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When to Plant Sweet Potatoes in Hamilton County, KS

Hamilton County, Kansas Zone 6a May

Your May game plan for Hamilton County, Kansas

May is a pivotal month for Hamilton County, Kansas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 27
Avg. first frost October 12
Soil temp (4") 64°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
  1. Plant out sweet potatoes

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Seed sweet potatoes outdoors

    Your soil is 64°F — warm enough for these to germinate without babying.

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.

Hamilton County, Kansas is in USDA Zone 6a. The average last spring frost is April 27 and the first fall frost is October 12, giving you a growing season of approximately 168 days.

At an elevation of 871 feet, Hamilton County receives approximately 24 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Sweet Potatoes during the growing season.

Hamilton County, KS (Zone 6a) Moderate season
168 days
Last Spring Frost April 27
168 growing days
First Fall Frost October 12

Hamilton County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Feb 24 Transplant: May 5 🍅 Harvest: Aug 4 – Sep 22
Recommended (50%) ✓ Fits season (14 days to spare)
Start indoors: Mar 2 Transplant: May 11 🍅 Harvest: Aug 10 – Sep 28
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: Mar 17 Transplant: May 26 🍅 Harvest: Aug 25 – Oct 13

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 Hamilton County

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

Soil pH

Your soil pH (6.3–7.8) 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 Hamilton 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
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 718 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 1.6" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 3" 1.3" 💧 Light watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2.1" 2.2" 🚿 Regular watering
Aug 4.3" 2.6" 1.7" 💧 Light watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 4.3" 2" 2.3" 🚿 Regular watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hamilton 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 ~1,995 GDD — county provides 3,192 GDD Excellent fit

Sweet Potatoes Planting Timeline — Hamilton County, KS

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors May 11 May 11 – May 25
Direct Sow May 4 May 4 – May 25
Harvest August 10 Aug 10 – Sep 28

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
July
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 6a

📆 Growing Season

168 days in Hamilton County

Growing Tips for Sweet Potatoes in Hamilton County

Direct sow Sweet Potatoes outdoors after April 27 in Hamilton County when soil has warmed and frost danger has passed.

Hamilton 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 Hamilton County, KS?

Hamilton County is in Zone 6a with an average last frost of April 27. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamilton County, KS?

Hamilton County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 27 and first fall frost is October 12.

🌱

Your Hamilton County Garden Planner — Free

A 24-page printable planner built for Hamilton 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.

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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 Hamilton 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.