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When to Plant Comfrey in Harper County, KS

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

Harper County, Kansas is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 27, giving you a growing season of approximately 201 days.

At an elevation of 745 feet, Harper County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 88ยฐF, providing good warmth for Comfrey during the growing season.

Harper County, KS (Zone 6b) Long season
201 days
Last Spring Frost April 9
201 growing days
First Fall Frost October 27

Harper County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (63 days to spare)
Transplant: Apr 10 🍅 Harvest: Jun 12 – Aug 21
Recommended (50%) ✓ Fits season (61 days to spare)
Transplant: Apr 16 🍅 Harvest: Jun 18 – Aug 27
Safe Start (90%) ✓ Fits season (64 days to spare)
Transplant: Apr 29 🍅 Harvest: Jul 1 – Sep 9

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 Harper County

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

Soil pH

Your soil pH (6.2โ€“7.8) overlaps with Comfrey's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Harper County is excellent for Comfrey โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Comfrey.

Organic Matter

Organic matter is excellent (4.1%) โ€” Comfrey will thrive.

How to Plant Comfrey

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

Succession Planting Comfrey

3
successive plantings in your 201-day season

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,548 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 0.7" 0" โ„๏ธ Dormant
Feb โ€” 1.1" 0" โ„๏ธ Dormant
Mar โ€” 1.6" 0" โ„๏ธ Dormant
Apr 4.3" 2.6" 1.7" ๐Ÿ’ง Light watering
May 4.3" 4.5" 0" โœ… Rainfall sufficient
Jun 4.3" 4.1" 0.2" ๐Ÿ’ง Light watering
Jul 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
Aug 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Sep 4.3" 2.7" 1.6" ๐Ÿ’ง Light watering
Oct 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Nov โ€” 1" 0" โ„๏ธ Dormant
Dec โ€” 0.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Harper County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,200 GDD — county provides 3,216 GDD Excellent fit

Comfrey Planting Timeline โ€” Harper County, KS

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 16 Apr 16 โ€“ Apr 30
Harvest June 18 Jun 18 โ€“ Aug 27

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Transplant Outdoors
May โ€”
June Harvest
July Harvest
August Harvest
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

201 days in Harper County

Growing Tips for Comfrey in Harper County

Direct sow Comfrey outdoors after April 09 in Harper 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 Harper County, KS?

Harper County is in Zone 6b with an average last frost of April 9. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Harper County, KS?

Harper County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 27.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Harper County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Harper County, KS. Local conditions may vary. Last updated: April 2026.