What to Plant in March — Spring Garden Guide by Zone 2026

What to plant in March by USDA hardiness zone

Zones 5–6 — Indoor season in full force, outdoor cautiously begins

In Zones 5-6 (Upper Midwest, New England, Mountain states), March typically brings the last major snowstorms and certainly sub-freezing temperatures at night. But the increasing day length (12+ hours in March) makes this the right time to push the indoor seed-starting operation into full gear.

• Start tomatoes indoors (critical timing): Zone 5 last frost is May 15-30, so start tomatoes March 1-15 (6-8 weeks ahead). Zone 6 last frost is May 1-15, so start March 1-20. Use bottom heat (70-75°F) and grow lights 14-16 hours/day. Without adequate light, seedlings will be leggy and weak.
• Start peppers and eggplant: These need 8-10 weeks, so March start is essential for Zone 5-6. They're more temperature-sensitive than tomatoes — soil temp of 75-80°F dramatically improves germination.
• Start onions and leeks: If you didn't start these in February, start immediately. They need 10-12 weeks to reach transplant size. Sow 5-6 seeds per cell, thin to 2-3 per cell for bunch green onions or 1 per cell for large bulbs.
• Direct sow outdoors (late March, Zone 6 only): When soil reaches 40°F (mid-to-late March in Zone 6), direct sow peas, spinach, and mâche. These are cold-tolerant enough to germinate in cool soil. Cover with row cover to accelerate warming.

Zones 7–8 — Outdoor planting opens up

Zone 7-8 (Mid-Atlantic, Pacific Northwest, Upper South) sees last frost arriving in March (Zone 8) to mid-April (Zone 7). March outdoor planting is very much possible for cool-season crops, while the indoor operation produces the warm-season transplants that go out in April-May.

• Direct sow outdoors (early March): Peas as soon as soil is workable (Zone 7 can even start in late February). Spinach, arugula, lettuce, radishes, beets, carrots, and Swiss chard throughout March. Plant in beds covered with row cover for faster soil warming and earlier harvest.
• Transplant cool-season crops (mid-March): Broccoli, cabbage, and kale transplants that were started in January can go out in mid-March in Zone 8 under row cover. Zone 7 — wait until early April unless you have row cover protection.
• Indoor starts: Start tomatoes and peppers 6-8 weeks before last frost. Zone 8 last frost is mid-March, so these may already be running. Zone 7 (April 15 last frost) — start March 1-15.
• Plant potatoes: March is prime potato-planting month for Zone 7-8. Chit (pre-sprout) seed potatoes 2-3 weeks before planting by placing in a cool, bright location. Plant 4 inches deep, 12 inches apart, rows 30 inches apart.

Zones 9–11 — Spring or late-fall depending on location

Zone 9-11 gardeners have a split experience in March. This is either the transition out of the winter cool-season garden (Zone 9-10 in the South) or the start of the main spring planting season (California, Pacific Northwest Zone 9). Either way, March is active.

• Zone 9-10 (South): transition month. Cool-season crops (broccoli, lettuce, peas) planted in October-November are finishing up. Start transitioning to warm-season crops: direct sow beans and squash in Zone 9, transplant tomatoes and peppers outdoors in Zone 10.
• Zone 9 (California): prime spring planting. Direct sow tomatoes, squash, beans, and cucumbers in warm coastal areas. Transplant tomato and pepper starts outdoors from mid-March in Zones 9b-10a. Direct sow basil, cilantro, and summer herbs.
• Zone 10-11 (Hawaii, South Florida): summer preparation. Direct sow heat-tolerant crops: yard-long beans, Malabar spinach, okra, sweet potatoes, and heat-resistant basil varieties. March is the last good window before summer heat arrives.

March planting calendar by USDA zone

Indoor seed starting in March: the complete guide

Success with tomatoes and peppers starts with getting the indoor growing environment right. Here's the system that produces the strongest transplants.

Equipment you need

• Seed starting mix: Not potting soil — seed starting mix is finer, lighter, and sterile. Potting soil is too dense for germination and may harbor pathogens that cause damping-off (a fatal seedling fungal disease).
• Heat mat: Essential for tomatoes, peppers, and eggplant. These tropical crops won't germinate reliably below 65°F — with a heat mat maintaining 70-75°F soil, germination happens in 5-7 days. Without one, expect 2-3 weeks of patchy germination.
• Grow lights: Natural windowsill light in March is insufficient for strong seedlings. Use T5 fluorescent or LED grow lights positioned 2-4 inches above seedling tops. Run 14-16 hours/day on a timer. Leggy seedlings = not enough light.
• Small fan: Run a small fan on seedlings for 1-2 hours per day. This strengthens stems through mechanical stimulation and prevents fungal issues from stagnant humid air.

Step-by-step tomato seed starting

1. Fill cells or pots with moist seed starting mix. Tamp lightly — no air pockets, but don't compact.
2. Plant 2 seeds per cell at 1/4 inch deep. Cover lightly with vermiculite or seed starting mix.
3. Mist surface with a spray bottle, cover with plastic dome, place on heat mat.
4. Germination occurs in 5-10 days at 70-75°F. Remove dome immediately when you see sprouts — continued humidity causes damping-off.
5. Move immediately to grow lights. Place lights 2 inches above seedling tops. Raise as plants grow.
6. Thin to 1 per cell when cotyledons are fully open — snip the weaker seedling at soil level.
7. Water carefully: Allow the top 1/2 inch of mix to dry between waterings. Bottom-watering (placing tray in water for 20 minutes) reduces damping-off risk.

March outdoor planting: how to work with cold soil

Cool-season crops planted directly in March soil temperatures of 40-50°F will germinate slowly but reliably. These techniques accelerate the process and improve germination rates.

• Pre-warm soil with row cover: Lay floating row cover (or even clear plastic) over prepared beds 1-2 weeks before sowing. This can raise soil temperature 5-10°F, dramatically speeding germination.
• Raised beds warm faster: Raised beds can be 10-15°F warmer than in-ground beds in March. If you have both, prioritize raised beds for early March sowings.
• Sow thicker than normal: Cool soil means lower germination rates. Sow carrot and lettuce seeds at 2x the normal rate and thin to proper spacing after germination.
• Direct sow peas as soon as soil is workable: Peas germinate in 35-40°F soil and tolerate hard frost. Every week earlier you plant peas is another week of harvest before summer heat shuts them down.

Frequently asked questions about what to plant in March