USDA Zone 6b Planting Calendar (2026)
Zone 6b (-5 to 0°F) has an average last spring frost on Apr 15 and first fall frost on Oct 20 — about 188 growing days. Typical areas: Washington DC, Lexington KY.
How to use the zone 6b planting calendar
Every planting date on this page is calculated from zone 6b's average frost dates. Because your last spring frost lands around Apr 15 and your first fall frost around Oct 20, you have roughly 188 frost-free days to work with — a moderate growing season. The table below lists, for each of 20 common vegetables, when to start seeds indoors, when to sow or transplant outdoors, and when you can expect your first harvest.
Frost dates are averages, not guarantees. In a cold year the last frost can arrive 1-2 weeks later, so keep row covers handy for tender seedlings in Apr. Click any vegetable name to open a detailed zone 6b guide with spacing, companions, container tips and troubleshooting.
Cool-season crops for zone 6b
These tolerate light frost and go out first, 2-4 weeks before your Apr 15 last frost, and again in late summer for a fall crop: lettuce, carrot, broccoli, spinach, kale, onion, garlic, potato, peas, radish, beet, cabbage, cauliflower.
Warm-season crops for zone 6b
These need warm soil and frost-free weather, so plant them after Apr 15: tomato, pepper, cucumber, corn, bush beans, summer squash, zucchini. In a moderate season, start the slowest ones indoors to be sure they ripen before Oct.
| Vegetable | Start Indoors | Sow / Transplant | Harvest From |
|---|---|---|---|
| Beet | — | Mar 18 | May 12 |
| 🥦 Broccoli | Mar 11 | Apr 1 | Jun 5 |
| 🫘 Bush Beans | — | Apr 22 | Jun 16 |
| 🥬 Cabbage | Mar 4 | Apr 1 | Jun 20 |
| 🥕 Carrot | — | Mar 25 | Jun 3 |
| 🥦 Cauliflower | Mar 4 | Apr 1 | Jun 15 |
| 🌽 Corn | — | Apr 29 | Jul 18 |
| 🥒 Cucumber | Mar 25 | Apr 29 | Jun 23 |
| 🧄 Garlic | — | Sep 30 | May 28 |
| 🥬 Kale | Mar 11 | Mar 25 | May 19 |
| 🥬 Lettuce | Mar 18 | Mar 25 | May 9 |
| 🧅 Onion | Feb 4 | Mar 18 | Jun 26 |
| 🟢 Peas | — | Mar 4 | May 3 |
| 🫑 Pepper | Feb 18 | Apr 29 | Jul 8 |
| 🥔 Potato | — | Apr 1 | Jun 30 |
| 🌶️ Radish | — | Mar 18 | Apr 15 |
| 🍃 Spinach | — | Mar 11 | Apr 20 |
| 🎃 Summer Squash | Mar 25 | Apr 22 | Jun 11 |
| 🍅 Tomato | Mar 4 | Apr 22 | Jul 6 |
| 🥒 Zucchini | Mar 25 | Apr 22 | Jun 11 |
Spring, summer and fall planting in zone 6b
Spring (Apr): As soon as the soil can be worked, direct sow hardy cool-season crops and set out frost-tolerant transplants. This is your window for peas, lettuce, spinach and the brassicas before summer heat arrives.
Early summer (after Apr 15): Once frost danger passes and soil warms past 60°F, transplant tomatoes, peppers and squash and direct sow beans and cucumbers. This is the heart of the zone 6b growing season.
Late summer to fall (before Oct 20):Sow a second round of quick cool-season crops for a fall harvest. Count back each crop's days-to-harvest from Oct 20 to find the latest safe sowing date, and use row covers to stretch the season a few extra weeks.
Zone 6b planting FAQ
What planting zone is Washington DC?
Areas like Washington DC, Lexington KY fall in USDA hardiness zone 6b, defined by an average annual minimum temperature of -5 to 0°F. Your average last spring frost is around Apr 15 and your first fall frost around Oct 20.
When is the last frost in zone 6b?
The average last spring frost in zone 6b is around Apr 15. Wait until after this date before transplanting warm-season crops like tomatoes, peppers and squash. Cool-season crops can go out 2-4 weeks earlier because they tolerate light frost.
How long is the growing season in zone 6b?
Zone 6b has roughly 188 frost-free days between the last spring frost (Apr 15) and first fall frost (Oct 20). That is a moderate season — enough time for most vegetables plus some succession planting.
What vegetables grow best in zone 6b?
Reliable choices for zone 6b include cool-season crops such as lettuce, carrot, broccoli, spinach planted in early spring, and warm-season crops such as tomato, pepper, cucumber, corn planted after the last frost. See the full table below for exact dates.
Can I grow a fall garden in zone 6b?
Yes. With a first frost around Oct 20, you can plant a second round of quick cool-season crops in mid to late summer. Count back the days-to-harvest from Oct 20 to find your fall planting date.
When should I start seeds indoors in zone 6b?
Most warm-season seedlings are started indoors 6-8 weeks before the last frost — that means roughly Apr for zone 6b. Tomatoes, peppers and eggplant benefit most from an indoor head start in this zone.