When to Plant Sunchoke in Hillsborough County, NH
What to do in May
Your garden in Hillsborough County, New Hampshire is working on a schedule, even when you're not. Here's where you should be this May.
-
Move sunchoke into the garden
Your last frost (May 2) has passed. These warm-season crops can handle outdoor soil now.
Sunchokes (Jerusalem artichokes) are a native sunflower relative grown for their knobby, nutty-flavored tubers. They are extremely productive and nearly impossible to eradicate.
Hillsborough County, New Hampshire is in USDA Zone 6a. The average last spring frost is May 2 and the first fall frost is October 11, giving you a growing season of approximately 162 days.
At an elevation of 145 feet, Hillsborough County receives approximately 44 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Sunchoke to ensure they mature before fall.
Hillsborough County Soil Profile
Soil Type
Silt Loam
Soil pH
4.9-6.6
Drainage
Well Drained
Plant Planting Risk Windows
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 Hillsborough County
How your county's soil matches Sunchoke's growing requirements.
Soil pH
Your soil pH (4.9–6.6) is more acidic than Sunchoke prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Hillsborough County is excellent for Sunchoke — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Sunchoke.
Organic Matter
Organic matter is moderate (3.9%). Annual compost additions will help Sunchoke.
How to Plant Sunchoke
Plant Water Budget
Monthly Watering Guide for Sunchoke
Sunchoke needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Sunchoke Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3" | 0" | ❄️ Dormant |
| Feb | — | 2.7" | 0" | ❄️ Dormant |
| Mar | — | 3.8" | 0" | ❄️ Dormant |
| Apr | — | 4.4" | 0" | ❄️ Dormant |
| May | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jun | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jul | 4.3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Sep | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Oct | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Nov | — | 3.2" | 0" | ❄️ Dormant |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Hillsborough County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sunchoke 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.
Sunchoke Planting Timeline — Hillsborough County, NH
Sunchoke Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 16 | May 16 – May 30 |
| Harvest | September 5 | Sep 5 – Oct 31 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
110–150 days
🧪 Soil pH
Needs 6–7.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6a
📆 Growing Season
162 days in Hillsborough County
Growing Tips for Sunchoke in Hillsborough County
Direct sow Sunchoke outdoors after May 02 in Hillsborough County when soil has warmed and frost danger has passed.
Your 162.0-day growing season in Hillsborough County is tight for Sunchoke (110.0-150.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Sunchoke in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Plant tubers 4 inches deep in early spring. Contain plants with barriers as they spread aggressively. Harvest after frost or leave in ground and dig as needed through winter.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Sunchoke in Other Locations
Frequently Asked Questions
When should I plant Sunchoke in Hillsborough County, NH?
Hillsborough County is in Zone 6a with an average last frost of May 2. Plan your Sunchoke planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hillsborough County, NH?
Hillsborough County, New Hampshire is in USDA Hardiness Zone 6a. The average last spring frost is May 2 and first fall frost is October 11.
Your Hillsborough County Garden Planner — Free
A 24-page printable planner built for Hillsborough County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.