Blog

When to Plant Rutabaga in Merrimack County, NH

Merrimack County, New Hampshire Zone 5b May

May in the garden — Merrimack County, New Hampshire

Welcome to May in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 7
Avg. first frost October 10
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.5 hrs

Instant PDF download. No spam, unsubscribe any time.

Rutabagas are a cross between turnips and cabbage, producing large yellow-fleshed roots with a sweet, mild flavor. They are excellent mashed, roasted, or in stews.

Merrimack County, New Hampshire is in USDA Zone 5b. The average last spring frost is May 7 and the first fall frost is October 10, giving you a growing season of approximately 156 days.

At an elevation of 836 feet, Merrimack County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Rutabaga during the growing season.

Merrimack County, NH (Zone 5b) Moderate season
156 days
Last Spring Frost May 7
156 growing days
First Fall Frost October 10

Merrimack County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Transplant: May 1 🍅 Harvest: Jul 24 – Aug 28
Recommended (50%) ✓ Fits season (37 days to spare)
Transplant: May 7 🍅 Harvest: Jul 30 – Sep 3
Safe Start (90%) ✓ Fits season (40 days to spare)
Transplant: May 17 🍅 Harvest: Aug 9 – Sep 13

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 Merrimack County

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

Soil pH

Your soil pH (4.9–6.7) is more acidic than Rutabaga prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Rutabaga.

How to Plant Rutabaga

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Rutabaga

2
successive plantings in your 156-day season

Sow every 9.1 weeks. Last sowing by Jul 02 to harvest before frost.

For a dedicated fall crop, sow by Aug 01.

Plant Water Budget

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

Monthly Watering Guide for Rutabaga

Rutabaga needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Rutabaga Needs Rainfall You Supplement Action
Jan 2.9" 0" ❄️ Dormant
Feb 3.1" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 3" 3.4" 0" ✅ Rainfall sufficient
Jun 3" 3.9" 0" ✅ Rainfall sufficient
Jul 3" 4.1" 0" ✅ Rainfall sufficient
Aug 3" 3.6" 0" ✅ Rainfall sufficient
Sep 3" 3.2" 0" ✅ Rainfall sufficient
Oct 3" 3.2" 0" ✅ Rainfall sufficient
Nov 2.7" 0" ❄️ Dormant
Dec 3.3" 0" ❄️ Dormant

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

Rutabaga 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.

Rutabaga needs ~1,305 GDD — county provides 2,262 GDD Excellent fit

Rutabaga Planting Timeline — Merrimack County, NH

Rutabaga Planting Calendar

Activity When Date Range
Direct Sow April 23 Apr 23 – May 14
Harvest July 16 Jul 16 – Aug 20
Fall Sowing August 1 Aug 1 – Aug 15

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Direct Sow
May Direct Sow
June
July Harvest
August Fall Sowing Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5b

📆 Growing Season

156 days in Merrimack County

Growing Tips for Rutabaga in Merrimack County

Direct sow Rutabaga outdoors after May 07 in Merrimack County when soil has warmed and frost danger has passed.

Common pests for Rutabaga in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in early summer for fall harvest. Thin seedlings to 6-8 inches apart. Flavor improves significantly after a few light frosts.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rutabaga in Merrimack County, NH?

Merrimack County is in Zone 5b with an average last frost of May 7. Plan your Rutabaga planting based on this frost date — see the calendar above for exact timing.

What planting zone is Merrimack County, NH?

Merrimack County, New Hampshire is in USDA Hardiness Zone 5b. The average last spring frost is May 7 and first fall frost is October 10.

🌱

Your Merrimack County Garden Planner — Free

A 24-page printable planner built for Merrimack County (Zone 5b). 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 Merrimack County, NH. 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.