultural scientists define zone 3 as winter temperatures as low as -40C/F – which we experience one year out of every 5. The zones do not, however, incorporate summer heat units into the hardiness calculation. The zones also don’t take into account the presence of reliable snow cover. According to the hardiness zone maps, my area is a zone 5 – based on plants like Oregon grape, and trees like Western Red Cedar, which survive the winter because of our abundant snow pack. However, with summer frost the norm and our shorter frost free season, we plan our garden for zone 3 hardiness – similar to the Canadian prairies. Perennials that thrive in Manitoba and Saskatchewan will do all right in my zone 3 mountain climate.
Why bother gardening in zone 3?
There’s lots of good reasons to garden in zone 3. Fresh organic produce and herbs can be grown successfully in zone 3 from the beginning of May through to the middle of October with the right varieties, and some protection from frost.
Gardening tips for zone 3 success
In zone 3, nights are cooler, even when summer heat comes at noon. Many crops that grow well in zone 5 to 8, won’t set fruit in zone 3. The ground doesn’t heat up enough to give the heat units necessary to sweeten melons, mature winter squash, sweeten corn, or heat up peppers. Instead supplemental heat must be added to the planting area for success with these heat lovers in zone 3. Choose varieties that set fruit and mature early so that you aren’t waiting all summer for fruit set, only to be disappointed by an early frost.
Plan to use a row cover or greenhouse plastic to protect plants against frost at night. Place large rocks, painted black, in the garden near tender plants. These will heat up during the day, and then give back their heat during the night as temperatures drop. Grow tender plants inside a greenhouse where they are protected a little longer from cold night temperatures.
Rather than buying seeds from a seed rack order from a seed catalogue that specializes in shorter season vegetables. Lindenburg seeds in Manitoba has several vegetable varieties that grow well in our zone.
20 vegetables you can grow in zone 3
In zone 3 successive sowings of lettuce, orach, and spinach will provide salads from June 1st to frost. It rarely gets so hot that the leaves turn bitter. Choose varieties for quick, fast growth and frost resilience. Butterhead, loose-leaf, and early romaine are you best choices for early lettuce that will make fast growth in zone 3’s cooler season. Orach or mountain spinach is also a good choice with its salty magenta leaves and vigorous growth.
In zone 3 radishes can be planted as soon as the snow recedes and can be replanted every 15 days for salads, until July. After July the plants tend to bolt before they bulb and root maggots will damage the roots, as the season progresses. Technically starting winter radishes at the end of June for a fall crop should work well in zone 3, but my experience has been less than stellar. Planting marigolds near radishes should discourage root maggots. Winter radishes grow larger, with a harder flesh like turnips. They can be eaten raw and are pretty on a vegetable tray, but are milder when cooked, similar to rutabagas, another brassica.
Chinese Greens are the backbone of my zone 3 gardening plan. They grow well in cool spring weather and many varieties are bolt resistant in warmer weather. Harvest them by taking the outer leaves and allowing the heart to continue to grow. If you harvest them by cutting all growth but leaving the bottom inch, they may regrow from the root, for a second smaller harvest. Since many are brassicas, and subject to the same pests that radishes, turnips, and cabbage are subject to, you’ll want to establish them into a garden rotation plan as brassicas. Ideally plan for a 4 year rotation – only planting brassicas in the same spot once every 4 years, to discourage soil pests.
The Chinese labourers, that worked the gold mines near Barkerville in the early 1900s, coped with frost year-round but grew productive gardens on the terraced hillsides with bok choy, suey choy, beauty heart radishes, and shungiku (edible chrysanthemum). Most oriental vegetables grow well in the short season of zone 3.
One caution, don’t begin them too early or they will bolt before the leaves develop. I like to plant them in mid May as the soil begins to warm, but before the last frost. Provide a cloche to keep white flies and flea beetles off them in the early part of the season. My favorite resource for learning more about growing and cooking with Chinese greens is this one. (Oriental Vegetables is out of print but used copies are available. It’s worth hunting down if you are a zone 3 gardener.)
Kale and Collards
Kale and collards, while taking more time to mature than Chinese greens, provide substantial harvests of leaves from mid-July to snowfall. If kept under a cloche, they can continue to be harvested until the snow gets too deep to find the bed. If protected from the harshest winter temperatures, they will grow again in early spring, providing tiny broccoli-like florets for salads. Kale is one plant that I’ve successfully saved seed from in my shorter growing season. Most biennials don’t make it through our harsh winters.
From the same family as beets, Swiss chard will provide a continuous harvests of dark leafy greens throughout the growing season. Chard comes in a variety of stem colours and robustness. Wondering about perpetual spinach – it’s a chard with a green stem. It grows the same as other chards.
While winter squash takes a long growing season and needs some heat units to produce viable female blossoms in zone 3, Zucchini and other summer squash will produce a crop in zone 3 if you give it protection from late frost and cover the ground with a black mulch to retain the heat at night. For best results start your plants indoors about May 1st, and plant out after the soil warms up, in June. Provide frost protection in a raised bed and use rocks or jugs of water painted black to act as a heat sink around the plants. If you have a cold spring, you may need to hand pollinate the female blossoms to ensure a good fruit set.
When growing cucumbers or squash in zone 3, not only do you need to protect your plants from frost, but on colder days, when temperatures hover in the 40s or 50s F., pollen may not be viable and bees may be scarce. Picking a cucumber variety that is quick to set fruit with many female blossoms is your best bet for successful harvests. Look for a short season parthenocarpic variety that doesn’t require pollination. Roxynante is an F1 hybrid parthenocarpic variety that matures fruit in 45 days from transplanting, available at West Coast Seeds.
