Zone record — updated 2026-07

Zone 6b Planting Calendar

Zone 6b

In zone 6b, the median last spring frost falls around Apr 10 and the first fall frost around Oct 27, giving roughly 199 frost-free days. Average annual minimum temperature is -5°F to 0°F. Every date in the table below is calculated from those two frost dates.

Comparable areas: Cincinnati, OH, Kansas City, MO, Hartford, CT. Ohio Valley, lower Midwest and interior southern New England. Interpolated between the verified Chicago 6a and St. Louis 7a anchors. Urban cores run a week or more later into fall than surrounding countryside.

What to plant and when in zone 6b

Sorted by when you start each crop. Dates are calculated from a median last frost of Apr 10 and a first frost of Oct 27.

Zone 6b planting calendar — 56 crops · last frost Apr 10 · first frost Oct 27
Crop Start indoors Plant outside Fall sowing Harvest from
Celery Jan 16 – Jan 30 Apr 24 – May 7 Aug 2 – Sep 1
Leek Jan 16 – Feb 13 Mar 13 – Mar 26 Jun 11 – Aug 10
Onion Jan 16 – Jan 30 Mar 20 – Apr 2 Jun 28 – Jul 18
Rosemary Jan 16 – Jan 30 Apr 24 – May 7 Jul 13 – Aug 2
Kale Jan 23 – Feb 13 Mar 13 – Mar 26 Aug 4 – Aug 17 May 2 – Jun 3
Broccoli Jan 30 – Feb 20 Mar 20 – Apr 2 Jul 28 – Aug 10 May 9 – Jun 18
Cabbage Jan 30 – Feb 20 Mar 20 – Apr 2 Jul 28 – Aug 10 May 19 – Jun 28
Pepper (sweet/bell) Jan 30 – Feb 27 May 1 – May 14 Jul 10 – Jul 25
Chives Jan 30 – Feb 13 Apr 10 – Apr 23 Jun 29 – Jul 9
Common Thyme Jan 30 – Feb 13 Apr 10 – Apr 23 Jun 9 – Jul 9
Greek Oregano Jan 30 – Feb 13 Apr 10 – Apr 23 Jun 29 – Jul 9
Cauliflower Feb 6 – Feb 27 Mar 27 – Apr 9 Jul 28 – Aug 10 May 16 – Jun 15
Eggplant Feb 13 – Feb 27 Apr 24 – May 7 Jun 18 – Jul 13
Sweet Potato Feb 13 – Feb 27 May 1 – May 14 Jul 30 – Aug 29
Basil Feb 13 – Feb 27 Apr 17 – Apr 30 Jun 23 – Jul 23
Garden Sage Feb 13 – Feb 27 Apr 10 – Apr 23 Jun 19 – Jun 29
Parsley Feb 13 – Feb 27 Apr 10 – Apr 23 Aug 18 – Aug 31 Jun 19 – Jun 29
Spearmint Feb 13 – Feb 27 Apr 10 – Apr 23 Jun 9 – Jul 9
Calendula / Pot Marigold Feb 13 – Feb 27 Mar 27 – Apr 9 Sep 1 – Sep 14 May 16 – May 26
French Marigold Feb 13 – Mar 13 Apr 17 – Apr 30 Jun 1 – Jun 16
Sweet Alyssum Feb 13 – Feb 27 Mar 27 – Apr 9 Sep 1 – Sep 14 May 8 – May 22
Tomato Feb 20 – Mar 6 Apr 17 – Apr 30 Jun 11 – Jul 16
Bok Choy Feb 27 – Mar 13 Mar 27 – Apr 9 Sep 1 – Sep 14 Apr 26 – May 26
Collard Greens Feb 27 – Mar 13 Mar 27 – Apr 9 Aug 4 – Aug 17 May 26 – Jun 15
Kohlrabi Feb 27 – Mar 13 Mar 20 – Apr 2 Aug 25 – Sep 7 May 16 – May 26
Lettuce Feb 27 – Mar 13 Mar 20 – Apr 2 Aug 18 – Aug 31 May 16 – Jun 5
Spinach Feb 27 – Mar 6 Mar 20 – Apr 2 Sep 8 – Sep 21 May 17 – May 28
Swiss Chard Feb 27 – Mar 13 Mar 27 – Apr 9 Sep 29 – Oct 12 May 6 – May 21
Pea Mar 6 – Mar 19 Aug 25 – Sep 7 Apr 30 – May 20
Rhubarb Mar 6 – Mar 19 Mar 5
Watermelon Mar 6 – Mar 27 Apr 24 – May 7 Jul 3 – Jul 28
Arugula Mar 13 – Mar 26 Sep 15 – Sep 28 Apr 12 – May 2
Asparagus Mar 13 – Mar 26 Mar 12
Cucumber Mar 13 – Mar 27 Apr 24 – May 7 Jun 13 – Jul 3
Pumpkin Mar 13 – Mar 20 Apr 24 – May 7 Jul 18 – Aug 22
Turnip Mar 13 – Mar 26 Aug 25 – Sep 7 Apr 22 – May 27
Nasturtium Mar 13 – Mar 20 Apr 17 – Apr 30 Jun 11 – Jun 21
Beet Mar 20 – Apr 2 Aug 18 – Aug 31 May 9 – May 29
Carrot Mar 20 – Apr 2 Aug 11 – Aug 24 May 19 – Jun 8
Potato Mar 20 – Apr 2 May 29 – Jul 18
Radish Mar 20 – Apr 2 Sep 15 – Sep 28 Apr 10 – May 4
Sunflower Mar 20 – Mar 27 Apr 17 – Apr 30 Jun 26 – Jul 26
Parsnip Mar 27 – Apr 9 Jul 15 – Aug 4
Winter Squash (Butternut) Mar 27 – Apr 3 Apr 24 – May 7 Jul 13 – Aug 2
Cantaloupe (Muskmelon) Mar 27 – Apr 3 Apr 24 – May 7 Jul 1 – Jul 18
Strawberry Mar 27 – Apr 9 Apr 24 – Apr 26
Dill Apr 3 – Apr 16 Aug 18 – Aug 31 May 13 – May 28
Bush bean Apr 10 – Apr 23 Aug 18 – Aug 31 May 30 – Jun 9
Pole bean Apr 10 – Apr 23 Jun 7 – Jun 12
Sweet corn Apr 10 – Apr 23 Jun 9 – Jul 19
Borage Apr 10 – Apr 23 May 30 – Jun 9
Cilantro / Coriander Apr 10 – Apr 23 Sep 1 – Sep 14 May 25 – Jun 19
Summer squash / zucchini Apr 17 – Apr 30 May 22 – Jun 11
Okra Apr 24 – May 7 Jun 23 – Jul 3
Brussels Sprouts Jun 19 – Jul 2 Jul 21 – Aug 3 Sep 12 – Oct 7
Garlic Oct 27 – Nov 9

