What to plant in January in Illinois
In Illinois (IL), January sits about 14 weeks before the average last frost (April 20). The state averages 177 frost-free days a year (last frost April 20, first frost October 14; USDA zones 5a, 5b, 6a, 6b, 7a).
1 crop has a sowing or planting window this month.
Dates here come from Illinois frost dates (last frost Apr 20, first frost Oct 14). For one crop in detail, see when to plant tomato, lettuce or garlic in Illinois.
Illinois: planting activity through the year
Start seeds indoors in January (1)
Indoor sowings for transplants later. Six to eight weeks under lights is typical for tomatoes and peppers; onions and leeks need longer.
| Crop | What to do | Window | This month |
|---|---|---|---|
| Celeriac | Start seeds indoors | Jan 26 – Feb 9 | Opens Jan 26 |
Planting dates for popular crops in Illinois
Every crop has its own full-year dates for Illinois: indoor start, transplant or direct sowing, and harvest.
A planning month: January garden jobs in Illinois
- Order seed while stock is good. Illinois's average last frost is April 20, so the first indoor sowings begin around January 26 - see starting seeds indoors.
- Sketch this year's beds and move each crop family to a new spot - the garden planner and the crop rotation guide make it quick.
- Test old seed: roll ten seeds in a damp paper towel for a week. If fewer than seven sprout, sow thicker or buy fresh.
- If the ground isn't frozen, spread compost now so it's worked in by spring, and send off a soil test - January is when labs are quiet.
USDA zone chart for Illinois
Illinois spans USDA zones 5a, 5b, 6a, 6b, 7a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average.
Questions gardeners ask
What vegetables can I plant in Illinois in January?
1 crops have a window in January: celeriac. The tables above give the exact dates for each.
Is it too late to plant tomatoes in Illinois in January?
Not too late - it's actually a little early. In Illinois the next tomato window opens around February 23: start seeds indoors.
Is it too late to plant lettuce in Illinois in January?
Not too late - it's actually a little early. In Illinois the next lettuce window opens around March 16: start seeds indoors.
When is the first frost in Illinois?
The statewide average first fall frost is around October 14 and the last spring frost around April 20. Your town can be a week or two either side - look yours up by ZIP code.
What should I start indoors in January in Illinois?
Celeriac (Jan 26 – Feb 9).
What to plant in January in other states
Dates are computed from Illinois’s statewide average frost dates (from NOAA/NCEI climate normals) and each crop’s timing in our crop database. Your garden may be a week or two either side - for dates tuned to your ZIP code, use the planting calendar.