Freighter View Farms | Chris Izworski

March in Michigan is a negotiation. Outside, Saginaw Bay is still gray and cold, and the garden beds are either frozen or muddy depending on the week. The last frost is still six to eight weeks away. None of that matters, because March is not about outside. March is about the basement, and the grow lights, and the trays of tomato seedlings that are already three inches tall and reaching toward warmth.

Here is what to start in March in Zone 6a, and when to start it.

Tomatoes: Mid-March Is Right

This feels late. Every gardening instinct says start earlier. Do not start earlier. Six to eight weeks before last frost — and our last frost in Bay City is around May 15th — puts the ideal tomato start date between March 15th and April 1st. Plants started too early get root-bound, leggy, and stressed before they ever see the garden. A stocky, well-timed transplant will outperform a big, root-bound one every time.

I start Cherokee Purple, Brandywine, Costoluto Fiorentino, and the Orange Accordion in the third week of March. Two or three seeds per cell, thin to the strongest, bottom-water on capillary mats, and keep the soil temperature above 70 degrees — a heat mat under the trays until germination, then the warmest spot under the lights. They are up in five to ten days.

Peppers: First Week of March at the Latest

Peppers want 8 to 10 weeks indoors before transplant. If you have not started them yet as March begins, start them immediately. Shishitos, bells, sweet Italian frying peppers — all of them take longer than you expect and benefit from the full indoor season. Peppers also need consistent warmth to germinate: 80 degrees soil temperature is not excessive. A heat mat is almost required. Without it, germination is slow and uneven.

Herbs: Basil and Parsley in March

Basil started in March will be ready to transplant alongside the tomatoes in mid-May. It does not need a heat mat but appreciates the warmth of the grow light shelf. Start more than you think you need — basil has a way of disappearing between the starting tray and the garden, and more basil is never a problem.

Parsley is slow and stubborn to germinate, which is why starting in March makes sense even though it is a cool-season herb. Soak the seeds overnight before planting and expect two to three weeks before you see anything. Once it is up, it is easy.

What Not to Start in March

Cucumbers, squash, beans, and most direct-sown crops: these want only two to three weeks indoors at most, or can be direct-seeded outside in late May. Starting them in March produces plants that outgrow their containers and become stressed before the garden is ready for them. Wait. The last-frost window comes faster than March makes it seem.

The Work of March

Beyond the seed starting, March is when I do the planning I did not finish in January. The garden layout for the season. The order to the seed companies for anything I did not save myself. The inspection of the raised beds — any repairs needed, how much compost to add before planting, where the black plastic mulch goes to pre-warm the soil.

Outside, the bay is making its slow turn from frozen to open water. The ice goes out in patches, then all at once, and the freighters begin their season again. I watch this from the garden — or from the window over the seed-starting shelf — and take it as the signal I have been waiting for. The season is already underway. We are not waiting for spring. Spring is waiting for us to be ready.

For the full month-by-month breakdown, the Zone 6a planting calendar at chrisizworski.com has every crop from February through October.

Related reading:

• The full seed starting timing calendar: When to Start Seeds Indoors in Michigan.
• All of these March dates are anchored to the last frost — the Michigan Frost Dates post explains the math.