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Planting dates are only useful if you remember them. Tell us your zone and we'll email you when it's time to start seeds indoors, when your last frost is close, and when the autumn sowing window opens — dated for your climate, not someone else's.

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One zone is not one climate. USDA hardiness zones are drawn from average winter minimum temperature and nothing else, so they do not determine frost dates. Two gardens in zone 6b can differ by two or three weeks depending on elevation, distance from water, and local topography. Treat this page as a starting schedule and adjust it to what your own garden has actually done. How these dates were derived →

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Zone 6b questions

When is the last frost in zone 6b?
The median last spring frost in zone 6b is around Apr 10. That is a midpoint, not a deadline — in half of years the last freeze lands later, so wait one to two weeks past it before setting out tender crops like tomatoes, peppers and basil.
How long is the growing season in zone 6b?
About 199 frost-free days, from roughly Apr 10 to Oct 27. That matters most for long-season crops: check a variety's days to maturity against that number before you buy seed.
What should I plant first in zone 6b?
Hardy crops go in well before your last frost — leek, onion, kale, broccoli tolerate frost and can be sown while the soil is still cold. Tender crops wait until after Apr 10.
Is zone 6b the same everywhere?
No. Hardiness zones are drawn from winter minimum temperature alone, so two gardens in the same zone can have frost dates weeks apart — Atlanta and Dallas–Fort Worth are both 8a and differ by about 20 frost-free days. Elevation, coastline, and even the bottom of a slope versus the top all shift these dates.