May is the most exciting and the most dangerous month in a cold-zone garden. The soil is workable, the days are long, and everything wants to go outside at once — but the average last frost is still in May or early June, and one cold night can undo weeks of indoor growing. May is a month of two halves: hardy crops go out early, tender crops go out only at the very end, and only if the forecast allows.
The way to think about May is in sequence, not all at once.
Zone 2 in May: the frost window
Zone 2 is one of the coldest USDA zones, with winter lows of -50 to -40°F. The average last spring frost falls June 1–15 and the average first autumn frost falls August 15–September 1, which leaves roughly eleven to thirteen weeks between the average last spring frost and the average first autumn frost. Everything here runs on a very late timetable: tender crops go out only in June, and the whole outdoor season is a sprint. Those dates are USDA zone averages from the USDA Plant Hardiness Zone Map and NOAA frost records — they are ranges, not exact dates for any one garden, and they vary by microclimate, elevation and year, so check your local extension service before you plant tender crops outside. Our frost date calculator gives you the averages for your zone, and the planting calendar hub lists every zone and month.
Your May task list
- Sow hardy crops early in the month and tender crops only at the end, after the last frost average.
- Harden off and transplant brassicas, onions and leeks; keep row cover ready.
- Plant seed potatoes if not done in April — they take 70–120 days, so May is the last sensible planting for a good harvest.
- Water new sowings gently and consistently — seeds germinating in 7–14 days need moist soil, not a soaking.
- Mulch beds once plants are established to hold moisture and suppress weeds.
- Watch for slugs and cutworms on young seedlings, especially after damp weather.
What to start indoors in May
- Beans and squash (for transplanting) — Beans take 50–65 days and squash 45–55 days, and both are tender. Starting them indoors in May gives them a head start without risking them outside too early.
- Succession lettuce and herbs — Sow a second batch of lettuce indoors or directly outside in May so salads keep coming after the first sowing matures.
- Flowers for pollinators — Marigolds and other companion flowers started indoors now will be ready to plant beside tomatoes and squash when those go out.
Give seedlings strong light close above them, keep the soil moist but not soggy, and label every tray with the crop and sowing date.
What to direct-sow outdoors in May
Direct sow in May: peas, spinach, lettuce, radishes, carrots, beets, turnips (40–60 days, hardy), and potatoes if you have not already planted them. Toward the end of the month, once the last frost average has passed and the soil is warm, you can also direct-sow beans, zucchini and cucumbers — but only if the forecast is settled. In a short season, a bean sown a week late but into warm soil will often overtake one sown early into cold soil.
What to transplant and harvest in May
Transplant brassicas, onions, leeks, kale and chard throughout May, hardened off and with row cover on cold nights. Tender transplants — tomatoes, peppers, eggplant, cucumbers, zucchini and basil — go out only in late May, after the average last frost and only when nights are mild. Harden them off over a week first, and keep fleece or buckets handy for a surprise cold night.
The first real harvests arrive in May: radishes sown in April are ready in 25–40 days, and early lettuce and spinach can be cut leaf by leaf. Asparagus, if you have an established bed, is cut through spring — it takes years to establish (730–1,095 days to maturity from seed), so a May harvest is the reward for patience, not a first-year crop. Snip chives and other perennial herbs as they regrow.
Frost protection in May
May frost protection is active work: check the forecast every evening, and cover tender transplants with fleece, cloches or upturned buckets on any night that threatens frost. Row cover can protect hardy crops by a few degrees. Watering the soil before a frosty night can help, because moist soil holds heat better than dry soil — but do not soak seedlings. Your frost dates are averages, so a late frost after the average date is entirely possible; check your local extension service.
May planting data — Zone 2
| Crop | Germination | Days to maturity | Spacing | Soil pH | Cold tolerance |
|---|---|---|---|---|---|
| Radishes | 4–7 days | 25–40 days | 2–3 in | 6.0–7.0 | hardy |
| Lettuce | 7–10 days | 45–60 days | 8–12 in | 6.0–7.0 | hardy |
| Peas | 7–14 days | 60–70 days | 2–3 in | 6.0–7.5 | hardy |
| Potatoes | 14–28 days | 70–120 days | 12 in | 5.0–6.0 | frost-tolerant |
| Green beans | 7–10 days | 50–65 days | 4–6 in | 6.0–7.0 | tender |
Frequently asked questions
What can I plant in May?
Early May: hardy crops such as peas, lettuce, spinach, carrots, beets and potatoes. Late May, after the average last frost: tender crops such as tomatoes, peppers, beans, squash and cucumbers — but only if the forecast is settled.
Is it safe to plant tomatoes outside in May?
Only late in the month, after your average last frost, and only after hardening off. Tomatoes are tender and take 60–85 days to maturity; a frost will kill them, so keep fleece handy for the first weeks outside.
Why are my peas not germinating?
Peas germinate in 7–14 days in moist, cool soil, but they rot in cold, waterlogged ground. If the soil is sodden, wait for it to drain, or sow into a raised bed or under cover.
When is the last frost in my zone?
In Zone 2, the average last spring frost falls June 1–15 and the average first autumn frost falls August 15–September 1. Frost dates here are zone averages, not exact dates for any one place, and they vary by microclimate, elevation and year — check your local extension service before planting tender crops outside.
May is the month the garden becomes a garden: hardy crops in, tender crops hardening off, and the first radishes on the plate. Plant in sequence, cover on cold nights, and the short season will reward you. Browse the planting calendar hub for every month in your zone, see last month, or look ahead to next month, and see how the same month looks in a milder zone in the Zone 7 January guide.