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When to plant Spinach in Isleton,

For Isleton, gardeners: plant Spinach January 22 through February 12 once soil reads 50°F. A second sowing from October 6 to October 20 extends the harvest into fall.

When to Plant Spinach in Isleton, CA

Spinach
Isleton, CA Zone 9b June

This month in Isleton, CA

Your garden in Isleton, CA is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost February 12
Avg. first frost December 1
Soil temp (4") 87°F
Watering Critical
Pest pressure High
Daylight 14.7 hrs

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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.

Isleton, California is in USDA Zone 9b. The average last spring frost is February 12 and the first fall frost is December 1, giving you a growing season of approximately 292 days.

At an elevation of 263 feet, Sacramento County receives approximately 33.2 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Spinach during the growing season.

Isleton, CA (Zone 9b) Year-round
292 days
Last Spring Frost February 12
292 growing days
First Fall Frost December 1
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Isleton Soil Profile

Soil Type

Loam

Soil pH

6.4-7.1

Drainage

Well Drained

Spinach Planting Risk Windows

Early Start (70% safe) ✓ Fits season (205 days to spare)
Start indoors: Dec 29 Transplant: Jan 26 🍅 Harvest: Mar 2 – May 4
Recommended (50%) ✓ Fits season (194 days to spare)
Start indoors: Jan 15 Transplant: Feb 12 🍅 Harvest: Mar 19 – May 21
Safe Start (90%) ✓ Fits season (160 days to spare)
Start indoors: Mar 9 Transplant: Apr 6 🍅 Harvest: May 11 – Jul 13

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 Isleton

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

Soil pH

Your soil pH (6.4–7.1) overlaps with Spinach's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). 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

10
successive plantings in your 292-day season

Sow every 4 weeks. Last sowing by Oct 12 to harvest before frost.

For a dedicated fall crop, sow by Oct 06.

Spinach Water Budget

Plant needs
0.7″/week
Rainfall provides
0.5″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 701 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 6.1" 0" ❄️ Dormant
Feb 3" 7.5" 0" ✅ Rainfall sufficient
Mar 3" 5.7" 0" ✅ Rainfall sufficient
Apr 3" 2.5" 0.5" 💧 Light watering
May 3" 0.8" 2.2" 🚿 Regular watering
Jun 3" 0.2" 2.8" 🚿 Regular watering
Jul 3" 0" 3" 🚿 Regular watering
Aug 3" 0" 3" 🚿 Regular watering
Sep 3" 0.3" 2.7" 🚿 Regular watering
Oct 3" 1.4" 1.6" 🚿 Regular watering
Nov 3" 2.7" 0.3" 💧 Light watering
Dec 3" 5.9" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Sacramento 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 ~744 GDD — county provides 5,127 GDD Excellent fit

Spinach Planting Timeline — Isleton, CA

Spinach Planting Calendar

Activity When Date Range
Start Indoors January 15 Jan 15 – Jan 29
Transplant Outdoors February 12 Feb 12 – Feb 26
Direct Sow January 22 Jan 22 – Feb 12
Harvest March 19 Mar 19 – May 21
Fall Sowing October 6 Oct 6 – Oct 20

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

Month-by-Month Timeline

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

292 days in Sacramento County

Growing Tips for Spinach in Isleton

Direct sow Spinach outdoors after February 12 in Sacramento County when soil has warmed and frost danger has passed.

Your generous 293.0-day season in Sacramento 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 Isleton

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 Isleton, ?

In Isleton, , plant Spinach after the last frost (around February 12) and before the first frost (around December 1). Best results when soil holds above 50°F.

What growing zone is Isleton, for Spinach?

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

Can Spinach grow in Isleton's climate?

Yes — Spinach grows well in Isleton's temperate climate. Isleton averages a 293-day frost-free season, with last frost around February 12 and first frost around December 1.

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Your Sacramento County Garden Planner — Free

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