March in Zone 3
March in Zone 3: indoor seed starting continues; ground thaws late in the month. Start squash and cucumbers indoors.
Quick answer · Updated July 2026
In March, Zone 3 gardeners can plant Cucumbers, Zucchini, Summer squash, Melons, Broccoli, Cabbage, Cauliflower, and Kale. Zone 3's last frost is around Mid May – early June and first frost around Early September – early October — the full task list below has exact timing for each crop.
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- Min Winter Temp
- -40 to -30 °F / -40 to -34 °C
- Last Spring Frost
- Mid May – early June
- First Fall Frost
- Early September – early October
- Growing Season
- 100–130 days
- Annual Rainfall
- 15–35 in
Gardening in March in Zone 3
March is the depth of winter in Zone 3. With the last spring frost not due until around Mid May – early June, the garden is dormant and the real work is planning — ordering seeds, sketching beds, and starting only the longest-season crops indoors.
The planting focus in Zone 3 this month is Cucumbers, Zucchini, Summer squash, Melons, Broccoli, and Cabbage — see the task cards below for exactly how and when to sow each in your conditions.
About March in the garden
March is the month of transition. Cold-zone gardeners begin direct sowing the hardiest crops; warm-zone gardeners are in full spring planting mode. Spring equinox brings equal day and night, and soil temperatures begin to rise significantly.
Direct sowing peas, spinach, and lettuce in cold zones; transplanting tomatoes and peppers in Zone 9–10; pruning and dividing perennials; preparing beds.
- Season
- spring
- Temperature trend
- Rapidly warming in most regions; significant week-to-week temperature changes.
- Daylight
- Spring equinox (around March 20); days and nights are equal length, then days lengthen rapidly.
- Zone 3 last frost
- Mid May – early June
- Zone 3 first frost
- Early September – early October
8
Sow indoors
0
Sow outdoors
0
Transplant
0
Harvest
2
Maintenance
🌱 Sow indoors
Start cucumbers, squash, and melons indoors (4 weeks before last frost)
Sow 2 seeds per cell ½ inch deep; thin to one seedling; transplant carefully to avoid root disturbance.
Sow 1 inch deep, 1 seed per large cell; transplant at true-leaf stage — roots are sensitive.
Sow 1 inch deep in individual pots; direct sow is preferred once soil hits 60°F.
Sow ½ inch deep in 4-inch pots; transplant gently 2–3 weeks after last frost.
Start brassica transplants indoors
Sow ¼ inch deep; transplant at 4–6 weeks when 4–5 inches tall; space 18 inches apart.
Sow ¼ inch deep; harden off well before transplanting; space 12–18 inches apart.
Sow ¼ inch deep; needs consistent cool temperatures; space 18 inches apart.
Sow ¼ inch deep directly or in trays; very cold-hardy; direct sow works well in cool soil.
🛠️ Maintenance
When to plant this month's crops in Zone 3
Full planting calendars — start indoors, transplant, and harvest timing — for the crops you're planting in March.
General March tasks
These apply broadly regardless of zone — a useful checklist alongside the zone-specific tasks above.
- ✓Direct sow peas, spinach, and lettuce outdoors once soil is workable
- ✓Start cucumbers, melons, and squash indoors (3–4 weeks before last frost)
- ✓Divide and transplant summer-blooming perennials
- ✓Apply compost or aged manure to vegetable beds
- ✓Plant shallots, onion sets, and bare-root strawberries
- ✓Set up cold frames and row covers for early crops
- ✓Begin hardening off seedlings started indoors
- ✓Plant cool-season annuals: pansies, snapdragons
⚠ Watch-outs for March
- ⚠Frost is still possible in most zones through March; protect transplants
- ⚠Soil may still be too wet and cold for many seeds — test by squeezing a handful
- ⚠Late snowfall can flatten young seedlings outdoors; have covers ready
- ⚠Slugs and snails become active early in spring; set bait or traps
March in Zone 3: common questions
What can I plant in March in Zone 3?＋
In March, Zone 3 gardeners can sow or transplant Cucumbers, Zucchini, Summer squash, Melons, Broccoli, Cabbage, Cauliflower, and Kale. March in Zone 3: indoor seed starting continues; ground thaws late in the month. Start squash and cucumbers indoors.
When is the last and first frost in Zone 3?＋
Zone 3 typically has its last spring frost around Mid May – early June and its first fall frost around Early September – early October, giving a growing season of roughly 100–130 days. Always check a local frost-date source, since microclimates vary.
What garden jobs matter most in March in Zone 3?＋
Focus on direct sow peas, spinach, and lettuce outdoors once soil is workable, start cucumbers, melons, and squash indoors (3–4 weeks before last frost), divide and transplant summer-blooming perennials. Watch out for frost is still possible in most zones through march; protect transplants.