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When to plant Rhubarb in Cook County, IL

Plant Rhubarb in Cook County, between May 14 and May 28 — the only viable window. Zone 6a's short season (177 frost-free days) rules out a fall crop.

When to Plant Rhubarb in Cook County, IL

Rhubarb is a long-lived perennial vegetable grown for its tart, colorful stalks. Only the stalks are edible as the leaves contain toxic oxalic acid.

Cook County, Illinois is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 17, giving you a growing season of approximately 177 days.

At an elevation of 728 feet, Cook County receives approximately 35.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Rhubarb during the growing season.

Cook County, IL (Zone 6a) Moderate season
177 days
Last Spring Frost April 23
177 growing days
First Fall Frost October 17

Cook County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Rhubarb Planting Timeline — Cook County, IL

Rhubarb Planting Calendar

Activity When Date Range
Transplant Outdoors May 14 May 14 – May 28

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6a

📆 Growing Season

177 days in Cook County

Growing Tips for Cook County

Plant crowns in early spring in rich, well-drained soil. Do not harvest stalks the first year. Pull (do not cut) stalks at harvest to avoid introducing rot.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rhubarb in Cook County, IL?

Cook County is in Zone 6a with an average last frost of April 23. Plan your Rhubarb planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cook County, IL?

Cook County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 23 and first fall frost is October 17.

When should I plant Rhubarb in Cook County, IL?

In Cook County, IL, plant Rhubarb after the last frost (around April 23) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Cook County, IL for Rhubarb?

Cook County sits in USDA Zone 6a. Rhubarb grows reliably in zones 3a through 8b, so it's a good fit here.

Can Rhubarb grow in Cook County's climate?

Yes — Rhubarb grows well in Cook County's temperate climate. Cook County averages a 177-day frost-free season, with last frost around April 23 and first frost around October 17.

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Your Cook County Garden Planner — Free

A 22-page printable planner built for Cook County (Zone 6a). 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 Cook County, IL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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