When to Plant Cabbage in New Hampshire
Published: April 24, 2026
New Hampshire gardeners in Zone 5b have a 28-week frost-free window for cabbage (April 7 to October 22). Cool-season crops like cabbage do well here because the short, cool summers match the plant's temperature preferences naturally. This guide gives exact dates for New Hampshire based on your local frost calendar.
Cabbage Planting Dates for New Hampshire
| Start seeds indoors | February 17–24 |
| Last frost (average) | April 7 |
| Transplant outdoors | March 17–27 |
| Expect first harvest | May 16 – June 25 |
| Fall crop start | July 30–August 9 |
| Fall harvest | September 28 |
| First fall frost (average) | October 22 |
Dates above assume Zone 5b, the most common zone in New Hampshire. Gardeners in cooler Nashua (Zone 5b) plant 1–2 weeks later; warmer Portsmouth (Zone 5a) can plant 1–2 weeks earlier.
⚠ Start cabbage indoors 6–8 weeks before last frost. Transplant 2–4 weeks before last frost. Very frost tolerant — withstands temperatures as low as 20°F. Also plant in late summer for fall harvest.
Growing Cabbage in New Hampshire's Climate
New Hampshire's cold Zone 5b climate is close to ideal for cabbage. The cool springs and moderate summers match the plant's natural temperature preferences, producing crisp, sweet, slow-bolting harvests that hot-climate gardeners cannot grow.
The fall cabbage crop in New Hampshire is often better than the spring crop. Plants mature as temperatures cool in September and October, concentrating sugars and tightening heads or roots. Light frost can improve flavor; hard frost signals harvest time.
Common cabbage pests to watch for in New Hampshire include Cabbage Worm and Cabbage Looper. The first line of defense is companion planting: Onion and Dill planted nearby discourage several of these pests by confusing host-plant identification or repelling adults before they can lay eggs. Weekly garden walks in the early morning catch problems when they're still manageable.
Cabbage Garden Calendar for New Hampshire
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | Start seeds indoors | Use grow lights; warm soil to 70–75°F for best germination |
| March | Transplant outdoors | Soil temp must be 45°F+; nighttime lows above 50°F |
| April | Harden off seedlings | Set seedlings outdoors 1–2 hours daily, increasing gradually |
| May ← | Watch for bolting | Harvest promptly; spring heat arrives quickly |
| June | — | Dormant season |
| July | Fall crop planting | Transplant or direct sow for fall harvest before frost |
| August | — | Dormant season |
| September | — | Dormant season |
| October | First frost approaches | Harvest remaining cabbage; cover plants on frost nights |
| November | — | Dormant season |
| December | — | Dormant season |
Cabbage Growing Tips for New Hampshire Gardeners
- •Space plants 18 inches apart — crowding reduces head size and promotes fungal disease.
- •Side-dress with nitrogen 3–4 weeks after transplanting to support rapid leaf formation.
- •New Hampshire's short growing season means start seeds indoors under grow lights — don't rely on windowsill light which produces leggy, weak seedlings that struggle outdoors.
- •Cover young transplants with floating row covers for the first 2–3 weeks outside. The 3–5°F of protection reduces frost damage risk and accelerates early growth.
- •Harvest when heads feel firm; leave the root ball in the ground and small secondary heads may form.
Companion Planting for Cabbage in New Hampshire
In New Hampshire's cold climate, planting cabbage with Onion and Dill helps deter pests and improve soil. Avoid planting near Tomato and Strawberry, which inhibit cabbage growth through root chemistry or shared pest pressure. See the full cabbage companion planting guide for the complete list.
Cabbage Planting Dates by City in New Hampshire
Top cities in New Hampshire — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant cabbage in New Hampshire?
In New Hampshire (Zone 5b), start cabbage seeds indoors around February 17–24 and transplant outdoors around March 17–27 — 3 weeks before the state's average last frost of April 7.
What is the last frost date in New Hampshire?
New Hampshire's average last frost date is April 7 in the state's most common Zone 5b. Frost dates vary by city — higher elevations and northern counties run 1 to 3 weeks later than the state average. See the city list below for city-level frost dates.
Can I grow cabbage year-round in New Hampshire?
cabbage is a cool-season crop in New Hampshire, with spring and fall windows. Summer heat bolts the plants before they can produce a harvestable crop. Succession planting every 2–3 weeks stretches the harvest window.
What cabbage varieties grow best in New Hampshire?
For New Hampshire's Zone 5b, consult a local nursery or extension office for cabbage variety recommendations.
When do I start cabbage seeds indoors in New Hampshire?
Start cabbage seeds indoors in New Hampshire around February 17–24, which is 7 weeks before the state's average last frost of April 7. Use grow lights and keep soil temperatures at 70–75°F for fastest germination.