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When to Plant Microgreens in Greene County, IL

Greene County, Illinois Zone 6a May

Greene County, Illinois gardeners: here's your May plan

Welcome to May in Zone 6a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 13
Avg. first frost October 21
Soil temp (4") 57°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Start microgreens indoors

    You're about 21 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. It's harvest week for microgreens

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

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Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

Greene County, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 21, giving you a growing season of approximately 191 days.

At an elevation of 1,248 feet, Greene County receives approximately 37 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Microgreens during the growing season.

Greene County, IL (Zone 6a) Moderate season
191 days
Last Spring Frost April 13
191 growing days
First Fall Frost October 21
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Greene County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (155 days to spare)
Start indoors: Mar 3 Transplant: Apr 7 🍅 Harvest: Apr 14 – May 12
Recommended (50%) ✓ Fits season (156 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Apr 20 – May 18
Safe Start (90%) ✓ Fits season (155 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: May 2 – May 30

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 Greene County

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

Soil pH

Your soil pH (6.1–6.7) is within Microgreens's preferred range (6.0–7.0).

Soil Texture

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

Drainage

Drainage is adequate for Microgreens.

Organic Matter

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

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

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

Succession Planting Microgreens

37
successive plantings in your 191-day season

Sow every 0.7 weeks. Last sowing by Sep 30 to harvest before frost.

For a dedicated fall crop, sow by Aug 12.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 992 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Microgreens

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

Month Microgreens Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

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

Microgreens 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.

Microgreens needs ~203 GDD — county provides 2,769 GDD Excellent fit

Microgreens Planting Timeline — Greene County, IL

Microgreens Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow March 30 Mar 30 – Apr 20
Harvest April 20 Apr 20 – May 18
Fall Sowing August 12 Aug 12 – Aug 26

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

191 days in Greene County

Growing Tips for Microgreens in Greene County

Direct sow Microgreens outdoors after April 13 in Greene County when soil has warmed and frost danger has passed.

Your generous 191.0-day season in Greene County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Greene County, IL?

Greene County is in Zone 6a with an average last frost of April 13. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Greene County, IL?

Greene County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 21.

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Your Greene County Garden Planner — Free

A 24-page printable planner built for Greene 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 Greene 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.