Pickling cucumbers produce small size fruits and continue to produce throughout the season as long as they are kept picked. Look for varieties that mature within 50 days of transplanting, and are genoecious – having mostly female flowers.
Summer celery matures in 45 to 55 days and is faster growing than other celeries. Harvest individual stems and leaves during the growing season, leaving the centre intact to continue to grow.
While peas generally require a longer growing season, they make strong growth in early spring and are usually done in 60 to 65 days. Plant them directly in prepared ground by mid to late April, as soon as the snow is gone. The harvest will be done by early July, allowing you to remove the vines and replant the ground to a fast growing, frost hardy green like Miner’s Lettuce or ruby red Orach, that matures in 50 days. This allows you to get two harvests from the same spot in the garden. Peas increase the available nitrogen in the soil and help the subsequent planting make strong early growth. Keep peas well mulched and weeded so that competition doesn’t slow down their vigorous growth.
Garlic is a long season vegetable that is winter hardy. Plant garlic in October before the first snowfall. It will grow a strong root system during the winter, under the snow, and come out strong in the spring, as soon as the snow is melted. Keep it well weeded and mulch through the growing season and it will be ready to harvest in the first week of August. Replant the same ground with Miner’s lettuce or mescalun mix for a second harvest before frost.
Potatoes are easy to grow if you have a summer without frost. But in a bad year you’ll only get a harvest if the vines flower before they are killed by frost. Plant them about the same time you plant peas, at the end of April. And hill them up with soil as the vines emerge. Mulch them well to keep the soil evenly moist. In the early growing season, even if they get a frost they’ll outgrow it. Once they have flowered they need a few weeks of sunny, warm weather to produce a good harvest. But a frost later in August won’t harm the harvest.
Beans are always iffy for me. The soil is cold and the plants just seem to set the first mature beans – enough for one or two dinners — before the vines are killed by frost. If you have warmer soil you may be successful with beans. I’m just a bit too cold at night for success. Bush beans require a shorter growing season than pole beans by almost 20 days. Cover with a cloche to hold in the daytime heat a little longer for better fruit set.
Beets are a reliable crop in zone 3. Plant after the soil has warmed up at the beginning of June. If you plant too soon the roots don’t swell. Plant at least two varieties for the best harvests over the longest season.
Carrots are best planted using a seed tape. They need to grow fast in zone 3 and without adequate spacing their growth is slowed early in the season. Choose varieties that need only 55 to 70 days to maturity and plant in mid May in zone 3. With cooler nights these will need longer to mature in zone 3. Expect to harvest them in September.
Onions will grow well in zone 3 provided that you start with transplants from the garden centre or grow your own transplants. Onion sets tend to bolt in zone 3’s cooler nights. Onions that send their energy into a seed stock won’t bulb properly. You need a good size green stock by May 1st, when you transplant them into your prepared garden. Cover with a row cover to protect from frost. Keep them well weeded and mulched. For a more detailed explanation of how to successfully grow onions see my post on Homestead Chronicles.
Chives and multiplier onions
Chives and multiplier onions are prolific in zone 3s cooler temperatures. They continue to grow until July’s heat bring on their flowers, offering lots of green stalks for salads, soups, and stir fries.
Rhubarb is hardy in zone 3 and will produce from early spring until the hottest July weather before dying back for the season. Feed them with well composted manure in the early part of the growing season and keep them mulched and well watered for the best tasting stalks.
Asparagus is worth the effort to establish a strong patch. Plant the 3 year old male crowns in a well prepared bed. In the 2rd year from planting you’ll see your first harvest of pencil size asparagus stalks. By the 3rd and 4th year you’ll harvest enough for preserving and sharing. A well-tended asparagus bed will feed you for more than 20 years.
Horseradish is easy to grow in zone 3. Plant roots in the fall or spring. Amend the soil with a shovelful of well composted manure at planting time. Keep well mulched and water in the hottest part of the season. Harvest the roots when the tops die back in the fall. Harvest the roots for fire cider, or preserve the grated root in vinegar for a winter condiment.
This is not an exhaustive list of vegetables that can be grown in zone 3. As you can see there is a large variety of the most common vegetables. Other plants like short season broccoli, cauliflower, and cabbage can be grown with some extra care to ensure that the varieties all mature within 60 days or receive frost protection later in the season. Tomatoes, peppers, and eggplants can be grown in containers or in a greenhouse provided attention is paid to the pollination requirements of each plant.
On the other hand, corn, melons, and winter squash require a lot of space and heroics to get a good harvest in zone 3, with the shortened season and cooler nights.
The key to growing a successful garden in zone 3 is to choose varieties that mature within the 50 to 70 day growing window as well as plants that don’t require a large number of heat units to mature.
More help with your zone 3 garden
Grab the The Gardening Notebook to get your garden planning off to the best start possible. The Gardening Notebook is a printable resource with 127 pages that helps you plan your individual garden, record frost dates, inventory your seed stash, and plan each vegetable or fruit variety in rotation. There’s a place to record your harvests so that you can tweak your garden plan every year based on actual results from your own plantings.
Did one carrot variety do exceptionally well in your location – this is where you’ll keep a record so that you can be sure to plant that one variety again. Did you plant a purple cauliflower that didn’t make it through the first light frost? You’ll be able to check your record so that you skip that variety next time. Seed is expensive, and time can’t be refunded, so keep The Gardening Notebook and you won’t make the same mistake twice. Can’t remember where you planted radishes – a brassica – last year? You’ll be able to know for sure when you check your Gardening Notebook. This is one resource that will save you time and money and focus your efforts for gardening success, even in zone 3. You can’t afford to be without it. Buy your copy today.
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