March in Michigan is when the real work begins — not in the garden, but under the lights. The ground is still frozen. The snow may or may not be gone. But downstairs, on the seed-starting shelves, the season is already underway.
What to Start Indoors in March
Tomatoes — Start mid-March. This feels late. It is not. Six to eight weeks before last frost (May 15 in Zone 6a) means March 15 to April 1. Resist the urge to start earlier — leggy, rootbound tomatoes never outperform stocky, well-timed ones.
Peppers — If you have not started peppers already, early March is your last good window. They want 8 to 10 weeks indoors. Start them now and they will be sturdy transplants by mid-May.
Herbs — Basil, parsley, and cilantro all start well in March. Basil especially benefits from the warmth of a heat mat during germination.
Flowers — Zinnias, marigolds, and cosmos can all be started in late March for transplanting after frost. Or save yourself the trouble and direct-seed them in late May — both methods work.
What to Do Outside in March
Prune — Fruit trees, grape vines, and berry bushes should be pruned before they break dormancy. Late March, before the buds swell, is ideal.
Clean — Pull any remaining garden debris from last season. Rake back mulch from perennial beds to let the soil warm. Clean and sharpen tools.
Plan — Finalize your garden layout. Order seeds if you have not already. Check last year’s saved seeds for viability — a damp paper towel and a few days will tell you what’s still good. I wrote about that process in Testing Seed Viability.
What NOT to Do in March
Do not transplant anything outside. Do not work the soil — if it clumps when you squeeze it, it is too wet. Do not remove winter mulch from garlic beds. And do not — I cannot stress this enough — start your tomatoes on March 1st. They will hate you by May.
For the full yearly schedule, see the Michigan Zone 6a Garden Planner. For seed starting setup, see Capillary Mats and Grow Lights.
— Chris Izworski, Freighter View Farms, Bay City, Michigan
Chris Izworski is a Michigan gardener, writer, and AI technologist based on Saginaw Bay. He writes at Freighter View Farms about Zone 6a gardening, seed saving, and practical AI in public safety.
Freighter View Farms | Chris Izworski 
Leave a comment