Ever wonder why some gardeners set out stocky, deep-green transplants in May while others are nursing pale, floppy seedlings that tip over at the first breeze? Most of the time it comes down to the setup, not the seed. In this guide, you'll learn how to put together a simple indoor seed-starting station now, while the garden's asleep, and how to figure out exactly when to start each crop next spring.
Why set up your seed-starting station in November?
The first seeds of the season go in sooner than most people think. Onions, leeks and celery need 10 to 12 weeks indoors before transplanting, so in cold climates they're sown in late winter. If you wait until then to hunt for shelves, lights and trays, you're scrambling.
Setting up now gives you time to gather what you need without rushing, test your lights and timer, and fix any problems before the seeds that matter go in. It's also a good excuse to go through your seed stash and see what you have.
What do you need for a basic indoor setup?
You don't need a greenhouse or anything fancy. A corner of a basement, spare room or laundry area works fine as long as it stays around 60 to 70°F.
- Shelving: A sturdy wire shelf unit is ideal, because you can hang lights from each shelf and adjust the height as seedlings grow.
- Lights: Plain LED shop lights work well. A winter windowsill, especially up north, doesn't give seedlings enough light, and that's the number-one cause of leggy plants.
- Timer: An inexpensive outlet timer keeps lights on for a steady 14 to 16 hours a day without you having to remember.
- Trays and cells: Cell trays or small pots with drainage holes, set inside a solid tray so you can water from below. Reusing old trays? Scrub them and soak in a solution of 1 part bleach to 9 parts water first.
- Seed-starting mix: Use a light, fine mix made for seeds, never garden soil, which packs down and can carry disease.
- Heat mat (optional): Peppers and tomatoes sprout much faster with warm soil. Onions and leeks don't need one.
- A small fan: Gentle moving air builds sturdier stems and helps keep damping-off away.
How do you set it up so seedlings grow strong?
Hang your lights so you can raise them on chains or hooks. Keep LEDs about 2 to 4 inches above the tops of the seedlings and move them up as the plants grow. If seedlings start stretching and leaning, the light is too far away.
Pre-moisten your mix before filling the cells; it should feel like a wrung-out sponge. Sow seeds at the depth listed on the packet, usually about two to three times the seed's width. A clear dome or plastic wrap keeps humidity up until sprouts appear, then take it off right away.
Once your seedlings are up:
- Water: Water from below by adding water to the bottom tray, and let the top of the mix dry slightly between waterings.
- Temperature: Germinate peppers at about 80 to 85°F soil temperature, then grow them on at 65 to 75°F. Onions and leeks are happy at room temperature.
- Air: Run your fan on low for a few hours a day, pointed so the seedlings just barely sway.
- Feed: Once true leaves appear, feed with a half-strength liquid fertilizer about once a week unless your mix already includes nutrients.
When should you start each crop?
Don't go by a date on a calendar. Find your average last spring frost date, then count backward:
- Onions, leeks and celery: 10 to 12 weeks before last frost
- Peppers and eggplant: 8 to 10 weeks before last frost
- Tomatoes: 6 to 8 weeks before last frost
- Broccoli and cabbage: 6 to 8 weeks before last frost; they can go out a few weeks before it
Cold-climate note: Here in Minnesota (zone 5a), the last frost usually lands around mid-May, so onions and leeks go in around late February to early March. Gardeners in zones 3 and 4 may be closer to late May or early June, so count from your own date.
Which seeds should you plan to start first?
These slow growers are the ones that make an indoor setup worth it:
- Yellow Sweet Spanish Onion (about 110 days from transplant): Big, round, mild bulbs that are great raw, grilled or in salsa. It's a long-day onion, so it suits northern gardens.
- American Flag Leek (about 120 to 130 days from seed): Long white shanks with a sweet, mild onion flavor for soups and sautés. Very cold-hardy, so it can stay in the garden well into fall.
- California Wonder Pepper (about 70 to 75 days from transplant): Thick-walled, blocky bells you can pick green or wait for red. A reliable choice for stuffing and slicing.
For filling your cells, the Elite Seed and Clone Soil is a light mix of coco coir, peat, perlite and compost with nutrients built in, so you won't need to feed as early.
Can you test your setup this winter?
Absolutely, and I'd recommend it! Sow a tray of lettuce under your new lights. It'll show you whether your light height and watering routine are working, and you'll get fresh leaves for winter salads. Buttercrunch and Red Salad Bowl are good picks for this. I love making salads with freshly harvested greens, and that's a real treat in a Minnesota January.
Every packet of 99Heirlooms seed is non-GMO, and I pack each one myself here in-house.
Ready for a strong start
A few shelves, a couple of lights and a timer are all it takes to grow healthy transplants of your own. Get your station set up over the next few weeks, do a test run, and you'll be ready when it's time to sow those first onion seeds. You've got this.