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When to Plant Sweet Potatoes in Yuma County, CO

Yuma County, Colorado Zone 5b May

What to do in May

We've pulled the most time-sensitive tasks for Yuma County, Colorado this May and put them front and centre. Tackle them in order.

Avg. last frost May 11
Avg. first frost October 5
Soil temp (4") 35°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
  1. Time to transplant sweet potatoes

    Frost risk is low now in Yuma County, Colorado. If you've been covering beds overnight, you can stop.

  2. Direct-sow sweet potatoes

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

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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.

Yuma County, Colorado is in USDA Zone 5b. The average last spring frost is May 11 and the first fall frost is October 5, giving you a growing season of approximately 147 days.

At an elevation of 7,664 feet, Yuma County receives approximately 20.5 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Sweet Potatoes during the growing season.

Yuma County, CO (Zone 5b) Short season
147 days
Last Spring Frost May 11
147 growing days
First Fall Frost October 5

Yuma County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 7 Transplant: May 16 🍅 Harvest: Aug 15 – Oct 3
Recommended (50%) ✗ May not fit
Start indoors: Mar 16 Transplant: May 25 🍅 Harvest: Aug 24 – Oct 12
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 Yuma County

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

Soil pH

Your soil pH (6.6–7.9) 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 Yuma County is excellent for Sweet Potatoes — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). 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
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 650 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 1.5" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 2.3" 2" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 1.9" 2.4" 🚿 Regular watering
Aug 4.3" 2.2" 2.1" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 1.5" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Yuma 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 ~1,444 GDD — county provides 2,021 GDD Excellent fit

Sweet Potatoes Planting Timeline — Yuma County, CO

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors May 25 May 25 – Jun 8
Direct Sow May 18 May 18 – Jun 8
Harvest August 24 Aug 24 – Oct 12

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 Transplant Outdoors Direct Sow
July
August Harvest
September Harvest
October Harvest
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 5b

📆 Growing Season

147 days in Yuma County

Growing Tips for Sweet Potatoes in Yuma County

Direct sow Sweet Potatoes outdoors after May 11 in Yuma County when soil has warmed and frost danger has passed.

Yuma County receives only 20" 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 Yuma County, CO?

Yuma County is in Zone 5b with an average last frost of May 11. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Yuma County, CO?

Yuma County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 11 and first fall frost is October 5.

🌱

Your Yuma County Garden Planner — Free

A 24-page printable planner built for Yuma County (Zone 5b). 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 Yuma County, CO. 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.