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When to Plant Sweet Potatoes in El Dorado County, CA

El Dorado County, California Zone 9b May

Your May gardening checklist

Your El Dorado County, California garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 11
Avg. first frost November 22
Soil temp (4") 62°F
Watering Critical
Pest pressure Moderate
Daylight 14.1 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.

El Dorado County, California is in USDA Zone 9b. The average last spring frost is April 11 and the first fall frost is November 22, giving you a growing season of approximately 225 days.

At an elevation of 2,714 feet, El Dorado County receives approximately 41 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Sweet Potatoes to ensure they mature before fall.

El Dorado County, CA (Zone 9b) Long season
225 days
Last Spring Frost April 11
225 growing days
First Fall Frost November 22

El Dorado County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (78 days to spare)
Start indoors: Feb 15 Transplant: Apr 5 🍅 Harvest: Jul 5 – Aug 23
Recommended (50%) ✓ Fits season (78 days to spare)
Start indoors: Feb 28 Transplant: Apr 18 🍅 Harvest: Jul 18 – Sep 5
Safe Start (90%) ✓ Fits season (78 days to spare)
Start indoors: Mar 26 Transplant: May 14 🍅 Harvest: Aug 13 – Oct 1

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 El Dorado County

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

Soil pH

Your soil pH (6.3–7.2) 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 El Dorado County is excellent for Sweet Potatoes — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.9%). 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
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 564 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 7.5" 0" ❄️ Dormant
Feb 9.2" 0" ❄️ Dormant
Mar 7" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 1.1" 3.2" 🚿 Regular watering
Jun 4.3" 0.2" 4.1" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.5" 3.8" 🚿 Regular watering
Oct 4.3" 1.6" 2.7" 🚿 Regular watering
Nov 4.3" 3.8" 0.5" 💧 Light watering
Dec 6.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in El Dorado 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 ~1,286 GDD — county provides 2,756 GDD Excellent fit

Sweet Potatoes Planting Timeline — El Dorado County, CA

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow April 11 Apr 11 – May 2
Harvest July 18 Jul 18 – Sep 5

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

Month-by-Month Timeline

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

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 9b

📆 Growing Season

225 days in El Dorado County

Growing Tips for Sweet Potatoes in El Dorado County

Direct sow Sweet Potatoes outdoors after April 11 in El Dorado County when soil has warmed and frost danger has passed.

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 El Dorado County, CA?

El Dorado County is in Zone 9b with an average last frost of April 11. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is El Dorado County, CA?

El Dorado County, California is in USDA Hardiness Zone 9b. The average last spring frost is April 11 and first fall frost is November 22.

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Your El Dorado County Garden Planner — Free

A 24-page printable planner built for El Dorado County (Zone 9b). 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 El Dorado County, CA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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