When to Plant Basil in New Hampshire
The king of herbs. Basil and tomatoes are best friends in the garden and in the kitchen.
The Short Answer
New Hampshire Frost Dates
Your planting dates depend on which part of New Hampshire you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern New Hampshire | 3b, 4a, 4b | May 20 - Jun 5 | Sep 10 - Sep 25 |
| Southern New Hampshire | 5a, 5b, 6a | May 1 - May 20 | Sep 25 - Oct 10 |
Basil Planting Schedule for New Hampshire
Northern New Hampshire (Zones 3b, 4a, 4b)
Average last frost: May 20 - Jun 5 · Average first frost: Sep 10 - Sep 25
Southern New Hampshire (Zones 5a, 5b, 6a)
Average last frost: May 1 - May 20 · Average first frost: Sep 25 - Oct 10
Growing Basil in New Hampshire
Basil in New Hampshire's Climate
Basil needs warmth and dies at the first hint of frost. Start seeds indoors 6 weeks before your last frost and don't transplant until nights stay above 55°F — often 2-3 weeks after your official last frost date. Your growing window may be only 10-14 weeks, so make them count: pinch flower buds aggressively and harvest often. Consider growing in containers you can move indoors during unexpected cold snaps.
Soil Considerations for New Hampshire
Rocky, acidic New England soils. Glacial deposits. Granite bedrock. Raised beds essential in many areas. Make sure soil has warmed to at least 60°F before planting basil outside.
New Hampshire Climate & Growing Season
Short growing season especially in north. Cold winters. Cool summers. Hardy varieties important. Basil cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.
Growing season length varies across New Hampshire: Northern New Hampshire (3b, 4a, 4b) has a last frost around May 20 - Jun 5, while Southern New Hampshire (5a, 5b, 6a) sees frost end around May 1 - May 20. This difference matters for basil — transplant timing shifts by several weeks across the state.
Growing Tips
Pinch off flower buds to keep leaves producing. Harvest from the top down, cutting just above a leaf pair. Succession plant for season-long supply.
Companion Planting
Plant basil alongside these companions for better growth:
Keep basil away from:
The Bottom Line
Last reviewed: March 29, 2026