Blog

When to Plant Thai Basil in New Hampshire

Thai basil has a distinctive anise-licorice flavor with sturdy purple stems and small leaves. It is essential in Thai, Vietnamese, and other Southeast Asian cuisines.

New Hampshire spans USDA hardiness zones 4a, 4b, 5a, 5b (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

Find Your County

Click your county for exact Thai Basil planting dates based on your local frost dates.

Hover over a county to see details. Click to view planting guide.

Thai Basil Planting Calendar for New Hampshire

โ–ธ Zone 4a ~145 day growing season ยท Full guide โ†’

Last frost: May 6 ยท First frost: September 28 ยท 145 day season

Activity When Date Range
Start Indoors March 11 Mar 11 โ€“ Mar 25
Transplant Outdoors May 27 May 27 โ€“ Jun 10
Direct Sow May 13 May 13 โ€“ Jun 3
Harvest July 22 Jul 22 โ€“ Sep 23
โ–ธ Zone 4b ~155 day growing season ยท Full guide โ†’

Last frost: May 1 ยท First frost: October 3 ยท 155 day season

Activity When Date Range
Start Indoors March 6 Mar 6 โ€“ Mar 20
Transplant Outdoors May 22 May 22 โ€“ Jun 5
Direct Sow May 8 May 8 โ€“ May 29
Harvest July 17 Jul 17 โ€“ Sep 18
โ–ธ Zone 5a ~166 day growing season ยท Full guide โ†’

Last frost: April 25 ยท First frost: October 8 ยท 166 day season

Activity When Date Range
Start Indoors March 7 Mar 7 โ€“ Mar 21
Transplant Outdoors May 9 May 9 โ€“ May 23
Direct Sow May 2 May 2 โ€“ May 23
Harvest July 4 Jul 4 โ€“ Sep 5
โ–ธ Zone 5b ~178 day growing season ยท Full guide โ†’

Last frost: April 18 ยท First frost: October 13 ยท 178 day season

Activity When Date Range
Start Indoors February 28 Feb 28 โ€“ Mar 14
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 25 Apr 25 โ€“ May 16
Harvest June 27 Jun 27 โ€“ Aug 29

Growing Tips for New Hampshire

Start seeds indoors or direct sow after last frost. Thai basil holds up better to heat in cooking than sweet basil. Pinch flowers to prolong leaf production.

Frequently Asked Questions

When should I plant Thai Basil in New Hampshire?

Planting dates for Thai Basil in New Hampshire depend on your USDA zone. New Hampshire spans zones 4a, 4b, 5a, 5b. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is New Hampshire for planting?

New Hampshire contains USDA hardiness zones 4a, 4b, 5a, 5b. Your specific zone depends on your location within the state โ€” northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Last updated: April 2026.