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When to Plant Sweet Potatoes in Lyon County, KS

Lyon County, Kansas Zone 6b May

May in Lyon County, Kansas — your action list

Welcome to May in Zone 6b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 12
Avg. first frost October 25
Soil temp (4") 62°F
Watering Moderate
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.

Lyon County, Kansas is in USDA Zone 6b. The average last spring frost is April 12 and the first fall frost is October 25, giving you a growing season of approximately 196 days.

At an elevation of 629 feet, Lyon County receives approximately 24 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Sweet Potatoes during the growing season.

Lyon County, KS (Zone 6b) Moderate season
196 days
Last Spring Frost April 12
196 growing days
First Fall Frost October 25

Lyon County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Start indoors: Feb 8 Transplant: Apr 19 🍅 Harvest: Jul 19 – Sep 6
Recommended (50%) ✓ Fits season (42 days to spare)
Start indoors: Feb 15 Transplant: Apr 26 🍅 Harvest: Jul 26 – Sep 13
Safe Start (90%) ✓ Fits season (47 days to spare)
Start indoors: Feb 28 Transplant: May 9 🍅 Harvest: Aug 8 – Sep 26

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 Lyon County

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

Soil pH

Your soil pH (6.7–7.3) 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 Lyon County is excellent for Sweet Potatoes — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) — Sweet Potatoes will thrive.

How to Plant Sweet Potatoes

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,017 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 0.7" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 3.2" 1.1" 💧 Light watering
Jun 4.3" 4.4" 0" ✅ Rainfall sufficient
Jul 4.3" 2.8" 1.5" 💧 Light watering
Aug 4.3" 2.8" 1.5" 💧 Light watering
Sep 4.3" 2.3" 2" 💧 Light watering
Oct 4.3" 1.7" 2.6" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Lyon 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 ~1,680 GDD — county provides 3,136 GDD Excellent fit

Sweet Potatoes Planting Timeline — Lyon County, KS

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 15 Feb 15 – Mar 1
Transplant Outdoors April 26 Apr 26 – May 10
Direct Sow April 19 Apr 19 – May 10
Harvest July 26 Jul 26 – Sep 13

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
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

196 days in Lyon County

Growing Tips for Sweet Potatoes in Lyon County

Direct sow Sweet Potatoes outdoors after April 12 in Lyon County when soil has warmed and frost danger has passed.

Lyon County receives only 24" of rain annually. Sweet Potatoes needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Lyon County, KS?

Lyon County is in Zone 6b with an average last frost of April 12. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lyon County, KS?

Lyon County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 12 and first fall frost is October 25.

🌱

Your Lyon County Garden Planner — Free

A 24-page printable planner built for Lyon 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 Lyon 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.