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When to Plant Catnip in Grafton County, NH

Catnip is a hardy perennial herb in the mint family known for its effect on cats. It also makes a calming tea and is a useful companion plant that repels some pests.

Grafton County, New Hampshire is in USDA Zone 4b. The average last spring frost is May 12 and the first fall frost is October 7, giving you a growing season of approximately 148 days.

At an elevation of 524 feet, Grafton County receives approximately 44.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Catnip to ensure they mature before fall.

Grafton County, NH (Zone 4b) Short season
148 days
Last Spring Frost May 12
148 growing days
First Fall Frost October 7

Grafton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Sep 16
Recommended (50%) ✓ Fits season (15 days to spare)
Transplant: May 19 🍅 Harvest: Jul 21 – Sep 22
Safe Start (90%) ✓ Fits season (15 days to spare)
Transplant: Jun 1 🍅 Harvest: Aug 3 – Oct 5

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Catnip needs ~700 GDD — county provides 1,480 GDD Excellent fit

Catnip Planting Timeline โ€” Grafton County, NH

Catnip Planting Calendar

Activity When Date Range
Transplant Outdoors May 19 May 19 โ€“ Jun 2
Harvest July 21 Jul 21 โ€“ Sep 22

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June Transplant Outdoors
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

60โ€“80 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 4b

Growing Season

148 days

Growing Tips for Grafton County

Direct sow or start indoors. Catnip is very easy to grow and can become invasive. Harvest leaves before flowering for tea. Protect young plants from cats.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Catnip in Grafton County, NH?

Grafton County is in Zone 4b with an average last frost of May 12. Plan your Catnip planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Grafton County, NH?

Grafton County, New Hampshire is in USDA Hardiness Zone 4b. The average last spring frost is May 12 and first fall frost is October 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Grafton County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Grafton County, NH. Local conditions may vary. Last updated: April 2026.