This calendar covers zones 6a–6b (southern Michigan including Detroit, Grand Rapids, Lansing). Northern Michigan zones 5b and 4a–5a: shift all outdoor direct-sow dates 2–3 weeks later. Zone 6b (Detroit): you can start 1–2 weeks earlier on most dates.
| Month | Start Indoors | Direct Sow Outdoors | Transplant Outdoors | Harvest / Notes |
|---|---|---|---|---|
| January | Onions, leeks (late Jan) | — | — | Plan rotations, order seeds |
| February | Peppers, eggplant, early celery | — | — | Repair tools, chit seed potatoes |
| March | Tomatoes, brassicas, herbs (mid-March) | Spinach, arugula, peas (late March) | Overwintered onion sets | Soil test this month |
| April | Cucumbers, squash (late April), basil | Carrots, beets, lettuce, radishes, potatoes | Broccoli, cabbage (after April 15) | First spinach harvests possible |
| May | — | Beans, corn (after last frost) | Tomatoes, peppers after May 10 (6a) / May 1 (6b) | Harvest peas, lettuce, radishes |
| June | — | Cucumbers, squash, beans (succession) | Basil, sweet potato slips | Harvest broccoli, first zucchini |
| July | Fall broccoli, cabbage (early July) | Succession beans, carrots | — | Peak harvest — tomatoes, cucumbers, beans |
| August | Fall lettuce, spinach transplants | Arugula, spinach, turnips, kale | Fall broccoli, cabbage transplants | Harvest garlic, dry herbs |
| September | — | Spinach, winter radishes | Fall lettuce transplants (early Sept) | Main potato harvest, save seeds |
| October | — | Garlic cloves for next year | — | Final harvests, spread compost |