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When to Plant Sweet Potatoes in Grant County, NE

Grant County, Nebraska Zone 5a May

May in the garden — Grant County, Nebraska

A quick May briefing for Grant County, Nebraska gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 13
Avg. first frost October 5
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
  1. Move sweet potatoes into the garden

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Seed sweet potatoes outdoors

    Your soil is 54°F — warm enough for these to germinate without babying.

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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.

Grant County, Nebraska is in USDA Zone 5a. The average last spring frost is May 13 and the first fall frost is October 5, giving you a growing season of approximately 145 days.

At an elevation of 689 feet, Grant County receives approximately 24.2 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Sweet Potatoes to ensure they mature before fall.

Grant County, NE (Zone 5a) Short season
145 days
Last Spring Frost May 13
145 growing days
First Fall Frost October 5
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Grant County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 13 Transplant: May 22 🍅 Harvest: Aug 21 – Oct 9
Recommended (50%) ✗ May not fit
Start indoors: Mar 18 Transplant: May 27 🍅 Harvest: Aug 26 – Oct 14
Safe Start (90%) ✗ May not fit
Start indoors: Mar 26 Transplant: Jun 4 🍅 Harvest: Sep 3 – Oct 22

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 Grant County

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

Soil pH

Your soil pH (6.2–7.5) 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 Grant 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 463 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.5" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.7" 0" ❄️ Dormant
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 1.9" 2.4" 🚿 Regular watering
Aug 4.3" 2.3" 2" 💧 Light watering
Sep 4.3" 2.1" 2.2" 🚿 Regular watering
Oct 4.3" 2.5" 1.8" 💧 Light watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Grant 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 ~1,050 GDD — county provides 1,450 GDD Excellent fit

Sweet Potatoes Planting Timeline — Grant County, NE

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors May 27 May 27 – Jun 10
Direct Sow May 20 May 20 – Jun 10
Harvest August 26 Aug 26 – Oct 14

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Harvest
September Harvest
October Harvest
November
December
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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 5a

📆 Growing Season

145 days in Grant County

Growing Tips for Sweet Potatoes in Grant County

Direct sow Sweet Potatoes outdoors after May 13 in Grant County when soil has warmed and frost danger has passed.

Grant 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 Grant County, NE?

Grant County is in Zone 5a with an average last frost of May 13. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grant County, NE?

Grant County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is May 13 and first fall frost is October 5.

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Your Grant County Garden Planner — Free

A 24-page printable planner built for Grant County (Zone 5a). 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 Grant County, NE. 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.