When to plant · 29 cities · zones 6a–6b
When to plant tomatoes in Michigan
Start Roma Tomato seeds indoors around Mar 22 and transplant around May 10 — the Michigan statewide median, counted from a last spring frost of May 3 across 988 ZIP codes and 196 NOAA stations.
The rule: Six weeks indoors at 75–85 °F soil, then transplant a week after the last frost and cage at transplant.
Michigan tomatoes, by cultivar
Statewide median last frost May 3, first fall frost Oct 14, 2027 season. Each cultivar's own indoor lead time and days to maturity, same engine as the Plan Builder.
| Cultivar | Start indoors | Plant out | First harvest | Days |
|---|---|---|---|---|
| Roma TomatoRoma VF (determinate paste) | Mar 22 | May 10 | Jul 24 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Mar 22 | May 10 | Jul 29 | 80 from transplant |
Tight means first harvest lands within two weeks of the median first fall frost. Statewide dates are the ZIP-weighted median of every NOAA 1991–2020 station Michigan's ZIP codes resolve to; 4 of 992 ZIPs have no datable freeze and are left out.
Tomatoes in Michigan, city by city
Roma Tomato, scheduled from each city's nearest NOAA station — the same dates as its frost page.
| City | Last frost | Start indoors | Plant out | First harvest |
|---|---|---|---|---|
| Detroitzone 6b | Apr 27 | Mar 16 | May 4 | Jul 18 |
| Grand Rapidszone 6a | Apr 29 | Mar 18 | May 6 | Jul 20 |
| Warrenzone 6b | Apr 21 | Mar 10 | Apr 28 | Jul 12 |
| Sterling Heightszone 6b | Apr 30 | Mar 19 | May 7 | Jul 21 |
| Ann Arborzone 6a | May 5 | Mar 24 | May 12 | Jul 26 |
| Lansingzone 6a | May 1 | Mar 20 | May 8 | Jul 22 |
| Dearbornzone 6b | Apr 27 | Mar 16 | May 4 | Jul 18 |
| Livoniazone 6b | May 1 | Mar 20 | May 8 | Jul 22 |
| Troyzone 6b | Apr 26 | Mar 15 | May 3 | Jul 17 |
| Farmington Hillszone 6a | May 1 | Mar 20 | May 8 | Jul 22 |
| Westlandzone 6b | May 1 | Mar 20 | May 8 | Jul 22 |
| Flintzone 6a | May 3 | Mar 22 | May 10 | Jul 24 |
| Wyomingzone 6a | Apr 29 | Mar 18 | May 6 | Jul 20 |
| Rochester Hillszone 6a | Apr 26 | Mar 15 | May 3 | Jul 17 |
| Southfieldzone 6b | May 1 | Mar 20 | May 8 | Jul 22 |
| Kalamazoozone 6a | Apr 28 | Mar 17 | May 5 | Jul 19 |
| Novizone 6a | May 1 | Mar 20 | May 8 | Jul 22 |
| Pontiaczone 6a | Apr 26 | Mar 15 | May 3 | Jul 17 |
| Taylorzone 6b | Apr 20 | Mar 9 | Apr 27 | Jul 11 |
| Dearborn Heightszone 6b | May 1 | Mar 20 | May 8 | Jul 22 |
| Royal Oakzone 6b | Apr 26 | Mar 15 | May 3 | Jul 17 |
| St. Clair Shoreszone 6b | Apr 29 | Mar 18 | May 6 | Jul 20 |
| Kentwoodzone 6a | Apr 29 | Mar 18 | May 6 | Jul 20 |
| Battle Creekzone 6a | Apr 30 | Mar 19 | May 7 | Jul 21 |
| Portagezone 6a | Apr 28 | Mar 17 | May 5 | Jul 19 |
| East Lansingzone 6a | Apr 28 | Mar 17 | May 5 | Jul 19 |
| Rosevillezone 6b | Apr 29 | Mar 18 | May 6 | Jul 20 |
| Saginawzone 6a | Apr 29 | Mar 18 | May 6 | Jul 20 |
| Midlandzone 6a | Apr 29 | Mar 18 | May 6 | Jul 20 |
What Michigan tomatoes need
Roma Tomato Seed (300+)
The determinate paste tomato: it ripens most of its crop inside a three-week window. That is a liability for eating and an enormous advantage for sauce day.
