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When to Plant Catnip in Hamilton County, TN

Hamilton County, Tennessee Zone 8a May

Hamilton County, Tennessee gardeners: here's your May plan

We've pulled the most time-sensitive tasks for Hamilton County, Tennessee this May and put them front and centre. Tackle them in order.

Avg. last frost March 28
Avg. first frost November 1
Soil temp (4") 59°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
A few tasks this May that'll pay off in June
  • First harvests: catnip

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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.

Hamilton County, Tennessee is in USDA Zone 8a. The average last spring frost is March 28 and the first fall frost is November 1, giving you a growing season of approximately 218 days.

At an elevation of 3,918 feet, Hamilton County receives approximately 51.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Catnip during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Catnip root diseases.

Hamilton County, TN (Zone 8a) Long season
218 days
Last Spring Frost March 28
218 growing days
First Fall Frost November 1

Hamilton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (88 days to spare)
Transplant: Mar 28 🍅 Harvest: May 30 – Aug 1
Recommended (50%) ✓ Fits season (85 days to spare)
Transplant: Apr 4 🍅 Harvest: Jun 6 – Aug 8
Safe Start (90%) ✓ Fits season (85 days to spare)
Transplant: Apr 24 🍅 Harvest: Jun 26 – Aug 28

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.

Soil Compatibility in Hamilton County

How your county's soil matches Catnip's growing requirements.

Soil pH

Your soil pH (5.6–6.9) overlaps with Catnip's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Hamilton County is excellent for Catnip — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Catnip.

How to Plant Catnip

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Catnip

4
successive plantings in your 218-day season

Sow every 6.9 weeks. Last sowing by Aug 13 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Catnip

Catnip needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Catnip Needs Rainfall You Supplement Action
Jan 4.3" 0" ❄️ Dormant
Feb 4.5" 0" ❄️ Dormant
Mar 2.2" 4.8" 0" ✅ Rainfall sufficient
Apr 2.2" 4" 0" ✅ Rainfall sufficient
May 2.2" 4.3" 0" ✅ Rainfall sufficient
Jun 2.2" 4.6" 0" ✅ Rainfall sufficient
Jul 2.2" 5.4" 0" ✅ Rainfall sufficient
Aug 2.2" 5.2" 0" ✅ Rainfall sufficient
Sep 2.2" 3.8" 0" ✅ Rainfall sufficient
Oct 2.2" 2.7" 0" ✅ Rainfall sufficient
Nov 2.2" 4.2" 0" ✅ Rainfall sufficient
Dec 3.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Hamilton County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Catnip Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Catnip needs ~1,382 GDD — county provides 4,305 GDD Excellent fit

Catnip Planting Timeline — Hamilton County, TN

Catnip Planting Calendar

Activity When Date Range
Transplant Outdoors April 4 Apr 4 – Apr 18
Harvest June 6 Jun 6 – Aug 8

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

218 days in Hamilton County

Growing Tips for Catnip in Hamilton County

Direct sow Catnip outdoors after March 28 in Hamilton County when soil has warmed and frost danger has passed.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Catnip in Hamilton County, TN?

Hamilton County is in Zone 8a with an average last frost of March 28. Plan your Catnip planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamilton County, TN?

Hamilton County, Tennessee is in USDA Hardiness Zone 8a. The average last spring frost is March 28 and first fall frost is November 1.

🌱

Your Hamilton County Garden Planner — Free

A 24-page printable planner built for Hamilton County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.