Maine's growing season runs roughly 120 days in the south (Portland area, last frost ~May 15, first frost ~October 1) and shrinks to under 100 days in the north, where June frosts are not unusual. That hard ceiling rules out most warm-season crops entirely and makes every planting date consequential. The question isn't whether your crop can handle cold โ it's whether it can complete its life cycle before the window slams shut.
The good news is that cool-season crops, which struggle through summer heat elsewhere, hit their prime in Maine's mild summers. Consistent temps in the 60sยฐF produce sweeter roots, tighter brassica heads, and lettuces that don't bolt for weeks. Crops that need a cold vernalization period โ garlic, overwintered onions โ find Maine's winters ideal rather than threatening. The state's climate is a liability for warm-season gardeners and an asset for cool-season ones.
Success in Maine hinges on three tactics: starting brassicas and onions indoors in late March to early April to bank weeks before transplant; direct-sowing fast crops like radishes, spinach, and peas as soon as soil is workable (often late April, even with frost in the forecast); and planning a second sowing of many crops in late July or August for a fall harvest that frost actually improves.
At a glance
| Crop | Type | Days to harvest | Sun | Heat | Frost | Level |
|---|---|---|---|---|---|---|
| Pea | Cool | 55โ70 days | Full | โ | โ | Easy |
| Broccoli | Cool | 60โ90 days | Full | โ | โ | Moderate |
| Cabbage | Cool | 60โ100 days | Full | โ | โ | Moderate |
| Cauliflower | Cool | 60โ100 days | Full | โ | โ | Hard |
| Kale | Cool | 50โ65 days | Full | โ | โ | Easy |
| Lettuce | Cool | 30โ60 days | Part | โ | โ | Easy |
| Spinach | Cool | 35โ50 days | Part | โ | โ | Easy |
| Swiss chard | Cool | 50โ60 days | Full | โ | โ | Easy |
| Carrot | Cool | 60โ80 days | Full | โ | โ | Moderate |
| Beet | Cool | 50โ70 days | Full | โ | โ | Easy |
| Radish | Cool | 25โ35 days | Part | โ | โ | Easy |
| Onion | Cool | 90โ120 days | Full | โ | โ | Moderate |
| Garlic | Cool | 240โ270 days | Full | โ | โ | Easy |
| Strawberry | Cool | 90โ110 days | Full | โ | โ | Moderate |
Why each one works
Pea
Cool-season 55โ70 daysPeas are the first crop in the ground and the first on the table in Maine. They germinate in soil as cold as 40ยฐF and can handle frost down to the mid-20sยฐF, making late April direct-sowing not only possible but optimal โ warmer soil triggers bolting, not better growth. The 55โ70-day window fits even northern Maine's tightest seasons. Direct-sow Sugar Snap or 'Lincoln' shell peas in late April and plant a second succession in mid-August for fall pods before hard freeze.
Full pea growing guide โBroccoli
Cool-season 60โ90 daysBroccoli thrives in exactly the cool, moist conditions Maine provides through summer, and a light frost after heading actually tightens the florets and sweetens the flavor. Starting transplants indoors in late March and setting them out in mid-May gives the crop enough runway to head before summer's warmest weeks. Run two rounds: transplant the first in May, then direct-sow or transplant a second round in mid-July for heads that mature in September's reliable cool.
Full broccoli growing guide โCabbage
Cool-season 60โ100 daysCabbage is one of Maine's best storage crops โ started indoors in early April, transplanted after last frost, and left to size up through the mild summer, it heads reliably within the season and improves markedly after October frosts sweeten the leaves. Storage varieties like 'Danish Ballhead' or 'Murdoc' hold in a cool cellar for months, extending the harvest well into winter. Plant transplants 18 inches apart and side-dress with nitrogen at cupping stage for maximum head size.
Full cabbage growing guide โCauliflower
Cool-season 60โ100 daysCauliflower is the hardest crop on this list precisely because it demands consistent soil moisture and cool temps during head development โ any heat spike above 75ยฐF triggers buttoning or loose curds. Maine's cool summers are genuinely ideal for this, which is why cauliflower succeeds here when it fails in warmer climates. Start indoors in mid-March, transplant mid-May, and blanch heads by securing outer leaves over curds once they reach golf-ball size to prevent yellowing.
Full cauliflower growing guide โKale
Cool-season 50โ65 daysKale is arguably the most foolproof vegetable for Maine: it tolerates frost down to 20ยฐF, actually converts starches to sugars after a hard freeze, and can be harvested from June through December with no protection. It can be direct-sown or transplanted, and it keeps producing as outer leaves are harvested. Lacinato (dinosaur) kale and 'Red Russian' are the hardiest varieties; sow in mid-May and expect to be harvesting into November even without row cover.
Full kale growing guide โLettuce
Cool-season 30โ60 daysLettuce's 30โ60-day maturity is a gift in Maine โ you can sow it from late April through late August and get multiple successions without fear of missing the window. It germinates readily in cool soil and, with the right variety selection, holds in the garden without bolting through Maine's mild July. Sow a short row every 2โ3 weeks and favor heat-tolerant varieties like 'Jericho' or 'Nevada' for the brief mid-summer period; switch back to butter-heads and oakleafs in August for fall harvests.
Full lettuce growing guide โSpinach
Cool-season 35โ50 daysSpinach can go into the ground in late April โ even earlier under row cover โ and matures before summer heat triggers bolting, making it one of the few crops that genuinely benefits from Maine's slow spring warm-up. A second sowing in late August exploits cooling fall temperatures and produces the sweetest leaves of the year. 'Bloomsdale Long Standing' is slower to bolt than most varieties, buying extra weeks of harvest; for fall, 'Tyee' holds well into hard frost.
