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When to Plant Sweet Potatoes in Montrose County, CO

Montrose County, Colorado Zone 6b May

Your May game plan for Montrose County, Colorado

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost June 13
Avg. first frost September 12
Soil temp (4") 45°F
Watering High
Pest pressure Low
Daylight 14.1 hrs
Coming up in June — start thinking about
  • Transplants going out: sweet potatoes
  • Direct-sowing: 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.

Montrose County, Colorado is in USDA Zone 6b. The average last spring frost is June 13 and the first fall frost is September 12, giving you a growing season of approximately 91 days.

At an elevation of 6,494 feet, Montrose County receives approximately 18.4 inches of rainfall annually with predominantly loam soil. Summer highs average 87°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.

Montrose County, CO (Zone 6b) Very short season
91 days
Last Spring Frost June 13
91 growing days
First Fall Frost September 12
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Montrose County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 19 Transplant: May 28 🍅 Harvest: Aug 27 – Oct 15
Recommended (50%) ✗ May not fit
Start indoors: Apr 18 Transplant: Jun 27 🍅 Harvest: Sep 26 – Nov 14
Safe Start (90%) ✗ May not fit
Start indoors: May 1 Transplant: Jul 10 🍅 Harvest: Oct 9 – Nov 27

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 Montrose County

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

Soil pH

Your soil pH (6.7–7.9) 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 Montrose 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
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 147 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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 2.3" 0" ❄️ Dormant
Jun 4.3" 1.2" 3.1" 🚿 Regular watering
Jul 4.3" 1.8" 2.5" 🚿 Regular watering
Aug 4.3" 1.7" 2.6" 🚿 Regular watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Montrose 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 ~1,601 GDD — county provides 1,387 GDD May not mature

Sweet Potatoes Planting Timeline — Montrose County, CO

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors April 18 Apr 18 – May 2
Transplant Outdoors June 27 Jun 27 – Jul 11
Direct Sow June 20 Jun 20 – Jul 11
Harvest September 26 Sep 26 – Nov 14

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

91 days in Montrose County

Growing Tips for Sweet Potatoes in Montrose County

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

Your 91.0-day growing season in Montrose County is tight for Sweet Potatoes (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Montrose County receives only 18" 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 Montrose County, CO?

Montrose County is in Zone 6b with an average last frost of June 13. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Montrose County, CO?

Montrose County, Colorado is in USDA Hardiness Zone 6b. The average last spring frost is June 13 and first fall frost is September 12.

🌱

Your Montrose County Garden Planner — Free

A 24-page printable planner built for Montrose 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 Montrose 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.