Blog

When to plant Potatoes in Proberta, CA

Spring Potatoes in Proberta goes in March 6–March 27, once nighttime temps stop dipping near freezing.

When to Plant Potatoes in Proberta, CA

Potatoes
Tehama County, California Zone 9b July

Your July planting checklist for Tehama County, California

Welcome to July in Zone 9b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 6
Avg. first frost November 28
Soil temp (4") 89°F
Watering Critical
Pest pressure High
Daylight 14.6 hrs
  1. Basket week: potatoes

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Instant PDF download. No spam, unsubscribe any time.

Potatoes are a versatile staple crop that produces tubers underground. They come in hundreds of varieties with varying colors, textures, and maturity dates.

Proberta, California is in USDA Zone 9b. The average last spring frost is March 6 and the first fall frost is November 28, giving you a growing season of approximately 267 days.

At an elevation of 78 feet, Tehama County receives approximately 44 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Potatoes to ensure they mature before fall.

Proberta, CA (Zone 9b) Long season
267 days
Last Spring Frost March 6
267 growing days
First Fall Frost November 28

Proberta Soil Profile

Soil Type

Loam

Soil pH

6.8-7.6

Drainage

Well Drained

Potatoes Planting Risk Windows

Early Start (70% safe) ✓ Fits season (123 days to spare)
Start indoors: Jan 12 Transplant: Mar 2 🍅 Harvest: May 11 – Jul 20
Recommended (50%) ✓ Fits season (120 days to spare)
Start indoors: Jan 23 Transplant: Mar 13 🍅 Harvest: May 22 – Jul 31
Safe Start (90%) ✓ Fits season (98 days to spare)
Start indoors: Mar 7 Transplant: Apr 25 🍅 Harvest: Jul 4 – Sep 12

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 Proberta

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

Soil pH

Your soil pH (6.8–7.6) is more alkaline than Potatoes prefers (5.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Tehama County is excellent for Potatoes — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Potatoes.

How to Plant Potatoes

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Potatoes

4
successive plantings in your 267-day season

Sow every 8 weeks. Last sowing by Jul 31 to harvest before frost.

Potatoes Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 878 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Potatoes

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 Potatoes Needs Rainfall You Supplement Action
Jan 10.2" 0" ❄️ Dormant
Feb 8.5" 0" ❄️ Dormant
Mar 4.3" 7" 0" ✅ Rainfall sufficient
Apr 4.3" 3.5" 0.8" 💧 Light watering
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" 0.4" 3.9" 🚿 Regular watering
Oct 4.3" 1.8" 2.5" 🚿 Regular watering
Nov 4.3" 4.2" 0.1" 💧 Light watering
Dec 6.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Tehama County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

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.

Potatoes needs ~1,092 GDD — county provides 3,070 GDD Excellent fit

Potatoes Planting Timeline — Proberta, CA

Potatoes Planting Calendar

Activity When Date Range
Start Indoors January 23 Jan 23 – Feb 6
Transplant Outdoors March 13 Mar 13 – Mar 27
Direct Sow March 6 Mar 6 – Mar 27
Harvest May 22 May 22 – Jul 31

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

70–120 days

🧪 Soil pH

Needs 5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

267 days in Tehama County

Growing Tips for Potatoes in Proberta

Direct sow Potatoes outdoors after March 06 in Tehama County when soil has warmed and frost danger has passed.

Common pests for Potatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant seed potatoes (not grocery store potatoes) 4 inches deep in spring. Hill soil around stems as plants grow to prevent greening. Stop watering when plants die back.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Cucumber
  • Squash Summer

Check more plant combinations with our Companion Planting Checker →

When should I plant Potatoes in Proberta, CA?

In Proberta, CA, plant Potatoes after the last frost (around March 6) and before the first frost (around November 28). Best results when soil holds above 50°F.

What growing zone is Proberta, CA for Potatoes?

Proberta sits in USDA Zone 9b. Potatoes grows reliably in zones 3a through 10b, so it's a good fit here.

Can Potatoes grow in Proberta's climate?

Yes — Potatoes grows well in Proberta's temperate climate. Proberta averages a 267-day frost-free season, with last frost around March 6 and first frost around November 28.

🌱

Your Tehama County Garden Planner — Free

A 22-page printable planner built for Tehama 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Tehama County, CA. Local conditions may vary. Last updated: July 2026.