When to Plant in Anchorage, AK

Anchorage gardeners work within a compact, clearly defined season: the climatological median last spring frost is May 30 and the median first fall frost is September 10, yielding only 108 frost-free days. This short window governs cultivar choice, sowing calendars and harvest timing. Long daylight hours in late June and July accelerate vegetative growth, but accumulated warmth remains limited, and cool nights slow fruit maturation for heat-loving crops. Success here depends on selecting quick-maturing varieties, using season-extension tactics like row covers, cloches and cold frames, careful succession planting, and preparing soils to warm quickly with raised beds or dark mulches.

The microclimate in Anchorage is subarctic continental: long summer daylight combined with cool nights, low cumulative heat (limited growing degree days) and a short frost-free period. Crops that excel are cool-season and quick to mature — for example, kale thrives with cool nights and resists light frosts, garden peas benefit from cool, long-day development and produce sweet pods, and root vegetables such as carrots and beets tolerate cool soils and mature reliably within the shorter season. Crops that struggle include sweet corn and many long-season indeterminate tomatoes because they require sustained warmth, more growing degree days for kernel filling or fruit ripening, and consistent warm nights for proper maturation — conditions that the short Anchorage season and cool nights often do not provide.

What to plant now in Anchorage

Spring: Direct-sow peas, kale, spinach and radishes into garden as soil warms; sow brassicas earlier for transplanting. Time outdoor sowing around the frost transition after May 30; use row covers for protection.
Summer: Plant heat-tolerant transplants like potatoes, beans and cucumbers after May 30, when frost risk passes; mulch and water to conserve warmth and extend the short growing season before September 10.
Fall: Sow cover crops, transplant garlic, and finish root harvests well before the median first fall frost on September 10; plan tender crop cleanup and apply mulch to protect perennials from subarctic continental winter stress.
Winter: Order seeds, plan beds, and start cold-hardy indoor sowing under lights for brassicas and salad greens six to eight weeks before May 30 so seedlings are ready to harden off after the frost.

In Anchorage (103 frost-free days, a short season), 29 of 56 planner crops fit outright, 15 get two plantings, 6 need an indoor start, 5 don't reliably mature, 1 crop is perennial.

Month by month in Anchorage

Month	What to do
January	January: Use long winter nights for planning, ordering seeds and mapping beds. Review crop rotations, select cold‑tolerant varieties for subarctic continental conditions, and check storage for seed viability before early spring starts.
February	February: Start brassica and herb seeds indoors under lights; plan timing so seedlings can be hardened and transplanted relative to the May 30 last frost. Repair tools and prepare cloches and row cover supplies.
March	March: Begin seed starting for tomatoes, peppers and long-season transplants well in advance to be ready after May 24. Monitor soil warming; prepare raised beds and cold frames for early garden access.
April	April: Harden off brassicas and cold‑tolerant seedlings in protected spots; direct sow early carrots and peas as soil permits. Anticipate the frost transition toward May 30 and keep row covers ready for nights.
May	May: Watch the median last spring frost on May 30 closely. Hold off transplanting tender tomatoes and peppers until after that frost transition; stagger plantings and keep frost protection for unexpected cold snaps.
June	June: After the frost transition around late May, crops grow quickly during long daylight. Plant successive lettuce and root crops, monitor soil moisture, and side-dress heavy feeders like cabbage and brassicas for vigorous growth.
July	July: Peak production for peas, salad greens, and early root crops occurs; harvest frequently to encourage production. Shade tender vegetables during brief heat spells and maintain even watering in subarctic continental soils.
August	August: Begin planning fall sowings and second plantings of quick crops. Watch daylength decline and start bolting management; prepare to harvest summer crops early enough to finish before the median first fall frost on September 10.
September	September: Expect the median first fall frost on September 10 and plan final harvests accordingly. Bring tender pots indoors, protect late transplants with covers, and finish planting garlic and cover crops before frost.
October	October: Clean up spent tomato and pepper plants promptly after frost; mulch berries and perennials. Use this month to repair beds, apply compost, and ensure garlic plantings are insulated before deep subarctic continental freeze.
November	November: Finish garden winterizing tasks: drain irrigation, store tools, and protect crowns of perennial herbs. Record notes about yields and varieties to refine next year’s selections in the constrained subarctic continental growing season.
December	December: Rest, evaluate last season and plan seed lists. Maintain greenhouse and cold frame equipment; order hardy cultivars suited for the short 108 frost-free days and schedule sowing calendars around May 30.

Frost dates for Anchorage ZIP codes

ZIP	Last spring frost (50%)	First fall frost (50%)	Zone
99504	May 26	September 10	5a
99515	May 30	September 10	5a
99516	May 26	September 10	5b

FAQ

When is the last frost in Anchorage?

The median last spring frost in Anchorage is May 30. Use May 30 as your baseline for timing tender transplants outdoors, but always check local nighttime temperatures and microclimate variations, and be ready to protect young plants with covers.

What vegetables grow best in Anchorage?

Vegetables that perform best are cool-season, quick-maturing and cold-tolerant: kale, spinach, garden peas, radishes, carrots, beets and early potatoes. Brassicas (cabbage, broccoli) also excel because they tolerate cool nights and mature reliably within the shorter subarctic continental season.

When should I plant tomatoes in Anchorage?

Start tomato seeds indoors six to eight weeks before May 30 so transplants are ready to harden off at outdoor temperatures. Transplant tomatoes only after the May 30 frost transition, choose early-maturing or determinate varieties, and use cloches or a sheltered greenhouse to add heat and protect from cool nights.

Can I garden year-round in Anchorage?

Outdoor cropping year-round is not feasible because subarctic continental winters bring deep freezes and a short 108-day frost-free period. However, year-round production is possible with heated greenhouses, insulated cold frames or indoor microgreen and herb setups; unheated cold frames can overwinter very hardy greens and allow early spring access.

How does Plan My Garden help Anchorage gardeners?

Plan My Garden provides date-aware guidance keyed to your median frost dates—we center sowing and transplant recommendations around September 10 and the September 10 fall threshold, highlight your 108 frost-free-day window, and offer cultivar suggestions, season-extension tactics, and scheduling tools to optimize sowing dates, hardening-off, succession planting and harvest timing for the subarctic continental microclimate.