January garden tasks: Midwest

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Test old seed before you order

Sort through leftover seed packets before buying new ones. Kept cool and dry, most vegetable seed holds up for a few years, but germination falls with age, and onion, leek and parsnip seed fade fastest. Illinois Extension recommends a simple ragdoll test:

1. Roll 10 seeds into a damp paper towel and put it in a labeled plastic bag.
2. Keep the bag somewhere warm (70–80°F suits most vegetables) and check daily.
3. After the germination time on the packet, count the sprouts. Seven sprouts means 70% germination. Sow more thickly to compensate, or replace seed that tests poorly.

Store seed in a sealed jar in a cool, dry spot. A basement shelf or the refrigerator door works. Humidity and heat do the most damage.

Order seed and plan the garden

Order in January. Popular varieties, seed potatoes, onion plants and sets, and asparagus crowns sell out by early spring. Purdue's January garden calendar puts catalog review and garden planning at the top of the month's list.

• Match days to maturity to your season. In zones 3–4, with a last frost around mid-May and first frost in late September or early October, choose early-maturing tomatoes, peppers, melons and winter squash. Zone 6 gardeners have more choice.
• Look for disease resistance to the problems you have had: early blight and septoria on tomatoes, powdery mildew on cucurbits, and scab on apples and crabapples if you are buying trees.
• Rotate crop families. Keep tomatoes, peppers, eggplant and potatoes (one family), squash and cucumbers, and cabbage-family crops out of the beds they occupied last year.
• Order bare-root fruit and trees now for spring delivery. Bare-root stock gets planted as soon as the soil can be worked in spring.

Build your seed-starting calendar

Every indoor sowing date counts back from your average last frost. As the March guide notes, Minneapolis (zone 4) averages around May 7, Chicago around April 22, Des Moines and Milwaukee from late April to early May, and Kansas City and St. Louis around April 7–15. Check yours with the frost date tool.

Typical lead times from the seed packet and Extension guidance:

• Onions and leeks: 10–12 weeks before last frost. Iowa State Extension puts onion sowing for Iowa in February. In zone 6 it can start in late January, and in zone 4 it slides to late February.
• Peppers and eggplant: 8–10 weeks before. Late February in zones 5–6, early March in zone 4.
• Tomatoes: 6–8 weeks before. Late February to early March in zone 6, mid-March in zone 5, and mid-to-late March in zone 4.
• Cabbage-family transplants: about 4–6 weeks before they go outside, which is a few weeks ahead of the last frost.

Iowa State's Can I start my seeds indoors yet? makes the key point for January: for most vegetables, the answer is not yet. Starting early produces leggy, rootbound transplants rather than an earlier harvest.

Get the seed-starting setup ready

January is a good time to set up equipment, even if sowing waits until February or March:

• Lights: per UMN Extension (as cited in the March guide), seedlings need artificial light 2–3 inches above them for 14–16 hours a day. A Midwest window in late winter is not enough.
• Heat: peppers, eggplant and tomatoes germinate best with soil at 70–80°F. A heat mat helps in a cool basement.
• Medium and containers: buy fresh, sterile seed-starting mix. Wash reused trays and cells in a dilute bleach solution to reduce damping-off.
• Air movement: a small fan on a timer helps produce sturdier stems and reduces disease.

Our seed starting guide covers the full setup, and winter sowing is a no-lights option for hardy perennials and native wildflowers. Michigan State University Extension describes sowing them in covered containers left outdoors in winter.

Check stored bulbs, produce and forced pots

Once a month, go through everything in storage:

• Dahlias, cannas, gladiolus, tuberous begonias: per Michigan State University Extension, store them cool, dark and frost-free. Throw out anything soft, moldy or rotting. If tubers are shriveling, lightly moisten the packing material. If they are damp, let it dry. See overwintering dahlias.
• Overwintering geraniums and other tender perennials: water sparingly and pinch leggy growth. See overwintering tender perennials.
• Squash, potatoes, onions: remove anything soft or sprouting.
• Pots of forced bulbs: once they have had their full cold period and shoots are a couple of inches tall, bring them into a cool, bright room.

Winter pest scouting on bare branches

With the leaves down, some pest problems are easier to spot in January than at any other time. A walk around the yard on a mild day is worthwhile:

• Ash trees and emerald ash borer: look for patches where woodpeckers have flaked off the outer bark, leaving pale, blond-looking areas high in the canopy. That is often the first visible sign of emerald ash borer. If a valued ash shows it, decide over the winter whether to treat it (insecticide treatments are timed for spring) or plan its removal. See emerald ash borer.
• Spotted lanternfly: in Ohio, Indiana, Michigan and Illinois, check bark, stone, fences and stored outdoor items for the flat, gray, mud-like egg masses. Per Ohio State University Extension, scrape and destroy them, and report finds outside known infested areas.
• Black knot: look for hard, black, swollen galls on plum and cherry branches. Mark them, then cut them out well below the gall during dry weather before spring and throw out the prunings.
• Mummified fruit: shriveled apples, crabapples and plums left hanging on the tree carry disease into spring. Pick them off and throw them out.
• Bagworms on evergreens: hand-pick the hanging bags from junipers and arborvitae. Each one can hold hundreds of eggs.

Outdoor checks after snow and cold snaps

• Rabbits and voles: deep snow lifts rabbits higher on trunks. Make sure guards on young trees and shrubs still clear the snow surface. Fresh, clean-cut gnawing on shrub stems is usually rabbits.
• Salt: keep shoveled snow from salted walks and driveways out of beds, and use sand next to plantings. Salt injury often does not show until summer.
• Snow and ice: brush heavy snow off evergreens from below, and leave ice to melt.
• Heaving: during a January thaw, look for perennials pushed up out of the soil. Press them back once the soil softens and add more mulch.
• Lawn: stay off frozen turf, and do not fertilize frozen ground.
• Pruning: oaks can be pruned now, as covered in the December guide. Dormant pruning of fruit trees and summer-flowering shrubs is best in late winter, from February in zone 6 and March in zones 4–5. Sharpen tools now.

Common mistakes

Frequently asked

Is it too early to start seeds in January in the Midwest?

For almost everything, yes. Onions and leeks are the exception in zone 6, where late January is reasonable because they need 10–12 weeks before transplanting. Zones 4–5 should wait until February or March. Iowa State Extension cautions against starting most vegetables before the recommended weeks-before-transplant timing.

How can I tell if my old seeds are still good?

Run a germination test. Roll 10 seeds in a damp paper towel, keep them warm, and count the sprouts after the time on the packet. Illinois Extension recommends this before deciding to toss or keep older seed.

Can I prune my apple trees in January?

You can remove dead or broken wood, but UMN Extension and the March guide place the best dormant-pruning window in late winter, before bud swell. That is usually March in zones 4–5 and late February to March in zone 6.

My shrubs have chewed bark. Will they survive?

It depends on how far around the stem the damage goes. Bark chewed all the way around a stem (girdling) kills that stem above the wound. Multi-stem shrubs usually regrow from the base, so cut damaged stems back in spring. Protect the rest with guards for the remainder of winter.

Sources

1. Test Seed Viability, University of Illinois Extension
2. January Garden Calendar, Purdue Consumer Horticulture
3. Can I start my seeds indoors yet?, Iowa State University Extension
4. I would like to start some onion plants indoors. When should I sow the seeds?, Iowa State University Extension
5. Digging and Storing Tender Bulbs, Michigan State University Extension
6. Winter Sowing in Containers for Michigan Gardeners, Michigan State University Extension
7. Spotted Lanternfly Update: Winter 2025/2026, Ohio State University Extension, Lucas County

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