March is the month the garden wakes up. The average last frost in Zone 8 is Mar 1–15, so March is the pivot: hardy crops go out with confidence, tender crops go out only at the very end of the month and only with protection, and the seed-starting table is at its busiest. Get March right and the whole summer follows.
What March means in Zone 8
USDA Zone 8 runs through the southern United States, from parts of Texas, Louisiana, Georgia and South Carolina to the Pacific Northwest coast and parts of California. Winters are mild, with average winter lows of 10 to 20°F, and the growing season is long, which gives Zone 8 gardeners one of the most forgiving calendars in the country.
The dates that matter most are the frost averages. The average last spring frost in Zone 8 is Mar 1–15, and the average first autumn frost is Nov 15–Dec 1. These are USDA zone averages drawn from NOAA frost records, not exact dates for any one garden. Always check your local extension service and the forecast before planting tender crops outside. Use our frost date calculator for your zone’s averages.
March in Zone 8 is the pivot of the year: the average last frost falls in the first half of the month, so tomatoes and peppers can go out in the second half. Direct-sow beans and corn once the soil feels warm, and do not rush them: cold, wet soil rots bean seed faster than anything else.
March task list
- Sow peas, carrots, beets, lettuce, spinach and radishes outdoors.
- Start cucumbers, squash, melons and basil indoors.
- Transplant tomatoes, peppers and eggplant after the last frost, hardening off first.
- Plant potatoes, onion sets and shallots.
- Feed and mulch beds, and top-dress perennials with compost.
- Sow beans and corn outdoors once the soil warms.
- Watch the forecast nightly: keep fleece and cloches ready for late frosts.
What to start indoors in March
Start these under cover now, with strong light and steady moisture.
- Cucumbers — matures in 50–70 days; tender; soil pH 6.0–7.0.
- Zucchini — matures in 45–55 days; tender; soil pH 6.0–7.5.
- Basil — matures in 60–70 days; tender; soil pH 6.0–7.5.
- Butternut squash — matures in 90–110 days; tender; soil pH 6.0–7.0.
What to direct-sow in March
Sow these straight into prepared beds and water the seed row well.
- Green beans — matures in 50–65 days; tender; soil pH 6.0–7.0.
- Sweet corn — matures in 60–90 days; tender; soil pH 6.0–6.8.
- Carrots — matures in 60–80 days; hardy; soil pH 6.0–6.8.
- Beets — matures in 50–70 days; hardy; soil pH 6.0–7.0.
- Lettuce — matures in 45–60 days; hardy; soil pH 6.0–7.0.
What to transplant in March
Harden seedlings off for a week before planting out, and water them in well.
- Tomatoes — matures in 60–85 days; tender; soil pH 6.0–6.8.
- Bell peppers — matures in 60–90 days; tender; soil pH 6.0–6.8.
- Eggplant — matures in 70–85 days; tender; soil pH 6.0–6.8.
- Basil — matures in 60–70 days; tender; soil pH 6.0–7.5.
What to harvest in March
Pick little and often: regular picking keeps beans, squash and cucumbers producing.
- Peas — hardy, matures in 60–70 days.
- Lettuce — hardy, matures in 45–60 days.
- Spinach — hardy, matures in 40–50 days.
- Broccoli — frost-tolerant, matures in 60–85 days.
- Radishes — hardy, matures in 25–40 days.
- Asparagus — hardy, matures in 730–1095 days.
March planting at a glance
| Crop | What to do | Days to maturity | Cold tolerance | Spacing |
|---|---|---|---|---|
| Cucumbers | Start indoors | 50–70 | tender | 36–48 in |
| Zucchini | Start indoors | 45–55 | tender | 36–48 in |
| Basil | Start indoors | 60–70 | tender | 12–18 in |
| Butternut squash | Start indoors | 90–110 | tender | 48–72 in |
| Green beans | Direct sow | 50–65 | tender | 4–6 in |
All figures are broad published ranges from standard horticultural references, and they vary by variety, soil and weather. Check your local extension service for advice on your own garden.
Soil, water and feeding in March
March soil warms fast on sunny days but cools at night, so mulch newly planted beds to even out the swing. Water seedlings in the morning so leaves dry before nightfall, which cuts fungal disease. Feed hungry crops like brassicas with a balanced fertiliser once they are growing strongly.
Frost and weather protection
March frost is the trap of the Zone 8 year. The average last spring frost is Mar 1–15, which means about half of years will see a frost after that date, so tender transplants need hardening off and a fleece cover on cold nights. Hardy crops shrug off a light frost, but tomatoes, peppers and beans will not. Check your local extension service and the ten-day forecast before planting anything tender outside.
Pests and problems to watch
Aphids arrive with the first warm days and cluster on new growth: squash them by hand or wash them off with water. Slugs and snails are active in damp March weather, so protect young lettuce and peas. Watch brassicas for cabbage white butterflies and net them if you see them.
Frequently asked questions
When can I plant tomatoes outside in Zone 8?
After the average last frost, Mar 1–15, and only when night temperatures stay above about 50°F. Harden seedlings off for a week first, and keep fleece handy for a late cold snap.
What can I direct-sow in March in Zone 8?
Peas, carrots, beets, lettuce, spinach, radishes and broad beans. Beans and corn should wait until the soil has warmed, usually late March or April.
Should I plant potatoes in March in Zone 8?
Yes: March is the main potato-planting month. Plant chitted seed potatoes in trenches once the soil is workable, and earth them up as shoots appear.
How do I protect seedlings from a late frost?
Cover them with horticultural fleece, cloches or even upturned buckets overnight, and remove the cover in the morning. Water the soil before a frost: moist soil holds heat better than dry soil.
For the full year, browse the planting calendar hub. Nearby months: February in Zone 8, April in Zone 8, March in Zone 9. Use the planting calendar by ZIP to work out exact dates for your own garden.