When to Start Seeds in Zone 1

If you live in the tundra of Alaska or Canada, you can still grow beautiful plants when the ice thaws and sunlight shines for days. These plants need to withstand the coldest temperatures on earth for most of the year. But for a month or two, they’ll have plenty of sunlight to work with. 

If you’re up for the challenge, you can try growing these extra cold-hardy plants by seed, both indoors and outdoors. The easiest choices are native perennials or hardy annuals adapted to your climate. 

Whether you’re growing Siberian irises or common greens like broccoli or spinach, you can start many plants from seed. To grow them successfully, you’ll have to be quick and efficient to get the most out of this extremely short growing season. 

Where Is Zone 1?

The USDA divided the US into 13 distinct zones based on their average lowest winter temperature. Each one is split into full zones of 10°F and half zones of 5°F. The warmest zone is zone 13, and the coldest is zone 1. 

Zone 1 is located in the northern and central regions of Alaska and Canada. These northern regions have some of the coldest temperatures on the planet. Canada’s Yukon Territory experienced North America’s coldest temperature of -81.4°F (-63°C) in 1947. Most winter averages are below -36.4°F (-38°C). 

There are very few cities and towns in this zone and even fewer gardeners. In Canada, this includes Whitehorse, Churchill, and Yellowknife. Towns in the US with this climate zone include: 

• Bettles, Alaska
• Fort Yukon, Alaska 
• Mcgrath, Alaska

What Is the Climate in Zone 1?

Zone 1 regions are sub-arctic tundras with few trees and low annual precipitation. These regions have very short growing seasons and long, brutally cold winters. Temperatures stay below freezing for most of the year, making them some of the most difficult regions for gardeners to grow plants. 

These harsh areas are located near or within the Arctic Circle. In these sub-Arctic places, the sun shines for several days to over a month without setting. Similarly, in winter, you can experience a month of almost complete darkness. 

Although winter temperatures are severely cold, summer can be warm. Many of these frigid areas are located away from moderating sea breezes, which keep temperature extremes moderate. Places such as Fort Yukon can briefly experience daytime highs into the 80s (~29°C) and beyond. 

Expect your average last frost in or just before June, but be prepared for frigid days well into summer. The first frost usually comes in late August. This gives you only one to two months or frost-free days to work with. 

However, one key advantage of these far northern zones is extended daylight. As you near the Arctic circle, summer sunshine increases to 20-24 hours per day. This means that your plants can photosynthesize in double time, growing twice the usual size under abundant sunlight.

How to Determine When to Start Seeds

Timing is everything when sowing seeds in this harsh climate. If you start your seeds too early, your seedlings will already outgrow their containers before it’s time to plant them. Too late, and you’ll miss the narrow window of warm weather and sunshine. 

The first piece of information you need is the last average frost date. Some crops, such as kale and cabbage, are cold-hardy and can withstand a bit of frost. Native perennials are also able to withstand a little frost. 

Transplant your hardier seedlings outdoors a few weeks to a week before the last frost. This is the sub-arctic, so pay attention to cold snaps. Try using row covers and hoop houses to protect them from the frost. A cold frame affixed over a raised bed is even better.

Less hardy annuals, such as chard, radish, and turnips, should go out after the last frost. Check your seed packets for detailed planting instructions for your particular variety. 

When to Start Seeds

As you can see, you can actually garden in zone 1! It’s not easy, but with a few extra steps, you’ll be able to enjoy many flowers, fruits, and vegetables during the short summer. Starters are harder to find in these remote locations, so you’ll probably have to grow your plants from seed. 

When growing seeds, timing is crucial and dependent on what you’re trying to grow. For some crops that take over 80 days until harvest, you’ll probably want to sow your seeds in mid-April. For crops that take over 100 days, such as onion and Brussels sprouts, mid-March is usually a good starting point. 

When to Start Vegetable and Flower Seeds Indoors in the Spring

As a general rule, start most seeds four to six months before the last frost. Because of the short growing seasons and unpredictable frosts, you’ll have to start your seeds indoors unless you’re growing a native perennial. 

To do this, you’ll need a tray, preferably one that’s deep enough for your seedlings to establish themselves securely in the soil. Next, you’ll need growing media, such as seedling mix or potting soil. To get your seeds to germinate, try using a germination dome to trap heat and moisture. 

Once you planted your seeds in their media, it’s time to provide an energy source. Sunlight is scarce when you start your seeds in this unforgiving landscape. To get around this, try using indoor grow lights. These lights will give your seeds the energy they need until they’re ready for transplanting outside. 

Once they’re ready, harden them off and plant them outside on a sunny day after the last frost. Use row covers and mulch to protect them from late-season frosts and cold spells. 

When to Sow Seeds Outdoors in the Spring

If you’re a zone 1 gardener, it will be tricky to get annuals to mature if you sow them directly outdoors. Some fast-growing and cold-hardy exceptions may be radish and beets. These vegetables germinate quickly and have a low germination temperature. 

Because of the frigid temperatures and extremely short growing seasons, only a few flowers and vegetables can survive outside. Select seeds that have a short maturation period and carefully follow the directions on your seed packet for spring planting. 

As mentioned above, the last frost in zone 1 usually falls between late May and mid-June. For cold-hardy vegetables such as broccoli and kale, you can sow a week or two before the last frost. Keep some native plants, such as soapberry (Shepherdia canadensis), in moist peat soil in winter to cold stratify and sow in late spring. 

Some species of apples, including ‘Patterson’ and ‘Heyer #12’ will thrive in this cold climate. Zone 1 suitable apples usually have rootstocks from cold-hardy crab apples. This lets them survive the harsh elements.

When to Start Seeds for Fall Planting Outdoors

Fall is a relative concept in these extreme climates. Many locations experience a seasonal transition in a few weeks or less. Once the first frost arrives, it’s usually the start of the long and brutal winter. For many regions in zone 1, the first frost usually arrives by August. 

Start fast-growing vegetables such as radish, spinach, and kale in late June. You should get a good harvest before the first frost. Check the average days to maturity for your seeds before planting. 

Some native perennials, such as alpine arnica (Arnica alpina) and Labrador tea (Ledum palustris) need fall planting to grow. Once you’ve harvested your last late-season vegetables, you can prepare your garden to grow these vibrant cold-hardy flowers and shrubs. 

Most native perennials need to be exposed to the cold before germinating. This process is called cold stratification. Plants such as snow arnica (Arnica frigida) and common alplily (Lloydia serotina) need cold stratification and fall sowing. 

Some native fruits, such as the dwarf blueberry (Vaccinium caespitosum), also go in the ground in fall. Keep their seeds moist but not waterlogged until the winter sets in. Once spring arrives, your native plants should start to germinate.