15 January 2015, by Barbara Pleasant
As spring begins to approach, it’s natural for gardeners to get the itch to plant, even though winter may still have a few weeks to go. While my garden soil will likely remain frozen until March, I start planting indoors under grow lights by mid-January. Over the last seven years, I’ve found consistent success with five vegetables that thrive when started indoors in midwinter: leaf lettuce, sweet alyssum, bulb onions, seed-sown shallots, and kale. Although each plant has its specific needs, it’s worth the effort for a healthy garden.
It’s important to note that warm-weather crops like tomatoes should not be started too early. These plants will not grow properly until the soil warms up, so it’s best to wait until six weeks before your last frost date to start them indoors.
Additionally, growing vegetables indoors during late winter requires a grow light. Most vegetables are full-sun plants, and winter days are too short and cloudy for even the sunniest windows to provide enough light. This year, after replacing the bulbs and ballasts in my 10-year-old fluorescent grow light shelf, my seedlings are thriving, and I can see the difference. Plants are essentially solar-powered, and having proper lighting is crucial to their growth.
Super Early Seed Starting: What to Begin First
1. Leaf Lettuce
The first seeds I sow each year are small pinches of leaf lettuce. I plant them in translucent salad containers, and twice-daily waterings keep the seedlings growing fast. After about four weeks, the tender greens are ready to harvest. I use scissors to trim the lettuce by holding the containers sideways over a colander. The plants quickly begin growing new leaves once they’re returned to their place under the lights. I then start hardening them off before transplanting them into the garden. Once planted, I protect them with cloches or tunnels until they are ready to harvest, or until the weather settles.
To transplant lettuce that has grown into a mat, I use a serrated knife to cut the root mass into small sections rather than trying to separate individual plants. This same technique works well for sweet alyssum, a small flower that tolerates cold and attracts beneficial insects. I grow a few patches of sweet alyssum indoors to transplant into garden beds and containers.
2. Onions and Shallots
Starting onions from seed offers the benefit of reducing bolting compared to using sets. The seedlings are easy to grow, and starting them early leads to larger, healthier bulbs. The longer onions grow before forming bulbs, the bigger and better they will be. If you’re new to growing onions from seed, you can check out my previous blog post on top tips for successful onion cultivation.
Shallots are another great choice for early sowing. They store well for months and are perfect for adding just a bit of onion flavor to dishes. While many gardeners plant shallot bulbs in the fall, I prefer sowing them from seed, as they’re more reliable in my climate. Shallot seedlings tend to stand stiffer and are easier to handle than bulb onion seedlings. All onion family seedlings, including leeks and scallions, are hardy and resilient.
3. Kale
Kale, particularly vigorous varieties like ‘Red Russian’, benefits from an early start. It can be transplanted into cold soil as long as it’s protected from the wind using a cloche or hoop tunnel. When the soil warms up in late spring, kale will experience explosive growth and can be harvested generously in May and June.
Final Thoughts
These five plants are a great starting point for your early winter seed starting. They will keep you busy while you wait for the larger planting season to begin. Keep in mind that grow light space will become limited soon, as cabbage and other cool-weather crops will also need their turn under the lights. This is just the beginning of your seed-starting adventure—there’s much more fun to come!