When to plant basil by city
Start basil indoors 4–6 weeks before your last frost, plant them out 1–2 weeks after your last frost, or sow seed outdoors 1–3 weeks after your last frost, once the soil is at least 60°F. Here is what that means for 2027 in cities across the US, using each city’s average frost dates and the date its normal daily temperature reaches 60°F, so cool-spring places like Seattle wait for real warmth (NOAA 1991–2020). Pick the city with the climate most like yours, or enter your ZIP code above.
| City | Last frost | Start indoors | Plant out | Sow outdoors |
|---|---|---|---|---|
| Seattle, WA (9a) | Mar 13 | Apr 10–24 | May 29 – Jun 5 | May 29 – Jun 12 |
| Portland, OR (8b) | Feb 25 | Apr 5–19 | May 24–31 | May 24 – Jun 7 |
| Sacramento, CA (9b) | Jan 12 | Feb 15 – Mar 1 | Apr 5–12 | Apr 5–19 |
| Phoenix, AZ (10a) | Jan 5 | Dec 28 – Jan 11 | Feb 15–22 | Feb 15 – Mar 1 |
| Salt Lake City, UT (7b) | Mar 31 | Mar 20 – Apr 3 | May 8–15 | May 8–22 |
| Denver, CO (6a) | Apr 30 | Mar 29 – Apr 12 | May 17–24 | May 17–31 |
| Dallas, TX (8b) | Mar 2 | Jan 27 – Feb 10 | Mar 17–24 | Mar 17–31 |
| Minneapolis, MN (5a) | Apr 23 | Mar 31 – Apr 14 | May 19–26 | May 19 – Jun 2 |
| Kansas City, MO (6b) | Apr 4 | Mar 7–21 | Apr 25 – May 2 | Apr 25 – May 9 |
| Chicago, IL (6b) | Apr 10 | Apr 3–17 | May 22–29 | May 22 – Jun 5 |
| Columbus, OH (6b) | Apr 20 | Mar 19 – Apr 2 | May 7–14 | May 7–21 |
| Nashville, TN (7b) | Apr 1 | Feb 26 – Mar 12 | Apr 16–23 | Apr 16–30 |
| Atlanta, GA (8a) | Mar 24 | Feb 18 – Mar 4 | Apr 8–15 | Apr 8–22 |
| Raleigh, NC (8a) | Mar 28 | Feb 23 – Mar 9 | Apr 13–20 | Apr 13–27 |
| Philadelphia, PA (7b) | Mar 30 | Mar 9–23 | Apr 27 – May 4 | Apr 27 – May 11 |
| Boston, MA (7a) | Apr 4 | Apr 1–15 | May 20–27 | May 20 – Jun 3 |
In frost-free parts of Florida, southern California and the Gulf Coast, timing is about heat instead: plant basil in late winter or early spring and again in late summer.
Don’t go by the calendar alone. Basil planted into cold soil sit still for weeks; wait until the soil 4 inches down is at least 60°F and nights stay above 50°F.
Basil spacing
In a square-foot bed, plant 1 per square foot. In traditional rows, space plants about 12 inches apart with 18 inches between rows.
Pinch the tips to keep it bushy. Turns black below 40°F.
How to grow basil
Basil is a heat-loving annual herb and one of the easiest to grow from seed. A few plants are enough for a summer of pesto and salads, but it is very cold sensitive: leaves blacken below about 40°F, and frost kills it.
Sun and soil
Full sun, at least 6–8 hours, in rich, well-drained soil with a pH of about 6.0–7.5. Water about 1–1½ inches a week, keeping soil evenly moist but not soggy.
Planting
- Start seeds indoors 4–6 weeks before transplanting, ⅛–¼ inch deep. They germinate fastest in warm soil, 75–85°F.
- Transplant 1–2 weeks after the last frost, when soil is at least 60°F and nights stay above 50°F, or direct-sow 1–3 weeks after the frost date.
- Space plants 12 inches apart in rows 18 inches apart.
Care
- Pinch the growing tip just above a pair of leaves when plants are 6–8 inches tall; it branches and grows bushy.
- Remove flower spikes as they appear; flowering slows leaf production and weakens flavor.
- Water at the base and mulch once the soil is warm.
- Sow or plant a second round in midsummer for a fresh crop into fall.
Harvest
Start picking once plants have 6–8 sets of leaves. Cut stems just above a pair of leaves, taking up to a third of the plant at a time. Harvest everything before nights drop into the 30s. Keep cut basil at room temperature in water; the refrigerator blackens it.
Common problems
- Basil downy mildew: Yellowing leaves with gray-purple fuzz underneath, spreading fast in humid weather. Grow resistant varieties, space plants, water in the morning, and pull infected plants.
- Fusarium wilt: Plants wilt and stems show brown streaks. There is no cure; remove plants, buy disease-free seed or resistant varieties, and plant elsewhere next year.
- Cold injury: Leaves turn black after chilly nights. Do not plant out too early, and cover or harvest before cold snaps.
- Japanese beetles and slugs: Hand-pick beetles in the morning; trap or hand-pick slugs in the evening.
Varieties to try
- 'Genovese' — classic large-leaf Italian basil for pesto
- 'Prospera' — Genovese type bred to resist downy mildew
- 'Thai' — anise-clove flavor, purple stems
- 'Spicy Globe' — small leaves on a compact mound
Crop rotation
Basil belong to the mint family (Lamiaceae). Mostly herbs and perennials; rotation matters little. Relatives that count as the same family for rotation: mint, oregano, thyme, sage, rosemary.
Frequently asked questions
When should I plant basil?
What grows well with basil?
How far apart should I plant basil?
How long do basil take to grow?
Can basil handle frost?
Sources
- Frost dates: NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020.
- Hardiness zones: 2023 USDA Plant Hardiness Zone Map, USDA-ARS and PRISM Climate Group, Oregon State University.
- Planting windows and spacing: Vegetable Planting Guide (GardenNotes #720), Colorado State University Extension, and other land-grant extension guides.
- Basil in the Garden — Utah State University Extension
- Herbs — Clemson Cooperative Extension (HGIC)