Full spinach growing guide โSwiss chard
Cool-season 50โ60 daysSwiss chard is uniquely valuable in Maine because it bridges the whole season: it tolerates the cold snaps of early June and the brief heat of July with equal composure, and it keeps producing until a hard freeze in October or November. Direct-sow after last frost (mid-May) and harvest outer stalks continuously rather than cutting the whole plant. 'Fordhook Giant' is the most reliable all-purpose variety; 'Bright Lights' mixes perform well and hold up to frost without losing quality.
Full swiss chard growing guide โCarrot
Cool-season 60โ80 daysCarrots direct-sown in early May mature in 60โ80 days โ well within the Maine season โ and can be left in the ground past first frost, where cold temperatures convert starches to sugars and dramatically improve flavor. They actually germinate better in Maine's naturally cool, moisture-retentive soils than in sandy warm-climate beds. 'Napoli' and 'Bolero' are consistent performers; mulch rows heavily in late September and you can harvest into November or even December with roots still firm in the ground.
Full carrot growing guide โBeet
Cool-season 50โ70 daysBeets tolerate frost, mature in 50โ70 days, and deliver two harvests in one โ the greens from thinning can be eaten early, and the roots harvested once they reach golf-ball to tennis-ball size. A first sowing in early May and a second in late July gives a continuous supply through October. 'Detroit Dark Red' is the most reliable for storage; 'Chioggia' matures slightly faster and handles cool soil germination well.
Full beet growing guide โRadish
Cool-season 25โ35 daysRadishes are Maine's fastest crop at 25โ35 days, which means you can sow the first ones in late April and get multiple successions from the same bed before fall. They're also useful as row markers for slow-germinating carrots โ radishes emerge in a week, mark the row, and are pulled before carrots need the space. Sow a short row every two weeks from late April through early September; avoid midsummer sowings in July, when heat pushes them to bolt before sizing up.
Full radish growing guide โOnion
Cool-season 90โ120 daysOnions have Maine's longest in-ground season of any annual crop here at 90โ120 days, which means they must be started from seed indoors in late February โ not April โ or planted from sets in early May. Critically, Maine's latitude requires long-day varieties (those that bulb when day length exceeds 14 hours); short- or intermediate-day types will fail to size up. 'Copra', 'Patterson', and 'Cortland' are proven long-day varieties for the Northeast; cure bulbs in a warm, airy location for 3โ4 weeks before storage.
Full onion growing guide โGarlic
Cool-season 240โ270 daysGarlic is Maine's most winter-adapted crop: planted in mid-October, it overwinters under the snow, vernalizes in the cold (which is required for bulb development), and is harvested in late July โ completely sidestepping the short-season problem by using months when the garden would otherwise sit empty. Hardneck varieties are essential in cold climates; 'Music', 'Chesnok Red', and 'German Extra Hardy' all overwinter reliably in zone 5. Plant cloves 2 inches deep and mulch with 4 inches of straw before the ground freezes hard.
Full garlic growing guide โStrawberry
Cool-season 90โ110 daysJune-bearing strawberries align almost perfectly with Maine's summer, producing a concentrated crop in late June to mid-July when conditions are ideal: mild temperatures, good soil moisture, and long days. Hardy varieties handle Maine's winters without consistent mulching failure, though a straw mulch applied after the ground freezes prevents the freeze-thaw heaving that kills crowns. Plant 'Annapolis' or 'Cavendish' โ both bred for northeastern conditions โ in early May, suppress runners the first year, and expect a full crop in year two.
Full strawberry growing guide โFrequently asked questions
When should I start vegetable seeds indoors in Maine?
Work backward from your last frost date โ May 15 for most of southern Maine, June 1 for the north. Broccoli, cabbage, and cauliflower need 6โ8 weeks indoors, so start them in late March to early April. Onions need 10โ12 weeks, meaning late February starts are necessary. Lettuce and kale can be started 4 weeks before transplant or direct-sown as soon as the soil is workable.
Can I extend Maine's growing season, and by how much?
Row cover (floating fabric) adds 4โ6ยฐF of frost protection and can push both ends of the season by 3โ4 weeks โ enough to start transplanting brassicas in early May and harvest greens into November. Cold frames and low tunnels extend that further, keeping spinach and kale productive through December in southern Maine. The investment pays off most on high-value, quick-maturing crops like lettuce, spinach, and radishes where extra weeks mean extra successions.
Which crops should I avoid planting in Maine?
Warm-season crops with long days-to-maturity are the main risk: standard pumpkins (100+ days), sweet potatoes, melons, and peppers routinely fail to mature before first frost in all but the warmest southern Maine microclimates. If you grow tomatoes, stick to early varieties like 'Stupice' or 'Siletz' (under 70 days) and start them indoors in late March. Eggplant and okra are generally not worth the effort in zone 5 without a greenhouse.
Do raised beds make a meaningful difference in Maine?
Yes โ raised beds warm 2โ3 weeks faster in spring than in-ground beds because the soil mass is exposed on the sides and drains quickly after snowmelt. In Maine, where every week of the growing season matters, that head start is significant. Raised beds also prevent the waterlogging that cool, heavy spring soils cause, which kills brassica transplants and rots direct-sown seeds. Fill with a mix that includes compost to hold moisture through dry July stretches without becoming compacted.