What to Plant in March
Zone-by-zone guide to March planting — vegetables, flowers, herbs, and trees. Indoor seed starting schedules plus outdoor planting windows for every USDA zone.
March is the month everything changes. For most gardeners, it's the busiest planting month of the year — indoor seed starting kicks into high gear, cool-season crops go into the ground, and warm-zone gardeners are already transplanting summer favorites. Whether you're in zone 3 counting down to thaw or zone 10 harvesting your first spring tomatoes, this guide covers exactly what to plant in March for your zone.
🌱 Start Indoors in March
Tomatoes (Zones 3–6)
March is THE month to start tomato seeds indoors for zones 3–6. Sow 6–8 weeks before your last frost date. Use a heat mat (tomatoes germinate best at 75–85°F). Harden off gradually in late April/May. Start with cherry tomatoes for beginners — they're the most forgiving. Determinate varieties for containers, indeterminate for garden beds.
Peppers (All Zones)
Start pepper seeds indoors 8–10 weeks before last frost — March is ideal for most of the US. Peppers need WARMTH (80–90°F for germination). Use a heat mat and dome. Bell peppers, jalapeños, and habaneros all start now. Peppers are slow growers — starting early is critical. Don't transplant outdoors until nighttime temps stay above 55°F.
Eggplant
Start eggplant seeds 8–10 weeks before last frost. Like peppers, they need warm soil (80°F) for germination. Use a heat mat and keep under grow lights 14–16 hours/day. Eggplant is a long-season crop — starting in March gives enough time for zones 3–7. Varieties: Black Beauty (classic), Ichiban (Japanese long), Fairy Tale (compact for containers).
Broccoli & Cauliflower (Zones 3–5)
Start brassicas indoors 6–8 weeks before last frost for zones 3–5. Broccoli, cauliflower, cabbage, Brussels sprouts — all cool-season crops that need an early start in cold climates. They tolerate light frost once transplanted. Grow at 60–65°F — too warm and seedlings get leggy. Transplant outdoors 2–4 weeks before last frost.
Herbs: Basil, Parsley, Cilantro
Start basil indoors 6–8 weeks before last frost. Basil needs warmth — 70°F+ for germination. Parsley is slow to germinate (2–3 weeks) so start early. Cilantro bolts in heat so start early and plan succession sowings. Also start: chives, oregano, thyme, sage. Herbs in 4-inch pots transplant easily to gardens or containers.
Annual Flowers: Marigolds, Zinnias, Cosmos
Start annual flower seeds indoors 4–6 weeks before last frost. Marigolds, zinnias, cosmos, sunflowers, celosia — all easy from seed. Direct sow after frost for easiest approach, but indoor starts give you a 4–6 week head start on blooms. Use seed starting mix, not garden soil. Transplant at true leaf stage.
☀️ Plant Outdoors in March — Warm Zones (8–10)
Tomato Transplants (Zones 9–10)
Zones 9–10 can transplant tomatoes outdoors in March — your last frost has already passed. Set transplants in full sun, 24–36 in apart. Add a cage or stake at planting time. Water deeply at planting and mulch with 3 in of straw or wood chips. In zone 9, watch for late cold snaps and keep frost cloth handy.
Peppers & Eggplant (Zones 9–10)
Warm-zone gardeners can transplant peppers and eggplant in March. Soil temps should be consistently above 65°F. Plant in full sun with rich, well-drained soil. Space peppers 18–24 in apart, eggplant 24–36 in. Mulch heavily to retain moisture. In zone 10 (South Florida, SoCal), these are already growing strong by March.
Squash, Cucumbers, Melons (Zones 9–10)
Direct sow warm-season crops in zones 9–10 once soil is consistently above 70°F. Summer squash, zucchini, cucumbers, cantaloupe, watermelon — all can go directly in the ground. Plant in hills (mounded soil) for better drainage. Space vining types 4–6 ft apart. Bush varieties work for smaller spaces.
Beans (Zones 8–10)
Direct sow bush beans and pole beans when soil temps hit 60°F — mid-to-late March in zones 8–10. Beans don't transplant well — always direct sow. Plant 1 in deep, 3–4 in apart. Bush beans produce quickly (50–60 days). Pole beans produce longer but need a trellis. Inoculate seeds with rhizobium for better nitrogen fixation.
Spring Flowers: Petunias, Geraniums, Lantana (Zones 8–10)
Warm zones can plant tender annuals outdoors in March. Petunias, geraniums, lantana, pentas, vinca — all available at nurseries. Plant after the last average frost date. These heat-lovers will bloom through fall. In zone 10, you can plant nearly anything year-round. Container plantings refresh immediately.
Citrus Trees (Zones 9–10)
March is excellent for planting citrus trees in warm zones. Meyer lemon, key lime, Valencia orange, grapefruit — all thrive in zones 9–10. Plant in full sun with well-drained soil. Water deeply weekly for the first year. Container citrus can be planted anytime but March gives a full growing season to establish.
