Zone 6 is the great middle of American gardening — the wide belt running from southern New England and Pennsylvania through Ohio, Missouri, and Kansas to the high country of New Mexico. Winters dip to −10…0°F, the last frost usually falls between mid-April and early May, and the first fall frost arrives in early-to-late October. That adds up to a frost-free season of roughly 155–200 days (about 175 in a typical 6b city like Columbus, Ohio): long enough to grow almost everything, short enough that timing still matters. One 2023 note: the updated USDA map moved Pittsburgh, St. Louis, Boston, and Providence into Zone 7a — if that's you, use our Zone 7 calendar.
This calendar walks the Zone 6 year month by month. Every date below is a typical range, not a promise — Zone 6 stretches across half the country, and a valley in 6a can run two weeks behind a city rooftop in 6b. Look up your exact frost dates by ZIP code once (the free Old Farmer's Almanac tool), pencil them in, and shift our ranges to match. How the whole frost-date system works is in our one-chart planting guide.
Zone 6 at a glance
| Fact | Typical for Zone 6 |
|---|---|
| Winter low | −10 to 0°F (6a: −10…−5, 6b: −5…0) |
| Average last spring frost | Mid-April to early May (colder pockets: mid-May) |
| Safe date for tomatoes & tender crops | About May 15 |
| Average first fall frost | Early to late October (mid-October is typical) |
| Frost-free season | ~155–200 days (about 175 in a typical 6b city) |
March — the year starts on the windowsill
- Start indoors: tomatoes and peppers in mid-to-late March (6–8 weeks before their mid-May planting date), plus broccoli, cabbage, and head lettuce.
- Direct sow (late March, warm pockets): peas and spinach can go into workable soil 4–6 weeks before the last frost — in much of Zone 6 that's the last week of March. Raised beds and containers drain and warm earlier than open ground, so these early sowings can often go in a little sooner.
- Onion sets can go in as soon as the soil crumbles instead of smearing.
April — the cool-season month
- Direct sow all month: lettuce, radishes, carrots, beets, kale, chard, turnips, arugula.
- Transplant mid-April: broccoli and cabbage seedlings — they shrug off light frosts.
- Plant potatoes in early-to-mid April, about 2–4 weeks before your last frost.
- The Zone 6 trap: false spring. Nearly every year a run of 75°F April days tempts gardeners to set out tomatoes. Nearly every year early May answers with one last frosty night. Let the soil thermometer and the calendar outvote the weather app.
May — the handoff
- Frost danger fades between May 1 and May 15 depending on your spot.
- Direct sow after your last frost: bush and pole beans, sweet corn, cucumbers, summer squash — once soil hits 60°F.
- Transplant tomatoes around May 15, when nights hold above 50°F; peppers and eggplant prefer the last week of May.
- Mulch everything after planting — it locks in spring moisture and saves summer weeding.
June — fill every gap
- Finish planting warm-season crops by mid-June: melons, winter squash, and sweet potato slips (choose short-season varieties — Zone 6 gives them just enough runway).
- Re-sow lettuce in afternoon shade every two weeks for a steady supply.
- Okra is a maybe in Zone 6 — it works in a hot summer with an early variety, but don't bet the bed on it.
July — think fall while it's hot
- Sow the last round of bush beans by mid-July (50–55-day varieties finish comfortably before frost).
- Start fall broccoli and cabbage seed in trays in a shaded spot in the first days of July (late June is even better), ready to transplant from late July to mid-August.
- Order fall seeds now — spinach and lettuce racks empty out by September.
August — the second spring
Zone 6's fall window is generous: greens, roots, and brassicas sown in August mature in crisp October weather and often taste sweeter for it. Get fall carrots in by about August 1 (late July is better); beets and turnips can go in through mid-August. Lettuce, radishes, and Asian greens work all month; spinach from mid-August, once nights cool. We keep a full zone-by-zone guide to this window in What to Plant in August for a Fall Garden.
September — stretch the season
- Sow spinach early in the month — harvest baby leaves in fall, then let it overwinter under leaves for the earliest spring greens you'll ever cut.
- Last call for radishes and quick lettuce in the first week.
- Spread compost or shredded leaves on finished beds; October-you will be grateful.
October — garlic month
- Plant garlic from mid-October to early November — that's Iowa State Extension's window, and in colder spots the Old Farmer's Almanac suggests about one to two weeks after your first killing frost. Aim for at least three weeks before the ground freezes. Cloves root through the fall and explode out of the gate in March. Depth, spacing, and the no-bend method: our garlic planting guide.
- Keep row covers or old bed sheets handy: the first frost is often followed by two mild weeks, and covered kale, carrots, and lettuce cruise right through.
November — tuck it in
- Last call for garlic in the first week, if the soil is still workable.
- Once the ground starts to freeze, mulch the garlic bed with 4–6 inches of loose, weed-free straw, as Iowa State Extension recommends.
- Harvest the last covered kale and carrots, then pile shredded leaves on empty beds for spring.
The no-bend adjustments for Zone 6
Everything above works at ground level — and works better at waist level:
- Containers warm faster than any garden bed. A dark pot in April sun warms well ahead of open soil, which effectively stretches Zone 6's spring. (In July, switch the thinking: light-colored pots keep roots cooler.)
- Raised beds drain spring mud. March peas in a raised bed mean no kneeling in cold muck — sow standing, from the edge.
- August sowings need daily water for a week — far more pleasant at counter height than at ankle height.
New to either? Start with our raised bed height guide and the container vegetable guide.
Put your Zone 6 dates on paper
The free Printable Garden Planner Kit includes a fill-in planting chart, frost-date tables for zones 3–10, bed grids, and seasonal checklists — all in large, readable print.
Frequently asked questions
When should I plant tomatoes in Zone 6?
Set transplants out in mid-to-late May — around May 15 for most of the zone — once nights stay above 50°F and soil reaches 60°F. Start seeds indoors in mid-to-late March, 6–8 weeks earlier. Planting into cold soil earlier gains nothing; the plants just sulk.
When do I start seeds indoors in Zone 6?
Count back from the outdoor date: tomatoes 6–8 weeks (mid-late March), peppers and eggplant about 8 weeks (mid-March), broccoli and cabbage 4–6 weeks before their mid-April transplanting (early March). Later is safer than earlier — leggy, root-bound seedlings never quite recover.
When can I plant potatoes in Zone 6?
Early-to-mid April, about 2–4 weeks before your last frost. The old-timers' rule of planting "around tax day" lands near the late end of that window.
What's the difference between Zone 6a and 6b?
Five degrees of average winter minimum: 6a bottoms out at −10…−5°F, 6b at −5…0°F. That matters for which perennials and fruit trees survive winter; for the vegetable calendar the difference is small — 6b springs run about 10 days to two weeks ahead of 6a. Note that the USDA redrew the map in 2023 and many gardens shifted a half-zone warmer, so re-check yours.
When should I plant garlic in Zone 6?
Mid-October to early November — Iowa State Extension's window — while the soil is still workable and at least three weeks before the ground freezes. Planted too early it sprouts tall before winter; too late it can't root. October's sweet spot solves both.
Sources
- Virginia Tech Cooperative Extension — Home Garden Vegetable Planting Guide
- Michigan State University Extension — Garden Planning Calendar
- The Old Farmer's Almanac — Frost Dates Calculator
- USDA Agricultural Research Service — Plant Hardiness Zone Map (2023)
- Purdue Extension — Indiana Vegetable Planting Calendar (HO-186-W)
- Iowa State University Extension — When should I plant garlic?