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When to plant Chard in St. Clair County, IL

For St. Clair County, gardeners: plant Chard March 19 through April 9 once soil reads 50°F. A second sowing from August 24 to September 7 extends the harvest into fall.

When to Plant Chard in St. Clair County, IL

St. Clair County, Illinois Zone 7a July

What to do in July

Each item below is timed to St. Clair County, Illinois's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 2
Avg. first frost November 2
Soil temp (4") 81°F
Watering Low
Pest pressure High
Daylight 14.4 hrs
  1. Start harvesting chard

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Before August arrives, get these ready
  • Fall sowing: chard

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Swiss chard is a colorful, heat-tolerant green with large crinkled leaves and vibrant stalks in red, yellow, and white. Both the leaves and stems are edible and nutritious.

St. Clair County, Illinois is in USDA Zone 7a. The average last spring frost is April 2 and the first fall frost is November 2, giving you a growing season of approximately 214 days.

At an elevation of 711 feet, St. Clair County receives approximately 34.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Chard during the growing season.

St. Clair County, IL (Zone 7a) Long season
214 days
Last Spring Frost April 2
214 growing days
First Fall Frost November 2

St. Clair County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Chard Planting Risk Windows

Early Start (70% safe) ✓ Fits season (111 days to spare)
Start indoors: Feb 19 Transplant: Mar 26 🍅 Harvest: May 21 – Jul 9
Recommended (50%) ✓ Fits season (109 days to spare)
Start indoors: Feb 26 Transplant: Apr 2 🍅 Harvest: May 28 – Jul 16
Safe Start (90%) ✓ Fits season (115 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: Jun 12 – Jul 31

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 St. Clair County

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

Soil pH

Your soil pH (6.0–7.3) overlaps with Chard's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — Chard will thrive.

How to Plant Chard

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Succession Planting Chard

5
successive plantings in your 214-day season

Sow every 5.7 weeks. Last sowing by Sep 03 to harvest before frost.

For a dedicated fall crop, sow by Aug 24.

Chard Water Budget

Plant needs
0.8″/week
Rainfall provides
0.7″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 299 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Chard

Chard needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Chard Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.5" 3.2" 0.3" 💧 Light watering
May 3.5" 3.8" 0" ✅ Rainfall sufficient
Jun 3.5" 4" 0" ✅ Rainfall sufficient
Jul 3.5" 3.8" 0" ✅ Rainfall sufficient
Aug 3.5" 3.9" 0" ✅ Rainfall sufficient
Sep 3.5" 3.3" 0.2" 💧 Light watering
Oct 3.5" 2.5" 1" 💧 Light watering
Nov 3.5" 2.4" 1.1" 💧 Light watering
Dec 1.8" 0" ❄️ Dormant

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

Chard 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.

Chard needs ~921 GDD — county provides 3,584 GDD Excellent fit

Chard Planting Timeline — St. Clair County, IL

Chard Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 – Mar 12
Transplant Outdoors April 2 Apr 2 – Apr 16
Direct Sow March 19 Mar 19 – Apr 9
Harvest May 28 May 28 – Jul 16
Fall Sowing August 24 Aug 24 – Sep 7

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.8"/week · Only during dry spells

📅 Days to Maturity

50–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

214 days in St. Clair County

Growing Tips for Chard in St. Clair County

Direct sow Chard outdoors after April 02 in St. Clair County when soil has warmed and frost danger has passed.

General growing tips

Direct sow or transplant after last frost. Harvest outer leaves regularly to encourage continuous production. Chard tolerates both heat and light frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Corn
  • Cucumbers

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Chard in St. Clair County, IL?

St. Clair County is in Zone 7a with an average last frost of April 2. Plan your Chard planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Clair County, IL?

St. Clair County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 2 and first fall frost is November 2.

When should I plant Chard in St. Clair County, IL?

In St. Clair County, IL, plant Chard after the last frost (around April 2) and before the first frost (around November 2). Best results when soil holds above 50°F.

What growing zone is St. Clair County, IL for Chard?

St. Clair County sits in USDA Zone 7a. Chard grows reliably in zones 2a through 11b, so it's a good fit here.

Can Chard grow in St. Clair County's climate?

Yes — Chard grows well in St. Clair County's temperate climate. St. Clair County averages a 214-day frost-free season, with last frost around April 2 and first frost around November 2.

🌱

Your St. Clair County Garden Planner — Free

A 22-page printable planner built for St. Clair County (Zone 7a). 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 St. Clair 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.