Every February, the seed catalogs arrive and the planning begins. And every February, someone asks the same question: when do I start my tomatoes? The answer depends entirely on where in New England you're growing — and "New England" covers a lot of ground, and more than a few hardiness zones.
Know Your Zone — Then Go Further
This guide covers Zone 4b through Zone 7a, which spans the full range of New England growing conditions — from the frost pockets of northern Maine and the White Mountains down to the coastal lowlands of Rhode Island and Connecticut.
- Zone 4b–5a — Northern Vermont, northern New Hampshire, northern Maine, higher elevations. Last frost: late May to early June. First fall frost: mid-September.
- Zone 5b–6a — Central Vermont, central New Hampshire, western Massachusetts, central Maine. Last frost: mid to late May. First fall frost: late September to early October.
- Zone 6b–7a — Southern Connecticut, Rhode Island, the Boston metro, Cape Cod, coastal lowlands. Last frost: late April to early May. First fall frost: mid to late October.
USDA zones tell you about average minimum winter temperatures — useful for perennials, but not the whole story for vegetables. What actually governs your season is your last spring frost date and your first fall frost date. Find yours at the Old Farmer's Almanac by zip code. Once you have those two dates, everything else is math.
January — Rest, But Plan
Nothing goes in the ground. Nothing goes under lights yet either, unless you're starting onions — they need a full 10 to 12 weeks and benefit from the earliest possible start. Order your seeds now if you haven't. The best varieties sell out by March.
February — Onions and the First Trays
Start onions from seed indoors in early February regardless of your zone. They're slow, they're fussy, and they need more light than a south-facing window can reliably provide in February. A grow light 2 to 3 inches above the tray makes a real difference.
Celery and celeriac can also go in late February. Both need 10 to 12 weeks and neither tolerates frost well — so an early indoor start is the only way to get a full harvest in the shorter-season zones.
March — Peppers, Then Tomatoes
Peppers go in early to mid March across most zones — 10 to 12 weeks before your last frost date. They need bottom heat to germinate reliably. A seedling heat mat is worth the investment. Without consistent soil warmth, germination rates drop significantly.
Tomatoes follow based on your zone:
- Zone 6b–7a — Start tomatoes in early to mid March (7 to 8 weeks out)
- Zone 5b–6a — Start in mid to late March (6 to 7 weeks out)
- Zone 4b–5a — Start in late March to early April (6 weeks out from a late May/early June transplant date)
This is where most people start too early. A leggy, root-bound tomato transplanted in June will catch up to a well-grown 6-week seedling within two weeks. Bigger is not better.
April — The Busiest Month
April is when the seed-starting calendar stacks up fast. Timing by zone:
- Brassicas (broccoli, cabbage, kale starts) — 4 to 6 weeks before your last frost date
- Basil — 4 to 6 weeks before last frost, but keep them warm; basil hates cold roots
- Squash and cucumbers — 3 to 4 weeks before last frost, no earlier; they get rootbound fast
- Direct sow outdoors — peas, spinach, lettuce, radishes, and carrots can go in the ground as soon as the soil is workable in Zones 5b and warmer. Zone 4b and 5a growers should wait until mid to late April at the earliest.
Cool-season crops don't just tolerate cold — they prefer it. Lettuce started in 40-degree soil will outperform lettuce started in 70-degree soil once summer heat arrives.
May — Hardening Off and the Last Push
May is transition month. Everything that's been growing under lights needs to harden off before it goes in the ground — a week of progressively longer outdoor exposure, starting in shade, working up to full sun. Skip this step and you'll lose leaves to sunscald within 48 hours.
Transplant timing by zone:
- Zone 6b–7a — Tomatoes, peppers, and basil can go out in early to mid May after hardening
- Zone 5b–6a — Memorial Day weekend is the traditional and reliable date for most of inland New England
- Zone 4b–5a — Hold until early June. One 28-degree night ends your tomatoes. The calendar is a guideline. The thermometer is the rule.
June — Direct Sow Everything Else
Once your last frost has passed, the direct-sow window opens wide. Beans, corn, basil transplants, melons, and winter squash — everything that needs warm soil can go in now.
Winter squash variety selection matters more as you move north:
- Zone 6b–7a — Up to 100-day varieties are viable
- Zone 5b–6a — Stick to 85 days or fewer; Butternut and Delicata are reliable choices
- Zone 4b–5a — Target 75 to 80 days maximum; Acorn and early Butternut varieties are your best bet
Succession plant lettuce and radishes every two weeks through June for a continuous harvest before summer heat shuts them down.
The Numbers That Actually Matter
Your last spring frost date and your first fall frost date define your season. That window runs roughly 100 to 110 days in Zone 4b, 130 to 145 days in Zone 5b–6a, and 155 to 170 days in Zone 6b–7a. Everything else — what to grow, when to start it, which varieties to choose — follows from knowing exactly where you fall in that range.
Get the dates. Do the math. Start on time, not early.
Whatever you're growing this season — grow it well.