When to Start Seeds in Zone 2

Zone 2 is the second most extreme climate zone on the USDA Hardiness Zone Map. The map splits the US into 13 zones, each divided by 10°F increments based on the average lowest annual temperature. Each zone is further split into 5°F half zones labeled ‘a’ and ‘b.’

If you live and garden in zone 2, you’re dealing with average winter lows between -40°F (-40°C) and -50°F (-46°C). These sub-arctic regions experience arctic air masses that bring severe wind chill, frost, and snow for most of the year. As brutal as this climate may seem, plants still thrive here. 

As a gardener in these extreme areas, you’ll have a short growing window to work with. Cold-hardy annuals and native perennials will be your best friends. Because of the remoteness of these regions, you’ll probably have to do it all from seed and time them right. 

Where is Zone 2?

Zone 2 regions exist in the highest mountain tops of the Rocky Mountains, Alaska, and Northern Canada. The Alaskan coast of the Arctic Ocean also lies in this frigid area. These remote ports experience extreme lows averaging between -40°F and -45°F (-40°C and -43°C), giving them the designation of 2b.

As you travel further from the moderating influence of the sea, you reach Alaska’s interior. Here, the designation is 2a, meaning winter lows can dip to -50°F (-46°C). Sections of Canada’s Northwest Territories, Yukon, Nunavut, and the Southern coastline of Hudson Bay also fall within zone 2. 

What Is the Climate in Zone 2?

Zone 2 regions have a mixture of sub-Arctic and Arctic tundra and sub-Arctic maritime climates. The big difference is their proximity to the sea. Although both are extremely cold, the difference in average summer temperatures and rainfall has a lot of influence on what you can grow. 

Tundras have low-lying native perennials, grasses, and some trees. These regions lack the moderating influence of the sea and experience even more extreme highs and lows. In summer, gardeners experience over a month of 24-hour sunlight and temperatures above 80°F (27°C). Fortunately, the long summer days bring an advantage because plants can photosynthesize for most of the day and night.

Sub-Arctic and Arctic regions near the coast experience a more maritime climate. The cold sea keeps extreme lows and highs more moderate. Gardeners in these regions feel the long sunlight hours but miss out on the heat because of the cold winds from the ocean. 

How to Know When to Start Seeds

Gardening in these zones isn’t for the novice gardener. It takes plenty of patience, knowledge of your environment, and extra care to get it right. However, once you dial it all in, creating a thriving garden in zone 2 is totally possible. 

Knowing when to start your seeds is the biggest challenge. You’ll want to use every technique in the book to extend your growing season. This includes starting your seeds indoors before the last frost and warming the soil. 

You’ll also need to know when the average first and last frost occurs. This is tricky in such an extreme climate. For example, gardeners in Fairbanks, Alaska (2a and 2b), can expect their average last frost in late May to early June. In the fall, the first frost typically arrives after mid-August. 

What You’ll Need

You’ll want to start seeds indoors. To do this, you’ll first need indoor grow lights. You’ll also need a few deep trays, a seed starter mix, your favorite seed packets, and gardening tools. 

LED grow lights will give your seedlings an extra head start before the start of the growing season. They are compact and adjust as your seedlings grow taller. 

Outside, consider using row covers in the spring. These sheets of material protect your young plants from early summer cold winds and dreaded late-season freezes. A cold frame affixed over a raised bed offers even better protection from snap freezes, ice, and snow.

Best Time to Start Seeds

Now, the hard part! Once you’ve got all your equipment and seeds prepared, it’s time to figure out when to start your seeds. Every species and variety has an average time between sowing and planting. You’ll need to consider this timeframe and the average date of the last frost.

If you’re too late, your plants will miss out on the never-ending summer sunshine. Too early, and they’ll mature indoors before the last frost. Once your seedlings have a few fully developed leaves and roots established in the soil, they’re ready for transplanting outside. 

The timing also depends on if you’re starting your seeds indoors or sowing outdoors. Growing anything other than a native perennial outdoors takes good timing, patience, and a lot of horticultural skills. 

When to Start Seeds Indoors in the Spring

Starting seeds indoors gives you a huge advantage in what you can grow. Annual flowers such as sunflowers, cosmos, and Nasturtium take less than six weeks from sowing to planting. 

Start cold-hardy annuals that take around four to six weeks from sowing to planting about seven weeks before the first frost. These include kale, broccoli, and cabbage. Cucumber, melon, and squash take around three to four weeks, so start them a little later. 

Once you plant your young plants outside, use row covers to protect them as they grow. Row covers shield your plants from sudden frosts and cold temperatures, sometimes up to 6°F. They are also translucent and let in over 90% of the sun’s rays. Pair them with mulch for even more cold protection outside. 

As always, keep a seed journal. List the average germination times, species and varieties that do well, and things you could improve. It’s also great to highlight the things you learned to help other gardeners gardening in your area. 

When to Sow Seeds Outdoors in the Spring

Because you’re gardening in one of the most inhospitable places on Earth, sowing seeds outdoors is a big challenge. You’ll have the best luck with cold-hardy annuals such as beets, radish, and kohlrabi. These plants grow quickly and can handle a bit of cold weather. 

Some plants can’t handle the stresses of transplanting. For these plants, skip the indoor germination and sow them directly in the ground in spring. After sowing, keep the seeds moist but not waterlogged. 

When to Start Seeds for Fall Harvests

Fall comes and goes fast in zone 2. You’ll have to act quickly because the first frost usually arrives by late August or early September if you’re lucky. 

Choose cold-hardy winter crops such as kale, spinach, and mustard greens. Plant them in June or July to harvest just after the first frost. One of the best crops to seed for fall harvest is winter cress. It adds a beautiful touch of yellow to your sub-arctic garden and tastes delicious! 

For extra cold protection, cover your fall crops with floating row covers. These sheets of material will help insulate your plants when the cold Arctic winds arrive. Lay down mulch around the bases of the plants to add even more insulation.