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When to Plant Spinach in Vermilion County, IL

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.

Vermilion County, Illinois is in USDA Zone 5b. The average last spring frost is April 14 and the first fall frost is October 16, giving you a growing season of approximately 185 days.

At an elevation of 1,218 feet, Vermilion County receives approximately 31.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Spinach during the growing season.

Vermilion County, IL (Zone 5b) Moderate season
185 days
Last Spring Frost April 14
185 growing days
First Fall Frost October 16

Vermilion County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (85 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: May 16 – Jul 18
Recommended (50%) ✓ Fits season (87 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: May 19 – Jul 21
Safe Start (90%) ✓ Fits season (82 days to spare)
Start indoors: Mar 29 Transplant: May 3 🍅 Harvest: Jun 7 – Aug 9

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.

Plant 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 576 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Spinach needs ~584 GDD — county provides 2,543 GDD Excellent fit

Spinach Planting Timeline โ€” Vermilion County, IL

Spinach Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 โ€“ Mar 24
Transplant Outdoors April 14 Apr 14 โ€“ Apr 28
Direct Sow March 31 Mar 31 โ€“ Apr 21
Fall Sowing August 7 Aug 7 โ€“ Aug 21
Harvest May 19 May 19 โ€“ Jul 21

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

35โ€“50 days

Soil pH

6.5 โ€“ 7.5

USDA Zone

Zone 5b

Growing Season

185 days

Growing Tips for Vermilion 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

Level Up Your Garden

๐ŸŒพ 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 35ยฐF, under 45% humidity.

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

Frequently Asked Questions

When should I plant Spinach in Vermilion County, IL?

Vermilion County is in Zone 5b with an average last frost of April 14. Plan your Spinach planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Vermilion County, IL?

Vermilion County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 14 and first fall frost is October 16.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Vermilion County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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