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When to Plant Sweet Potatoes in Linn County, KS

Linn County, Kansas Zone 6b May

Linn County, Kansas gardeners: here's your May plan

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 April 9
Avg. first frost October 25
Soil temp (4") 65°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
Coming up in June — start thinking about
  • Starting indoors: sweet potatoes

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Sweet potatoes are a warm-season root crop that produces nutritious, sweet tubers in orange, white, and purple varieties. They need a long, hot growing season.

Linn County, Kansas is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 25, giving you a growing season of approximately 199 days.

At an elevation of 434 feet, Linn County receives approximately 33 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Sweet Potatoes during the growing season.

Linn County, KS (Zone 6b) Moderate season
199 days
Last Spring Frost April 9
199 growing days
First Fall Frost October 25

Linn 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 (42 days to spare)
Start indoors: Feb 7 Transplant: Apr 18 🍅 Harvest: Jul 18 – Sep 5
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Feb 12 Transplant: Apr 23 🍅 Harvest: Jul 23 – Sep 10
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Feb 25 Transplant: May 6 🍅 Harvest: Aug 5 – Sep 23

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 Linn County

How your county's soil matches Sweet Potatoes's growing requirements.

Soil pH

Your soil pH (6.6–7.2) is more alkaline than Sweet Potatoes prefers (5.5–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Linn County is excellent for Sweet Potatoes — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.7%). Annual compost additions will help Sweet Potatoes.

How to Plant Sweet Potatoes

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 645 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Sweet Potatoes

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

Month Sweet Potatoes Needs Rainfall You Supplement Action
Jan 0.9" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 5.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 4.5" 0" ✅ Rainfall sufficient
Sep 4.3" 2.6" 1.7" 💧 Light watering
Oct 4.3" 2.3" 2" 💧 Light watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

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

Sweet Potatoes 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.

Sweet Potatoes needs ~1,522 GDD — county provides 2,885 GDD Excellent fit

Sweet Potatoes Planting Timeline — Linn County, KS

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 12 Feb 12 – Feb 26
Transplant Outdoors April 23 Apr 23 – May 7
Direct Sow April 16 Apr 16 – May 7
Harvest July 23 Jul 23 – Sep 10

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

199 days in Linn County

Growing Tips for Sweet Potatoes in Linn County

Direct sow Sweet Potatoes outdoors after April 09 in Linn County when soil has warmed and frost danger has passed.

General growing tips

Plant slips (rooted sprouts) after soil is thoroughly warm. Build raised mounds for better root development. Cure harvested roots at 80-85F for 10 days to develop sweetness.

Companion Planting

Good Companions

Avoid Planting Near

  • Squash Summer

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Potatoes in Linn County, KS?

Linn County is in Zone 6b with an average last frost of April 9. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Linn County, KS?

Linn County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 25.

🌱

Your Linn County Garden Planner — Free

A 24-page printable planner built for Linn County (Zone 6b). 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 Linn County, KS. 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.