What to plant in March in USDA zone 9

Sow outdoors in March — zone 9

Direct-sow these seeds into prepared garden beds or large containers. Soil temperature matters more than the calendar date — wait for a sustained warm-up before sowing tender crops.

• Warm-season crops in full swing — tomatoes, peppers, beans, squash, okra, melons
• Sweet potatoes (transplant slips)

Harvest in March — zone 9

These crops should be ready or in active harvest in March for zone 9 gardens. Pick fruiting crops every 2-3 days to keep production going.

• Strawberries, citrus, spring greens

Maintenance in March — zone 9

• Mulch tomato and pepper beds — Conserve soil moisture before summer heat.

Universal March tasks

These apply across most US and UK gardens in March, regardless of zone.

• Start tomato, pepper, and eggplant seeds indoors (if not already).
• Direct-sow peas, spinach, lettuce, radishes once soil is workable.
• Transplant onions and leeks outdoors in zones 5-9.
• Plant bare-root fruit trees, berries, and asparagus crowns.
• Prune roses just before they break dormancy.
• Top-dress beds with compost and start hardening off transplants.

Why this works for zone 9

Zone 9 has average annual minimum temperatures of 20 to 30°F (-7 to -1°C) and a frost-free window from mid-February to early March to late November / early December — about 280 growing days. Heat-tolerant tomato varieties (Solar Fire, Heatwave II) needed for midsummer. Cool-season crops grow Oct-Apr while northern zones are dormant.

Dates are zone-wide averages. Local microclimates (south-facing slopes, urban heat, lakeside warmth, elevation) can shift the window by 1-2 weeks within the same zone.

UK gardeners — March

March opens outdoor sowing for most of the UK. Direct-sow peas, broad beans, spinach, radishes, and early carrots under cloches. Indoor: tomatoes, peppers, aubergines, cucumbers. Plant first early potatoes mid-month.

Source and methodology

Frost-date averages from NOAA Climate Data Online within USDA zone 9. Hardiness boundaries from the USDA Plant Hardiness Zone Map (2023). Crop timing curated against US Cooperative Extension Service publications (UNL, UMN, NC State, Texas A&M, UF/IFAS, Oregon State) and cross-referenced against the RHS sowing calendar. Curated by the Growli editorial team.

Keep going

• ← February in zone 9
• April in zone 9 →
• All zones — what to plant in March
• USDA Zone 9 — frost dates and crop list
• Full 12-month planting calendar

Other zones — March

• What to plant in March in zone 3
• What to plant in March in zone 4
• What to plant in March in zone 5
• What to plant in March in zone 6
• What to plant in March in zone 7
• What to plant in March in zone 8
• What to plant in March in zone 10