San Marzano Tomato SeedMust have
The paste tomato Italian canners actually use. Low seed cavity, low water, high pectin: it reduces to a sauce in half the time a slicer takes and never tastes thin.
Organic Seed Starter Potting MixMust have
Seed-starting mix is not potting soil with a nicer label — it is finer, lighter, and low in nutrients on purpose, because a seedling's first roots want air and moisture, not fertiliser.
Seedling Heat Mat + Digital ThermostatMust have
Peppers germinate on soil temperature, not air temperature. At 65 °F a habanero takes a month and half of them rot; at 85 °F it is up in eight days. The thermostat is the half that matters.
T8 Full-Spectrum Grow Lights, 1 ft 4-packMust have
A south window in March delivers a fraction of the light a pepper seedling needs, and the plant tells you by stretching. Two inches of LED above the canopy for 16 hours a day fixes it permanently.
72-Cell Trays with 1020 Bottoms, 5-PackMust have
The cheap black nursery trays crack after one season and flex enough to break roots when you lift them. These do not. Over five seasons the price per use is lower than the throwaways.
5-Gallon Fabric Grow Bags, 5-Pack
Fabric pots air-prune roots and drain faster than a plastic pot can, which is the entire reason container tomatoes fail. Five gallons is the honest minimum for a pepper; a tomato wants ten.
Ocean Forest Potting SoilMust have
Pre-charged with enough nutrition to carry a transplant for its first month without feeding, which is exactly the window when most container plants stall.
Organic Tomato-Tone 3-4-6 with 8% CalciumMust have
The NPK ratio is the point: low nitrogen, higher potassium. Feed a tomato a high-nitrogen lawn fertiliser and you get a magnificent six-foot plant with four tomatoes on it.
Rot-Stop Blossom End Rot Concentrate
Blossom end rot is almost never a soil calcium shortage — it is a calcium *transport* failure caused by inconsistent water. A foliar calcium spray buys time while you fix the watering, which is the real cure.
58" Square Tomato Cages, 3-PackMust have
The conical wire tomato ring from the hardware store is 33 inches tall and an indeterminate San Marzano will laugh at it in July. Height and square geometry are what actually hold a loaded plant.
Drip Irrigation System with Timer, 16 Nozzles
Blossom end rot, split tomatoes and bitter fruit all trace back to the same thing: water that swings. A $50 timer removes the human from the loop and removes the swing.
Captain Jack Copper Fungicide, 16 oz
Early blight and septoria arrive with a wet July and work up the plant from the bottom. Copper is preventative — sprayed after you see it, you are already losing.
Thuricide BT Concentrate, 16 oz
Bacillus thuringiensis kills caterpillars and nothing else. For tomato hornworms — which can strip a plant in 48 hours — it is the most targeted tool that exists.
Stainless Steel Food Mill, 3 discsMust have
A blender pulverises tomato skins and seeds into the sauce, which is where bitterness comes from. A mill separates them out — no blanching, no peeling, no ice bath. It removes an entire hour from sauce day.
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Tomatoes in Michigan: questions
When should I plant tomatoes in Michigan?
Transplant around May 10 at the statewide median; across the state that date runs from May 3 in the warmest tenth of Michigan's ZIP codes to May 30 in the coldest. To cut the freeze risk to one year in ten, count from May 20 instead of the median last frost. Use the city table for your own town.
When do I start tomatoes seeds indoors in Michigan?
Around Mar 22 for Roma Tomato: 6 weeks before the statewide median last frost, on soil held at 75–85 °F.
When is the last frost in Michigan?
The ZIP-weighted median of NOAA 1991–2020 station medians is May 3. In the warmest tenth of Michigan's ZIP codes the median last frost falls on or before Apr 26; in the coldest tenth, on or after May 23.
When will Michigan tomatoes be ready to harvest?
Roma Tomato planted on the statewide date is ready around Jul 24: 75 days from transplant.
More for Michigan
- When to plant peppers
- When to plant tomatillos
- When to plant basil
- When to plant onions
- When to plant cilantro
- When to plant carrots
- When to plant mustard greens
Tomatoes in every state → · Michigan frost dates → · How frost-date math works →