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When to plant Catnip in Suffolk County, MA

Plant Catnip in Suffolk County, between May 1 and May 15 — the only viable window. Zone 7a's short season (176 frost-free days) rules out a fall crop.

When to Plant Catnip in Suffolk County, MA

Suffolk County, Massachusetts Zone 7a August

August in the garden — Suffolk County, Massachusetts

Your garden in Suffolk County, Massachusetts is working on a schedule, even when you're not. Here's where you should be this August.

Avg. last frost April 24
Avg. first frost October 17
Soil temp (4") 82°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. Basket week: catnip

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Get ahead of September
  • 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.

Suffolk County, Massachusetts is in USDA Zone 7a. The average last spring frost is April 24 and the first fall frost is October 17, giving you a growing season of approximately 176 days.

At an elevation of 984 feet, Suffolk County receives approximately 45.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Catnip during the growing season.

Suffolk County, MA (Zone 7a) Moderate season
176 days
Last Spring Frost April 24
176 growing days
First Fall Frost October 17

Suffolk County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.3

Drainage

Well Drained

Catnip Planting Risk Windows

Early Start (70% safe) ✓ Fits season (41 days to spare)
Transplant: Apr 27 🍅 Harvest: Jun 29 – Aug 31
Recommended (50%) ✓ Fits season (43 days to spare)
Transplant: May 1 🍅 Harvest: Jul 3 – Sep 4
Safe Start (90%) ✓ Fits season (39 days to spare)
Transplant: May 20 🍅 Harvest: Jul 22 – Sep 23

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 Suffolk County

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

Soil pH

Your soil pH (4.8–6.3) is more acidic than Catnip prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Catnip.

How to Plant Catnip

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

Succession Planting Catnip

3
successive plantings in your 176-day season

Sow every 6.9 weeks. Last sowing by Jul 29 to harvest before frost.

Catnip Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/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 3" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 3.7" 0" ❄️ Dormant
Apr 2.2" 3.9" 0" ✅ Rainfall sufficient
May 2.2" 3.8" 0" ✅ Rainfall sufficient
Jun 2.2" 4.1" 0" ✅ Rainfall sufficient
Jul 2.2" 4.8" 0" ✅ Rainfall sufficient
Aug 2.2" 4.2" 0" ✅ Rainfall sufficient
Sep 2.2" 4.1" 0" ✅ Rainfall sufficient
Oct 2.2" 4" 0" ✅ Rainfall sufficient
Nov 3.7" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Suffolk 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 ~1,172 GDD — county provides 2,948 GDD Excellent fit

Catnip Planting Timeline — Suffolk County, MA

Catnip Planting Calendar

Activity When Date Range
Transplant Outdoors May 1 May 1 – May 15
Harvest July 3 Jul 3 – Sep 4

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July Harvest
August Harvest
September Harvest
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: too_acidic

🗺️ USDA Zone

Zone 7a

📆 Growing Season

176 days in Suffolk County

Growing Tips for Catnip in Suffolk County

Direct sow Catnip outdoors after April 24 in Suffolk 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 Suffolk County, MA?

Suffolk County is in Zone 7a with an average last frost of April 24. Plan your Catnip planting based on this frost date — see the calendar above for exact timing.

What planting zone is Suffolk County, MA?

Suffolk County, Massachusetts is in USDA Hardiness Zone 7a. The average last spring frost is April 24 and first fall frost is October 17.

When should I plant Catnip in Suffolk County, MA?

In Suffolk County, MA, plant Catnip after the last frost (around April 24) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Suffolk County, MA for Catnip?

Suffolk County sits in USDA Zone 7a. Catnip grows reliably in zones 3a through 9b, so it's a good fit here.

Can Catnip grow in Suffolk County's climate?

Yes — Catnip grows well in Suffolk County's temperate climate. Suffolk County averages a 176-day frost-free season, with last frost around April 24 and first frost around October 17.

🌱

Your Suffolk County Garden Planner — Free

A 22-page printable planner built for Suffolk County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Suffolk County, MA. Local conditions may vary. Last updated: August 2026.

Sources & credits

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