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When to plant Spinach in Putnam County, IL

Aim to plant Spinach in Putnam County on or after April 7; the window stays open through April 28. Putnam County's 175-day frost-free season gives you a single solid spring crop with a brief fall option. A second sowing from August 4 to August 18 extends the harvest into fall.

When to Plant Spinach in Putnam County, IL

Spinach

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.

Putnam County, Illinois is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.

At an elevation of 582 feet, Putnam County receives approximately 41.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Spinach during the growing season.

Putnam County, IL (Zone 5b) Moderate season
175 days
Last Spring Frost April 21
175 growing days
First Fall Frost October 13

Putnam County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.7

Drainage

Well Drained

Monthly Watering Guide for Spinach

Spinach needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Spinach Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 3.1" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 5.2" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

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

Spinach Planting Timeline — Putnam County, IL

Spinach Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 7 Apr 7 – Apr 28
Harvest May 26 May 26 – Jul 28
Fall Sowing August 4 Aug 4 – Aug 18

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

175 days in Putnam County

Growing Tips for Putnam County

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.

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.

Frequently Asked Questions

When should I plant Spinach in Putnam County, IL?

Putnam County is in Zone 5b with an average last frost of April 21. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is Putnam County, IL?

Putnam County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 13.

When should I plant Spinach in Putnam County, IL?

In Putnam County, IL, plant Spinach after the last frost (around April 21) and before the first frost (around October 13). Best results when soil holds above 50°F.

What growing zone is Putnam County, IL for Spinach?

Putnam County sits in USDA Zone 5b. Spinach grows reliably in zones 2a through 10b, so it's a good fit here.

Can Spinach grow in Putnam County's climate?

Yes — Spinach grows well in Putnam County's temperate climate. Putnam County averages a 175-day frost-free season, with last frost around April 21 and first frost around October 13.

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Your Putnam County Garden Planner — Free

A 22-page printable planner built for Putnam County (Zone 5b). 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 Putnam County, IL. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.