When to Plant Basil: Zone-by-Zone Timing Guide
Basil is a warm-season annual herb that loves heat and cannot survive frost.
It bolts and grows poorly in cool weather, and its seeds rot in cold soil.
The two signals that set your planting date are your average last spring frost date and soil temperature.
The core rule: wait until all frost risk has passed, nights stay above about 50°F (10°C), and the soil has warmed to at least 60°F (15°C) — ideally around 70°F (21°C) — before sowing or transplanting outdoors.
In short seasons, start seeds indoors about 6 weeks before the last frost.
Why Basil Needs Warm Soil
Basil is from the warm Mediterranean and tropics, and it is the most frost-tender of the common culinary herbs.
Cold soil below about 60°F (15°C) makes seeds rot or germinate poorly, and cold nights below 50°F (10°C) stall growth and can cause blackening or leaf damage.
Soil warmth matters more than the calendar month.
Don't rush basil — a week of warm air in spring does not mean the ground is ready, and a late frost will kill young plants outright.
Work Backward: Starting Seeds Indoors
To get a head start in short-season climates, sow basil seeds indoors about 6 weeks before your average last frost date.
Basil germinates quickly and easily in warm, moist conditions. Use a seed-starting mix, keep it at 70–80°F (21–27°C), and keep the soil lightly moist.
Harden off seedlings for a week or two before transplanting. If you have a long, warm season, direct sowing after the last frost works just as well.
- 6 weeks before last frost: sow basil seeds indoors for a head start.
- Keep soil at 70–80°F (21–27°C), lightly moist; seeds germinate in 5–14 days.
- Direct sow outdoors: after last frost, soil at least 60°F (15°C).
Zone-by-Zone Planting Windows
The table below shows representative transplant/direct-sow windows by USDA hardiness zone, based on published average last-frost dates.
Coastal and warm zones allow earlier, longer seasons; cool inland valleys are later and shorter.
Confirm your exact date with your county extension office or the Almanac frost-date lookup.
- Zones 3–4 (last frost mid-May to early June): transplant late May to early June.
- Zone 5 (last frost early to mid-May): transplant mid-to-late May.
- Zone 6 (last frost mid-April): transplant early-to-mid May.
- Zone 7 (last frost late March): transplant mid-to-late April.
- Zone 8 (last frost mid-February to early March): transplant March–April.
- Zone 9 (last frost mid-January to early February): transplant February–March.
- Zone 10 (no hard frost): grow nearly year-round; plant in fall/winter in the hottest zones.
Transplanting Outdoors Correctly
Set basil transplants out only when the soil is at least 60°F (15°C) and nights stay above 50°F (10°C).
Choose a sunny spot with fertile, well-drained soil. Space plants 8 to 12 inches apart.
Water well at planting, then keep the soil evenly moist — basil is not drought-tolerant and wilts quickly.
Pinch off flower buds as they appear to keep the plant producing leaves instead of going to seed.
Soil and Season Considerations
Basil grows best in warm weather and full sun, in rich, well-drained soil. It dislikes soggy roots, so plant in raised beds or well-drained ground.
In short seasons, choose compact or fast varieties and use black plastic mulch to warm the soil. Pinching regularly keeps plants bushy.
Basil is usually grown as a warm-season annual, dying at the first frost.
Signs You Planted Too Early or Too Late
Planted too early, basil seeds rot in cold soil, or seedlings blacken and stall in cold nights.
Planted too late in a short season, plants may bolt quickly in early fall or yield little before frost.
The fix: start seeds indoors on schedule, wait for warm soil, and pinch regularly to delay flowering and extend harvest.
Related Guides
FAQ
- 1
What month is best to plant basil?
Basil is planted after the last frost. In most of the U.S., that is from mid-May (Zone 6) through early June (Zones 3–4), once the soil has warmed. In warm zones it can be planted from March onward.
- 2
Can basil survive frost?
No. Basil is the most frost-tender of the common culinary herbs and is killed by any frost. Wait until all frost risk has passed.
- 3
What soil temperature does basil need?
Basil seeds and transplants need soil at least 60°F (15°C); about 70°F (21°C) is ideal. Cold soil below 60°F causes poor germination and stalled growth.
- 4
How many weeks before last frost do I start basil indoors?
About 6 weeks before your average last frost date. Basil germinates quickly, so you don't need as long a head start as with peppers or celery.
- 5
Why does my basil bolt (flower) so fast?
Basil bolts in heat and when not harvested regularly. Pinch off flower buds as they appear and harvest leaves often to keep the plant vegetative and productive.
Sources
Utah State University Extension — Basil in the Garden“Basil loves warm weather, lots of sun and plenty of moisture... plant after the last frost.”
NC State Extension — Central North Carolina Planting Calendar for Annual Vegetables, Fruits, and Herbs“It is safe to plant warm season crops like cucumbers, tomatoes, southern peas, and lima beans outside after the last average frost date.”
NC State Extension — Vegetable Gardening Handbook (Ch. 16)“Be sure to adjust the planting dates for a specific location by noting the frost date and counting backward on the calendar the days to maturity of the vegetables.”