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When to Plant Sweet Potatoes in Otero County, CO

Otero County, Colorado Zone 6a May

May to-do list for Otero County, Colorado

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

Avg. last frost April 26
Avg. first frost October 9
Soil temp (4") 51°F
Watering High
Pest pressure Low
Daylight 14 hrs
  1. Transplant sweet potatoes outside

    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. Outdoor sowing time: sweet potatoes

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

June prep starts now
  • 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.

Otero County, Colorado is in USDA Zone 6a. The average last spring frost is April 26 and the first fall frost is October 9, giving you a growing season of approximately 166 days.

At an elevation of 4,145 feet, Otero County receives approximately 14.2 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Sweet Potatoes during the growing season. With low rainfall, drip irrigation is essential for growing Sweet Potatoes successfully. Mulch heavily to conserve soil moisture.

Otero County, CO (Zone 6a) Moderate season
166 days
Last Spring Frost April 26
166 growing days
First Fall Frost October 9
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Otero County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (12 days to spare)
Start indoors: Feb 25 Transplant: May 6 🍅 Harvest: Aug 5 – Sep 23
Recommended (50%) ✓ Fits season (12 days to spare)
Start indoors: Mar 1 Transplant: May 10 🍅 Harvest: Aug 9 – Sep 27
Safe Start (90%) ✓ Fits season (10 days to spare)
Start indoors: Mar 18 Transplant: May 27 🍅 Harvest: Aug 26 – Oct 14

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 Otero County

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

Soil pH

Your soil pH (6.4–8.1) 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 Otero County is excellent for Sweet Potatoes — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). 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
0.4″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,136 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" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 4.3" 1.4" 2.9" 🚿 Regular watering
May 4.3" 1.5" 2.8" 🚿 Regular watering
Jun 4.3" 1.1" 3.2" 🚿 Regular watering
Jul 4.3" 1.5" 2.8" 🚿 Regular watering
Aug 4.3" 1.3" 3" 🚿 Regular watering
Sep 4.3" 1.1" 3.2" 🚿 Regular watering
Oct 4.3" 1.2" 3.1" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Otero 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 ~1,838 GDD — county provides 2,905 GDD Excellent fit

Sweet Potatoes Planting Timeline — Otero County, CO

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 1 Mar 1 – Mar 15
Transplant Outdoors May 10 May 10 – May 24
Direct Sow May 3 May 3 – May 24
Harvest August 9 Aug 9 – Sep 27

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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 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

166 days in Otero County

Growing Tips for Sweet Potatoes in Otero County

Direct sow Sweet Potatoes outdoors after April 26 in Otero County when soil has warmed and frost danger has passed.

Otero County receives only 14" 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 Otero County, CO?

Otero County is in Zone 6a with an average last frost of April 26. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Otero County, CO?

Otero County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is April 26 and first fall frost is October 9.

🌱

Your Otero County Garden Planner — Free

A 24-page printable planner built for Otero 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 Otero 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.