When to Plant Sweet Potatoes in Plumas County, CA
Your May gardening checklist
We've pulled the most time-sensitive tasks for Plumas County, California this May and put them front and centre. Tackle them in order.
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Seed sweet potatoes outdoors
Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.
June prep starts now
- Transplants going out: sweet potatoes
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.
Plumas County, California is in USDA Zone 7b. The average last spring frost is May 20 and the first fall frost is October 8, giving you a growing season of approximately 141 days.
At an elevation of 1,185 feet, Plumas County receives approximately 30.9 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Sweet Potatoes to ensure they mature before fall.
Plumas County Soil Profile
Soil Type
Loam
Soil pH
6.6-7.6
Drainage
Well Drained
Plant Planting Risk Windows
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 Plumas County
How your county's soil matches Sweet Potatoes's growing requirements.
Soil pH
Your soil pH (6.6–7.6) 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 Plumas 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
Plant Water Budget
Water stress score is 8/10 — 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 | — | 6.9" | 0" | ❄️ Dormant |
| Feb | — | 6.2" | 0" | ❄️ Dormant |
| Mar | — | 5" | 0" | ❄️ Dormant |
| Apr | — | 2.4" | 0" | ❄️ Dormant |
| May | 4.3" | 1" | 3.3" | 🚿 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" | 0.3" | 4" | 🚿 Regular watering |
| Oct | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Nov | — | 3" | 0" | ❄️ Dormant |
| Dec | — | 4.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Plumas 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 Planting Timeline — Plumas County, CA
Sweet Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 1 | Apr 1 – Apr 15 |
| Transplant Outdoors | June 3 | Jun 3 – Jun 17 |
| Direct Sow | May 27 | May 27 – Jun 17 |
| Harvest | September 2 | Sep 2 – Oct 21 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| 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 7b
📆 Growing Season
141 days in Plumas County
Growing Tips for Sweet Potatoes in Plumas County
Direct sow Sweet Potatoes outdoors after May 20 in Plumas 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
Check more plant combinations with our Companion Planting Checker →
Sweet Potatoes in Other Locations
Frequently Asked Questions
When should I plant Sweet Potatoes in Plumas County, CA?
Plumas County is in Zone 7b with an average last frost of May 20. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Plumas County, CA?
Plumas County, California is in USDA Hardiness Zone 7b. The average last spring frost is May 20 and first fall frost is October 8.
Your Plumas County Garden Planner — Free
A 24-page printable planner built for Plumas County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.