❄️ Plant Outdoors in March — Cool/Cold Zones (3–7)
Peas (Zones 4–7)
Peas are one of the earliest outdoor crops — plant 4–6 weeks before last frost. In zones 5–7, that's often mid-to-late March. Peas germinate in soil as cool as 40°F. Direct sow 1 in deep, 2 in apart along a trellis or fence. Snow peas, snap peas, and shelling peas all plant at the same time. They stop producing in summer heat.
Lettuce & Salad Greens (Zones 5–7)
Direct sow lettuce, spinach, arugula, and mesclun in March for zones 5–7. These cool-season crops thrive in 40–65°F. Scatter seed thinly, cover lightly (1/8 in), keep moist. Harvest in 30–45 days. Succession sow every 2 weeks for continuous harvest through spring. Cover with row fabric for extra protection in zones 5–6.
Radishes & Carrots (Zones 5–7)
Direct sow radishes 4–6 weeks before last frost — they're ready in 25–30 days. Carrots take longer (60–80 days) but can be sown in March for zones 6–7. Both need loose, stone-free soil. Radishes: sow 1/2 in deep, thin to 2 in apart. Carrots: sow on surface, barely cover, keep moist. Radishes are the perfect beginner crop.
Onion Sets & Transplants (Zones 4–7)
March is prime onion planting time for most zones. Plant onion sets (small bulbs) or transplants 4–6 weeks before last frost. Sets go 1 in deep, 4–6 in apart. Choose long-day varieties for zones 4–6, intermediate for zone 7. Also plant shallots and garlic (if not planted in fall). Green onions can be direct sown — harvest in 60 days.
Potatoes (Zones 5–7)
St. Patrick's Day is the traditional potato planting date for many zones. Plant seed potatoes 4 in deep, 12 in apart in trenches when soil is at least 45°F. Hill soil around stems as they grow. Early varieties (Yukon Gold, Red Pontiac) are ready in 70–90 days. Late varieties (Russet, Kennebec) take 90–120 days. Don't plant grocery store potatoes — they may carry disease.
Bare-Root Trees & Shrubs (Zones 4–7)
March is the ideal time to plant bare-root fruit trees, roses, and ornamental trees. They're dormant, affordable (40–60% less than potted), and establish faster. Soak roots in water for 1–2 hours before planting. Spread roots in a wide hole, backfill with native soil, water deeply. Bare-root season is short — order early, plant immediately upon arrival.
🌸 March Flower Planting
Plant Summer Bulbs Indoors
Start dahlias, canna lilies, caladiums, and elephant ears in pots indoors in March. These tender bulbs need a head start — plant 4–6 weeks before outdoor planting time. Use 6–8 in pots, plant at the correct depth (dahlias 4 in, cannas 2–4 in), and keep warm (65–75°F). Transplant outdoors after last frost. This gives you blooms 4–6 weeks earlier.
Pansies & Violas (Zones 5–8)
Plant pansies and violas outdoors in March — they handle light frost and bloom in cool weather. Available at nurseries everywhere in March. Colors: purple, yellow, blue, white, orange, multicolor. Plant in full sun to part shade. Feed every 2 weeks for continuous bloom. They'll bloom through spring until summer heat kills them.
Sweet Peas (Zones 5–8)
Direct sow sweet pea seeds as early as soil can be worked — they need cool weather to thrive. Soak seeds overnight, nick the seed coat, plant 1 in deep along a trellis or fence. Sweet peas are one of the most fragrant cut flowers. They climb 6–8 ft. Plant in full sun, keep roots cool with mulch. They stop blooming in summer heat.
Snapdragons (Zones 6–8)
Plant snapdragon transplants outdoors in March — they're cool-season flowers that tolerate light frost. Available in dwarf (8 in), medium (18 in), and tall (36 in) varieties. Gorgeous vertical color for beds and containers. Colors: every shade except blue. They may survive mild winters and rebloom the following spring.
Hardy Perennials (Zones 4–7)
March is an excellent time to plant or divide perennials. Hostas, daylilies, coneflowers, black-eyed Susans, sedum, coral bells — all can be planted or divided now while dormant. Divide overgrown clumps by digging up the root ball and splitting into sections with a sharp spade. Replant at the same depth. Water deeply.
Native Wildflower Seeds (Zones 5–8)
Scatter native wildflower seed mix on prepared soil in March. Cool-season stratification (cold temps + moisture) triggers germination. Clear existing vegetation, scatter seed at recommended rates, and press into soil contact (don't bury deeply). Don't mow until after seeds have set (usually late summer). A wildflower meadow is one of the lowest-maintenance landscapes possible.
📋 March Garden Tasks
Soil Prep & Amendment
As soon as soil is workable (not frozen or waterlogged), start prepping beds. Add 2–3 in of compost and work into the top 6–8 in. Test soil pH — most vegetables prefer 6.0–7.0. If you haven't tested in 3+ years, send a sample to your local extension service ($15–$25). Good soil is the foundation of every great garden.
