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When to Plant Sorrel in Iroquois County, IL

Iroquois County, Illinois Zone 5b May

May in the garden — Iroquois County, Illinois

May is a pivotal month for Iroquois County, Illinois gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 18
Avg. first frost October 13
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Fire up the seed-starting tray: sorrel

    These need a head start before your last frost (April 18). Sow into cells now so you're ready to transplant in a few weeks.

  2. Collect sorrel at their peak

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Get ahead of June
  • First harvests: sorrel

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Sorrel is a perennial herb with tangy, lemon-flavored arrow-shaped leaves. It is one of the first greens to emerge in spring and is used in soups and salads.

Iroquois County, Illinois is in USDA Zone 5b. The average last spring frost is April 18 and the first fall frost is October 13, giving you a growing season of approximately 178 days.

At an elevation of 1,345 feet, Iroquois County receives approximately 30 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Sorrel during the growing season.

Iroquois County, IL (Zone 5b) Moderate season
178 days
Last Spring Frost April 18
178 growing days
First Fall Frost October 13

Iroquois County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (80 days to spare)
Start indoors: Mar 9 Transplant: Apr 6 🍅 Harvest: May 18 – Jul 20
Recommended (50%) ✓ Fits season (80 days to spare)
Start indoors: Mar 14 Transplant: Apr 11 🍅 Harvest: May 23 – Jul 25
Safe Start (90%) ✓ Fits season (78 days to spare)
Start indoors: Apr 1 Transplant: Apr 29 🍅 Harvest: Jun 10 – Aug 12

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 Iroquois County

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

Soil pH

Your soil pH (5.9–6.7) is within Sorrel's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Iroquois County is excellent for Sorrel — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Sorrel.

Organic Matter

Organic matter is excellent (4.5%) — Sorrel will thrive.

How to Plant Sorrel

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Sorrel

5
successive plantings in your 178-day season

Sow every 4.6 weeks. Last sowing by Aug 14 to harvest before frost.

For a dedicated fall crop, sow by Aug 04.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,126 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Sorrel

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

Month Sorrel Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 3.6" 0.7" 💧 Light watering
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 2.9" 1.4" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.5" 1.8" 💧 Light watering
Nov 2" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

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

Sorrel 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.

Sorrel needs ~688 GDD — county provides 2,447 GDD Excellent fit

Sorrel Planting Timeline — Iroquois County, IL

Sorrel Planting Calendar

Activity When Date Range
Start Indoors March 14 Mar 14 – Mar 28
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow April 4 Apr 4 – Apr 25
Harvest May 23 May 23 – Jul 25
Fall Sowing August 4 Aug 4 – Aug 18

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

178 days in Iroquois County

Growing Tips for Sorrel in Iroquois County

Direct sow Sorrel outdoors after April 18 in Iroquois County when soil has warmed and frost danger has passed.

Your generous 178.0-day season in Iroquois County allows multiple plantings of Sorrel. Sow every 20.0 days for continuous harvest.

General growing tips

Direct sow in early spring or fall. Remove flower stalks promptly to encourage leaf production. Divide clumps every 3-4 years. Young leaves have the best flavor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sorrel in Iroquois County, IL?

Iroquois County is in Zone 5b with an average last frost of April 18. Plan your Sorrel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Iroquois County, IL?

Iroquois County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 18 and first fall frost is October 13.

🌱

Your Iroquois County Garden Planner — Free

A 24-page printable planner built for Iroquois 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.

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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 Iroquois County, IL. Local conditions may vary. Last updated: May 2026.

Sources & credits

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