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When to Plant Celtuce in Sullivan County, NH

Sullivan County, New Hampshire Zone 5b May

Your May gardening checklist

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 12
Avg. first frost October 7
Soil temp (4") 59°F
Watering Moderate
Pest pressure Low
Daylight 14.5 hrs
  1. Transplant celtuce outside

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

Looking ahead to June
  • Starting indoors: celtuce

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Celtuce (stem lettuce) is a Chinese vegetable grown for its thick, crunchy stem rather than its leaves. The peeled stem has a mild, cucumber-like flavor.

Sullivan County, New Hampshire is in USDA Zone 5b. 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 495 feet, Sullivan County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Celtuce to ensure they mature before fall.

Sullivan County, NH (Zone 5b) Short season
148 days
Last Spring Frost May 12
148 growing days
First Fall Frost October 7

Sullivan County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (46 days to spare)
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Jul 8 – Aug 19
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jul 14 – Aug 25
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Apr 20 Transplant: May 25 🍅 Harvest: Jul 27 – Sep 7

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 Sullivan County

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

Soil pH

Your soil pH (5.0–6.6) is more acidic than Celtuce prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Celtuce.

How to Plant Celtuce

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Succession Planting Celtuce

2
successive plantings in your 148-day season

Sow every 6.9 weeks. Last sowing by Jul 09 to harvest before frost.

For a dedicated fall crop, sow by Jul 29.

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 Celtuce

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

Month Celtuce Needs Rainfall You Supplement Action
Jan 2.7" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 3.6" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 3" 3.6" 0" ✅ Rainfall sufficient
Jun 3" 3.3" 0" ✅ Rainfall sufficient
Jul 3" 4.3" 0" ✅ Rainfall sufficient
Aug 3" 3.3" 0" ✅ Rainfall sufficient
Sep 3" 3.2" 0" ✅ Rainfall sufficient
Oct 3" 3.1" 0" ✅ Rainfall sufficient
Nov 3" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

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

Celtuce 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.

Celtuce needs ~975 GDD — county provides 1,924 GDD Excellent fit

Celtuce Planting Timeline — Sullivan County, NH

Celtuce Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 – Apr 21
Transplant Outdoors May 12 May 12 – May 26
Direct Sow April 28 Apr 28 – May 19
Harvest July 14 Jul 14 – Aug 25
Fall Sowing July 29 Jul 29 – Aug 12

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Fall Sowing 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

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5b

📆 Growing Season

148 days in Sullivan County

Growing Tips for Celtuce in Sullivan County

Direct sow Celtuce outdoors after May 12 in Sullivan County when soil has warmed and frost danger has passed.

Common pests for Celtuce in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or start indoors. Space 12 inches apart. Harvest when stems are about 1 inch in diameter. Peel the tough outer skin to reveal the tender center.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Celtuce in Sullivan County, NH?

Sullivan County is in Zone 5b with an average last frost of May 12. Plan your Celtuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sullivan County, NH?

Sullivan County, New Hampshire is in USDA Hardiness Zone 5b. The average last spring frost is May 12 and first fall frost is October 7.

🌱

Your Sullivan County Garden Planner — Free

A 24-page printable planner built for Sullivan 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.

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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 Sullivan 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.