When to plant · 38 cities · zones 5b–6a
When to plant tomatillos in Illinois
Start Tomatillo seeds indoors around Mar 6 and transplant around Apr 24 — the Illinois statewide median, counted from a last spring frost of Apr 17 across 1,402 ZIP codes and 192 NOAA stations.
The rule: Six weeks indoors, transplant after the last frost, and give each plant 30 inches and a large cage.
Illinois tomatillos, by step
Statewide median last frost Apr 17, first fall frost Oct 21, 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 |
|---|---|---|---|---|
| TomatilloToma Verde | Mar 6 | Apr 24 | Jul 3 | 70 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 Illinois's ZIP codes resolve to.
Tomatillos in Illinois, city by city
Tomatillo, scheduled from each city's nearest NOAA station — the same dates as its frost page.
| City | Last frost | Start indoors | Plant out | First harvest |
|---|---|---|---|---|
| Chicagozone 6a | Apr 10 | Feb 27 | Apr 17 | Jun 26 |
| Aurorazone 5b | Apr 19 | Mar 8 | Apr 26 | Jul 5 |
| Napervillezone 5b | Apr 28 | Mar 17 | May 5 | Jul 14 |
| Jolietzone 5b | Apr 19 | Mar 8 | Apr 26 | Jul 5 |
| Rockfordzone 5b | Apr 24 | Mar 13 | May 1 | Jul 10 |
| Elginzone 5b | Apr 26 | Mar 15 | May 3 | Jul 12 |
| Springfieldzone 6a | Apr 15 | Mar 4 | Apr 22 | Jul 1 |
| Peoriazone 6a | Apr 16 | Mar 5 | Apr 23 | Jul 2 |
| Champaignzone 6a | Apr 15 | Mar 4 | Apr 22 | Jul 1 |
| Waukeganzone 6a | Apr 30 | Mar 19 | May 7 | Jul 16 |
| Cicerozone 6a | Apr 11 | Feb 28 | Apr 18 | Jun 27 |
| Bloomingtonzone 6a | Apr 21 | Mar 10 | Apr 28 | Jul 7 |
| Schaumburgzone 5b | Apr 30 | Mar 19 | May 7 | Jul 16 |
| Evanstonzone 6a | Apr 26 | Mar 15 | May 3 | Jul 12 |
| Arlington Heightszone 6a | Apr 19 | Mar 8 | Apr 26 | Jul 5 |
| Bolingbrookzone 6a | Apr 20 | Mar 9 | Apr 27 | Jul 6 |
| Decaturzone 6a | Apr 14 | Mar 3 | Apr 21 | Jun 30 |
| Palatinezone 5b | Apr 25 | Mar 14 | May 2 | Jul 11 |
| Skokiezone 6a | Apr 26 | Mar 15 | May 3 | Jul 12 |
| Des Plaineszone 6a | Apr 16 | Mar 5 | Apr 23 | Jul 2 |
| Orland Parkzone 6a | Apr 20 | Mar 9 | Apr 27 | Jul 6 |
| Oak Lawnzone 6a | Apr 10 | Feb 27 | Apr 17 | Jun 26 |
| Mount Prospectzone 6a | Apr 19 | Mar 8 | Apr 26 | Jul 5 |
| Berwynzone 6a | Apr 11 | Feb 28 | Apr 18 | Jun 27 |
| Tinley Parkzone 6a | Apr 23 | Mar 12 | Apr 30 | Jul 9 |
| Wheatonzone 5b | Apr 28 | Mar 17 | May 5 | Jul 14 |
| Normalzone 6a | Apr 25 | Mar 14 | May 2 | Jul 11 |
| Oak Parkzone 6a | Apr 11 | Feb 28 | Apr 18 | Jun 27 |
| Hoffman Estateszone 5b | Apr 30 | Mar 19 | May 7 | Jul 16 |
| Downers Grovezone 6a | Apr 28 | Mar 17 | May 5 | Jul 14 |
| Plainfieldzone 5b | Apr 20 | Mar 9 | Apr 27 | Jul 6 |
| Glenviewzone 6a | Apr 19 | Mar 8 | Apr 26 | Jul 5 |
| Elmhurstzone 6a | Apr 16 | Mar 5 | Apr 23 | Jul 2 |
| Lombardzone 6a | Apr 28 | Mar 17 | May 5 | Jul 14 |
| Buffalo Grovezone 6a | Apr 19 | Mar 8 | Apr 26 | Jul 5 |
| Molinezone 5b | Apr 24 | Mar 13 | May 1 | Jul 10 |
| Crystal Lakezone 5b | May 1 | Mar 20 | May 8 | Jul 17 |
| Romeovillezone 6a | Apr 20 | Mar 9 | Apr 27 | Jul 6 |
What Illinois tomatillos need
Toma Verde Tomatillo SeedMust have
Salsa verde is not a green tomato sauce — it is a tomatillo sauce, and the difference is the tartness and the natural pectin that makes it cling. There is no substitute.
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.
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.
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.
Garden Harvest Basket with Tool Caddy
A harvest basket that doubles as a colander means the hose rinse happens in the garden, and the dirt stays outside. On a 20-pound tomato day that is a genuine time saving.
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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Tomatillos in Illinois: questions
When should I plant tomatillos in Illinois?
Transplant around Apr 24 at the statewide median; across the state that date runs from Apr 14 in the warmest tenth of Illinois's ZIP codes to May 4 in the coldest. To cut the freeze risk to one year in ten, count from May 3 instead of the median last frost. Use the city table for your own town.
When do I start tomatillos seeds indoors in Illinois?
Around Mar 6 for Tomatillo: 6 weeks before the statewide median last frost, on soil held at 75–85 °F.
When is the last frost in Illinois?
The ZIP-weighted median of NOAA 1991–2020 station medians is Apr 17. In the warmest tenth of Illinois's ZIP codes the median last frost falls on or before Apr 7; in the coldest tenth, on or after Apr 27.
When will Illinois tomatillos be ready to harvest?
Tomatillo planted on the statewide date is ready around Jul 3: 70 days from transplant.
More for Illinois
- When to plant tomatoes
- When to plant peppers
- When to plant basil
- When to plant onions
- When to plant cilantro
- When to plant carrots
- When to plant mustard greens
Tomatillos in every state → · Illinois frost dates → · How frost-date math works →