Prune Summer-Blooming Shrubs
Prune shrubs that bloom on NEW wood (this year's growth) in late winter/early March: butterfly bush, crape myrtle, roses (hybrid tea, floribunda), spirea (summer-blooming types), hydrangea (Annabelle, panicle types). DO NOT prune spring-blooming shrubs (lilac, forsythia, azalea) — they bloom on old wood and pruning now removes this year's flowers.
Apply Pre-Emergent (Warm Zones)
In zones 7–10, apply pre-emergent herbicide in early March to prevent summer weeds (crabgrass, goosegrass). Apply when soil temps reach 55°F for several consecutive days. This is a timing game — too late and weed seeds have already germinated. For organic options, corn gluten meal works as a natural pre-emergent.
Clean Up Winter Debris
Remove dead leaves, fallen branches, and winter mulch as temperatures warm. Cut back dead perennial stalks you left for winter interest. Clean out gutters and downspouts. Power wash hardscaping. This is the 'spring reset' — everything looks better immediately after cleanup. Wait until daytime temps are consistently above 50°F so overwintering beneficials have emerged.
Order Seeds & Plants
If you haven't ordered seeds yet, March is your last chance for many specialty varieties. Popular tomato, pepper, and flower varieties sell out by mid-March. Check: Baker Creek, Johnny's Selected Seeds, Burpee, Park Seed. For bare-root trees and shrubs, order NOW — bare-root season ends in April for most zones.
Fertilize Cool-Season Lawns (Zones 5–7)
Apply the first spring fertilizer to cool-season lawns (Kentucky bluegrass, fescue, rye) in March when grass begins greening up. Use a slow-release nitrogen fertilizer at 1 lb N per 1,000 sq ft. Don't over-fertilize — more isn't better. For warm-season lawns (Bermuda, zoysia, St. Augustine), wait until the grass is actively growing (usually April–May).
March Planting Quick Reference
| Plant | Start Indoors | Plant Outdoors | Days to Harvest | Zones | Sun | Difficulty |
|---|---|---|---|---|---|---|
| Tomatoes | March (zones 3–6) | After frost (May–June) | 60–85 | 3–11 | Full sun | Easy |
| Peppers | March (all zones) | After frost, soil 65°F+ | 60–90 | 3–11 | Full sun | Easy |
| Peas | N/A (direct sow) | 4–6 wks before frost | 55–70 | 2–11 | Full to part sun | Easy |
| Lettuce | Optional | As soon as workable | 30–45 | 3–11 | Full to part sun | Very easy |
| Potatoes | N/A (direct plant) | March (zones 5–7) | 70–120 | 3–10 | Full sun | Easy |
| Onions | Jan–Feb | March (zones 4–7) | 90–120 | 3–9 | Full sun | Moderate |
| Broccoli | March (zones 3–5) | 2–4 wks before frost | 60–80 | 3–10 | Full sun | Moderate |
| Pansies | N/A (buy transplants) | March (zones 5–8) | Immediate bloom | 4–9 | Full to part sun | Very easy |
Frequently Asked Questions
Is March too early to plant outside?
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It depends on your zone. In zones 8–10, March is prime outdoor planting time for most crops. In zones 5–7, you can plant cool-season crops (peas, lettuce, radishes, potatoes) outdoors, but wait until after your last frost date for warm-season crops (tomatoes, peppers). In zones 3–4, March is almost entirely an indoor seed-starting month.
What vegetables can I start indoors in March?
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Tomatoes, peppers, eggplant, broccoli, cauliflower, cabbage, herbs (basil, parsley), and annual flowers (marigolds, zinnias, cosmos). Start 6–10 weeks before your last frost date. Use a heat mat for peppers and tomatoes — they germinate best at 75–85°F.
Can I plant potatoes in March?
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Yes — in zones 5–7, mid-to-late March is ideal for potatoes. The traditional date is St. Patrick's Day (March 17). Plant when soil is at least 45°F. In zones 8–9, plant in February. In zones 3–4, wait until late April or early May.
What flowers can I plant outside in March?
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Cool-season flowers that tolerate frost: pansies, violas, sweet peas, snapdragons, dianthus, alyssum, stock, dusty miller. Also plant/divide hardy perennials: daylilies, hostas, coneflowers, sedum. Wait until after last frost for tender annuals like marigolds, petunias, and impatiens.
Should I fertilize my lawn in March?
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For cool-season lawns (bluegrass, fescue): yes, apply slow-release fertilizer when grass starts greening up. For warm-season lawns (Bermuda, zoysia): wait until the grass is actively growing, usually April–May. Never fertilize dormant warm-season grass.
How do I know when it's safe to plant outdoors?
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Look up your USDA zone's average last frost date. Zones 3–4: May 15–June 1. Zone 5: April 15–May 15. Zone 6: April 1–30. Zone 7: March 15–April 15. Zone 8: March 1–15. Zones 9–10: February or earlier. Plant cool-season crops 4–6 weeks BEFORE last frost. Plant warm-season crops AFTER last frost.
Visualize Your March Garden
Upload a photo of your yard and see how March plantings will look in all four seasons — spring blooms through winter structure.
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