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When to Plant Sweet Potatoes in Cochise County, AZ

Cochise County, Arizona Zone 8b May

May in the garden — Cochise County, Arizona

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

Avg. last frost March 30
Avg. first frost November 9
Soil temp (4") 65°F
Watering Critical
Pest pressure High
Daylight 13.6 hrs
  1. Indoor seed-starting week for sweet potatoes

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

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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.

Cochise County, Arizona is in USDA Zone 8b. The average last spring frost is March 30 and the first fall frost is November 9, giving you a growing season of approximately 224 days.

At an elevation of 3,447 feet, Cochise County receives approximately 9.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 105°F, so Sweet Potatoes may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Sweet Potatoes will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Sweet Potatoes successfully. Mulch heavily to conserve soil moisture.

Cochise County, AZ (Zone 8b) Long season
224 days
Last Spring Frost March 30
224 growing days
First Fall Frost November 9
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Cochise County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.9-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (84 days to spare)
Start indoors: Jan 17 Transplant: Mar 21 🍅 Harvest: Jun 20 – Aug 8
Recommended (50%) ✓ Fits season (70 days to spare)
Start indoors: Feb 9 Transplant: Apr 13 🍅 Harvest: Jul 13 – Aug 31
Safe Start (90%) ✓ Fits season (69 days to spare)
Start indoors: Mar 6 Transplant: May 8 🍅 Harvest: Aug 7 – Sep 25

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 Cochise County

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

Soil pH

Your soil pH (6.9–8.3) is more alkaline than Sweet Potatoes prefers (5.5–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Cochise County warms quickly in spring but drains fast. Sweet Potatoes will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Sweet Potatoes.

Organic Matter

Organic matter is low (0.8%). Add 2-3 inches of compost before planting 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
0.2″/week
You supply
1.4″/week
Watering frequency 2-3 times/week
Season total 2,688 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 0.6" 0" ❄️ Dormant
Feb 0.5" 0" ❄️ Dormant
Mar 4.3" 0.5" 3.8" 🚿 Regular watering
Apr 4.3" 0.3" 4" 🚿 Regular watering
May 4.3" 0.2" 4.1" 🚿 Regular watering
Jun 4.3" 0.3" 4" 🚿 Regular watering
Jul 4.3" 1.6" 2.7" 🚿 Regular watering
Aug 4.3" 1.8" 2.5" 🚿 Regular watering
Sep 4.3" 1.4" 2.9" 🚿 Regular watering
Oct 4.3" 0.9" 3.4" 🚿 Regular watering
Nov 4.3" 0.5" 3.8" 🚿 Regular watering
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Cochise 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 ~3,019 GDD — county provides 6,440 GDD Excellent fit

Sweet Potatoes Planting Timeline — Cochise County, AZ

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 9 Feb 9 – Feb 23
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow April 6 Apr 6 – Apr 27
Harvest July 13 Jul 13 – Aug 31

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors Direct Sow
May
June
July Harvest
August Harvest
September
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 8b

📆 Growing Season

224 days in Cochise County

Growing Tips for Sweet Potatoes in Cochise County

Direct sow Sweet Potatoes outdoors after March 30 in Cochise County when soil has warmed and frost danger has passed.

Sandy soil in Cochise County dries quickly — mulch Sweet Potatoes with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 105°F in Cochise County, provide afternoon shade for Sweet Potatoes and water deeply in the morning.

Cochise County receives only 9" 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 Cochise County, AZ?

Cochise County is in Zone 8b with an average last frost of March 30. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cochise County, AZ?

Cochise County, Arizona is in USDA Hardiness Zone 8b. The average last spring frost is March 30 and first fall frost is November 9.

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Your Cochise County Garden Planner — Free

A 24-page printable planner built for Cochise County (Zone 8b). 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 Cochise County, AZ. 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.