Blog

When to plant Spinach in Jackson, CA

Plant Spinach in Jackson, when soil hits 50°F — usually February 15. Continue planting through March 8 for the spring crop. A second sowing from September 30 to October 14 extends the harvest into fall.

When to Plant Spinach in Jackson, CA

Spinach
Amador County, California Zone 9b June

This month in Amador County, California

A quick June briefing for Amador County, California gardeners — what's urgent, what's next, and what can wait.

Avg. last frost March 8
Avg. first frost November 25
Soil temp (4") 80°F
Watering Critical
Pest pressure High
Daylight 14.7 hrs
  1. Start harvesting spinach

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Instant PDF download. No spam, unsubscribe any time.

Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.

Jackson, California is in USDA Zone 9b. The average last spring frost is March 8 and the first fall frost is November 25, giving you a growing season of approximately 262 days.

At an elevation of 1,335 feet, Amador County receives approximately 42.7 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Spinach during the growing season.

Jackson, CA (Zone 9b) Long season
262 days
Last Spring Frost March 8
262 growing days
First Fall Frost November 25

Jackson Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Spinach Planting Risk Windows

Early Start (70% safe) ✓ Fits season (179 days to spare)
Start indoors: Jan 8 Transplant: Feb 5 🍅 Harvest: Mar 12 – May 14
Recommended (50%) ✓ Fits season (164 days to spare)
Start indoors: Feb 8 Transplant: Mar 8 🍅 Harvest: Apr 12 – Jun 14
Safe Start (90%) ✓ Fits season (146 days to spare)
Start indoors: Mar 22 Transplant: Apr 19 🍅 Harvest: May 24 – Jul 26

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 Jackson

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

Soil pH

Your soil pH (6.7–7.8) overlaps with Spinach's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Spinach.

How to Plant Spinach

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Spinach

9
successive plantings in your 262-day season

Sow every 4 weeks. Last sowing by Oct 06 to harvest before frost.

For a dedicated fall crop, sow by Sep 30.

Spinach Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 43 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Spinach

Spinach needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Spinach Needs Rainfall You Supplement Action
Jan 9.4" 0" ❄️ Dormant
Feb 8" 0" ❄️ Dormant
Mar 3" 6" 0" ✅ Rainfall sufficient
Apr 3" 3.5" 0" ✅ Rainfall sufficient
May 3" 1" 2" 🚿 Regular watering
Jun 3" 0.2" 2.8" 🚿 Regular watering
Jul 3" 0" 3" 🚿 Regular watering
Aug 3" 0" 3" 🚿 Regular watering
Sep 3" 0.5" 2.5" 🚿 Regular watering
Oct 3" 1.9" 1.1" 💧 Light watering
Nov 3" 4.3" 0" ✅ Rainfall sufficient
Dec 7.8" 0" ❄️ Dormant

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

Spinach 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.

Spinach needs ~712 GDD — county provides 4,388 GDD Excellent fit

Spinach Planting Timeline — Jackson, CA

Spinach Planting Calendar

Activity When Date Range
Start Indoors February 8 Feb 8 – Feb 22
Transplant Outdoors March 8 Mar 8 – Mar 22
Direct Sow February 15 Feb 15 – Mar 8
Harvest April 12 Apr 12 – Jun 14
Fall Sowing September 30 Sep 30 – Oct 14

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

262 days in Amador County

Growing Tips for Spinach in Jackson

Direct sow Spinach outdoors after March 08 in Amador County when soil has warmed and frost danger has passed.

Your generous 262.0-day season in Amador County allows multiple plantings of Spinach. Sow every 17.0 days for continuous harvest.

General growing tips

Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.

Recommended Spinach Varieties for Jackson

Slow-bolting spinach for warm springs — best as fall crop here

Bloomsdale Long Standing Tyee Space

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Spinach Seeds
Life Cycle Annual
Pollination Wind Pollinated
How to Collect Let plants bolt. Harvest seed stalks when seeds turn tan.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Wind pollinated — isolate 1/2 mile for purity. Easy to let bolt in heat.

When should I plant Spinach in Jackson, CA?

In Jackson, CA, plant Spinach after the last frost (around March 8) and before the first frost (around November 25). Best results when soil holds above 50°F.

What growing zone is Jackson, CA for Spinach?

Jackson sits in USDA Zone 9b. Spinach grows reliably in zones 2a through 10b, so it's a good fit here.

Can Spinach grow in Jackson's climate?

Yes — Spinach grows well in Jackson's temperate climate. Jackson averages a 262-day frost-free season, with last frost around March 8 and first frost around November 25.

🌱

Your Amador County Garden Planner — Free

A 22-page printable planner built for Amador 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 Amador County, CA. Local conditions may vary. Last updated: June 2026.