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When to Plant Comfrey in Stanley County, SD

Stanley County, South Dakota Zone 4a April

What to do in April

A quick April briefing for Stanley County, South Dakota gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 10
Avg. first frost October 3
Soil temp (4") 39°F
Watering High
Pest pressure Low
Daylight 13.2 hrs
To set up a strong May, finish these tasks
  • Transplants going out: comfrey

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Comfrey is a vigorous perennial herb valued as a dynamic accumulator of nutrients. Its leaves make excellent mulch, compost activator, and liquid fertilizer.

Stanley County, South Dakota is in USDA Zone 4a. The average last spring frost is May 10 and the first fall frost is October 3, giving you a growing season of approximately 146 days.

At an elevation of 908 feet, Stanley County receives approximately 29.5 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Comfrey to ensure they mature before fall.

Stanley County, SD (Zone 4a) Short season
146 days
Last Spring Frost May 10
146 growing days
First Fall Frost October 3

Stanley County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (7 days to spare)
Transplant: May 11 🍅 Harvest: Jul 13 – Sep 21
Recommended (50%) ✓ Fits season (6 days to spare)
Transplant: May 17 🍅 Harvest: Jul 19 – Sep 27
Safe Start (90%) ✓ Fits season (11 days to spare)
Transplant: May 27 🍅 Harvest: Jul 29 – Oct 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 Stanley County

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

Soil pH

Your soil pH (6.6–7.2) overlaps with Comfrey's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Stanley County is excellent for Comfrey — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Comfrey.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Comfrey.

How to Plant Comfrey

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

Succession Planting Comfrey

2
successive plantings in your 146-day season

Sow every 6.9 weeks. Last sowing by Jul 05 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 704 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Comfrey

Comfrey needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Comfrey Needs Rainfall You Supplement Action
Jan 2.2" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 2.7" 0" ❄️ Dormant
May 4.3" 3.4" 0.9" 💧 Light watering
Jun 4.3" 1.8" 2.5" 🚿 Regular watering
Jul 4.3" 2.5" 1.8" 💧 Light watering
Aug 4.3" 3.1" 1.2" 💧 Light watering
Sep 4.3" 2.5" 1.8" 💧 Light watering
Oct 4.3" 2.3" 2" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

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

Comfrey 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.

Comfrey needs ~919 GDD — county provides 1,788 GDD Excellent fit

Comfrey Planting Timeline — Stanley County, SD

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 17 May 17 – May 31
Harvest July 19 Jul 19 – Sep 27

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

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

146 days in Stanley County

Growing Tips for Comfrey in Stanley County

Direct sow Comfrey outdoors after May 10 in Stanley County when soil has warmed and frost danger has passed.

General growing tips

Plant root cuttings 2 inches deep. Choose Bocking 14 variety to prevent self-seeding. Cut leaves 3-4 times per season for mulch or compost. Avoid planting near pathways as it spreads.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Comfrey in Stanley County, SD?

Stanley County is in Zone 4a with an average last frost of May 10. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stanley County, SD?

Stanley County, South Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 10 and first fall frost is October 3.

🌱

Your Stanley County Garden Planner — Free

A 24-page printable planner built for Stanley County (Zone 4a). 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 Stanley County, SD. Local conditions may vary. Last updated: April 2026.

Sources & credits

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