What to plant in March in New Hampshire
In New Hampshire (NH), March sits about 8 weeks before the average last frost (May 13). The state averages 135 frost-free days a year (last frost May 13, first frost September 25; USDA zones 3b, 4a, 4b, 5a, 5b, 6a).
29 crops have a sowing or planting window this month - and 5 of those windows close during March.
Dates here come from New Hampshire frost dates (last frost May 13, first frost Sep 25). For one crop in detail, see when to plant onion, eggplant or bell pepper in New Hampshire.
New Hampshire: planting activity through the year
Last chance in March
Celeriac (start seeds indoors, by Mar 4) · Celery (start seeds indoors, by Mar 11) · Leek (start seeds indoors, by Mar 11) · Onion (start seeds indoors, by Mar 11) · Rosemary (start seeds indoors, by Mar 11)
Start seeds indoors in March (29)
Indoor sowings for transplants later. Six to eight weeks under lights is typical for tomatoes and peppers; onions and leeks need longer.
| Crop | What to do | Window | This month |
|---|---|---|---|
| Celeriac | Start seeds indoors | Feb 18 – Mar 4 | Last chance - ends Mar 4 |
| Celery | Start seeds indoors | Feb 25 – Mar 11 | Last chance - ends Mar 11 |
| Leek | Start seeds indoors | Feb 25 – Mar 11 | Last chance - ends Mar 11 |
| Onion | Start seeds indoors | Feb 25 – Mar 11 | Last chance - ends Mar 11 |
| Rosemary | Start seeds indoors | Feb 25 – Mar 11 | Last chance - ends Mar 11 |
| Eggplant | Start seeds indoors | Mar 4 – Mar 18 | Mar 4 – Mar 18 |
| Parsley | Start seeds indoors | Mar 4 – Mar 18 | Mar 4 – Mar 18 |
| Shallot | Start seeds indoors | Mar 4 – Mar 18 | Mar 4 – Mar 18 |
| Bell Pepper | Start seeds indoors | Mar 11 – Mar 25 | Mar 11 – Mar 25 |
| Chili Pepper | Start seeds indoors | Mar 11 – Mar 25 | Mar 11 – Mar 25 |
| Ginger | Start seeds indoors | Mar 11 – Mar 25 | Mar 11 – Mar 25 |
| Green Onion / Scallion | Start seeds indoors | Mar 11 – Mar 25 | Mar 11 – Mar 25 |
| Mint | Start seeds indoors | Mar 11 – Mar 25 | Mar 11 – Mar 25 |
| Oregano | Start seeds indoors | Mar 11 – Mar 25 | Mar 11 – Mar 25 |
| Sage | Start seeds indoors | Mar 11 – Mar 25 | Mar 11 – Mar 25 |
| Tarragon | Start seeds indoors | Mar 11 – Mar 25 | Mar 11 – Mar 25 |
| Thyme | Start seeds indoors | Mar 11 – Mar 25 | Mar 11 – Mar 25 |
| Turmeric | Start seeds indoors | Mar 11 – Mar 25 | Mar 11 – Mar 25 |
| Ground Cherry | Start seeds indoors | Mar 18 – Apr 1 | Opens Mar 18 |
| Lemon Balm | Start seeds indoors | Mar 18 – Apr 1 | Opens Mar 18 |
| Shiso (Perilla) | Start seeds indoors | Mar 18 – Apr 1 | Opens Mar 18 |
| Sweet Marjoram | Start seeds indoors | Mar 18 – Apr 1 | Opens Mar 18 |
| Tomatillo | Start seeds indoors | Mar 18 – Apr 1 | Opens Mar 18 |
| Tomato | Start seeds indoors | Mar 18 – Apr 1 | Opens Mar 18 |
| Broccoli | Start seeds indoors | Mar 25 – Apr 8 | Opens Mar 25 |
| Brussels Sprouts | Start seeds indoors | Mar 25 – Apr 8 | Opens Mar 25 |
| Cabbage | Start seeds indoors | Mar 25 – Apr 8 | Opens Mar 25 |
| Cauliflower | Start seeds indoors | Mar 25 – Apr 8 | Opens Mar 25 |
| Kale | Start seeds indoors | Mar 25 – Apr 8 | Opens Mar 25 |
Planting dates for popular crops in New Hampshire
Every crop has its own full-year dates for New Hampshire: indoor start, transplant or direct sowing, and harvest.
Seed-starting season: March garden jobs in New Hampshire
- Start 29 crops indoors this month, including celeriac, celery, leek, onion. Use a sterile mix and good light - see starting seeds indoors.
- 8 weeks until the average last frost (May 13). The seed-starting calculator works out each crop's exact sowing date from it.
- Keep seedlings from stretching: lights 2-3 inches above the leaves for 14-16 hours a day, and a fan or a daily brush of the hand across the tops.
- Prepare beds as soon as the soil crumbles instead of smearing when squeezed - working wet soil ruins its structure for the season.
USDA zone chart for New Hampshire
New Hampshire spans USDA zones 3b, 4a, 4b, 5a, 5b, 6a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average.
Questions gardeners ask
What vegetables can I plant in New Hampshire in March?
29 crops have a window in March: celeriac, celery, leek, onion, rosemary, eggplant, parsley, shallot, bell pepper, chili pepper and more. The tables above give the exact dates for each.
Is it too late to plant tomatoes in New Hampshire in March?
No - start seeds indoors runs Mar 18 – Apr 1 in New Hampshire.
Is it too late to plant lettuce in New Hampshire in March?
Not too late - it's actually a little early. In New Hampshire the next lettuce window opens around April 8: start seeds indoors.
When is the first frost in New Hampshire?
The statewide average first fall frost is around September 25 and the last spring frost around May 13. Your town can be a week or two either side - look yours up by ZIP code.
What should I start indoors in March in New Hampshire?
Celeriac (Feb 18 – Mar 4), Celery (Feb 25 – Mar 11), Leek (Feb 25 – Mar 11), Onion (Feb 25 – Mar 11), Rosemary (Feb 25 – Mar 11), Eggplant (Mar 4 – Mar 18), Parsley (Mar 4 – Mar 18), Shallot (Mar 4 – Mar 18), Bell Pepper (Mar 11 – Mar 25), Chili Pepper (Mar 11 – Mar 25), Ginger (Mar 11 – Mar 25), Green Onion / Scallion (Mar 11 – Mar 25), Mint (Mar 11 – Mar 25), Oregano (Mar 11 – Mar 25), Sage (Mar 11 – Mar 25), Tarragon (Mar 11 – Mar 25), Thyme (Mar 11 – Mar 25), Turmeric (Mar 11 – Mar 25), Ground Cherry (Mar 18 – Apr 1), Lemon Balm (Mar 18 – Apr 1), Shiso (Perilla) (Mar 18 – Apr 1), Sweet Marjoram (Mar 18 – Apr 1), Tomatillo (Mar 18 – Apr 1), Tomato (Mar 18 – Apr 1), Broccoli (Mar 25 – Apr 8), Brussels Sprouts (Mar 25 – Apr 8), Cabbage (Mar 25 – Apr 8), Cauliflower (Mar 25 – Apr 8), Kale (Mar 25 – Apr 8).
What to plant in March in other states
Dates are computed from New Hampshire’s statewide average frost dates (from NOAA/NCEI climate normals) and each crop’s timing in our crop database. Your garden may be a week or two either side - for dates tuned to your ZIP code, use the planting calendar.