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When to Plant Epazote in Mercer County, IL

Mercer County, Illinois Zone 5b May

May to-do list for Mercer County, Illinois

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

Avg. last frost April 17
Avg. first frost October 15
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Plant out epazote

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

June will be here before you know it — start on
  • Starting indoors: epazote
  • First harvests: epazote

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Epazote is a pungent Mexican herb traditionally cooked with black beans to reduce their gas-causing properties. It has a strong, unique flavor that is an acquired taste.

Mercer County, Illinois is in USDA Zone 5b. The average last spring frost is April 17 and the first fall frost is October 15, giving you a growing season of approximately 181 days.

At an elevation of 777 feet, Mercer County receives approximately 37.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Epazote to ensure they mature before fall.

Mercer County, IL (Zone 5b) Moderate season
181 days
Last Spring Frost April 17
181 growing days
First Fall Frost October 15
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Mercer County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (62 days to spare)
Start indoors: Feb 22 Transplant: Apr 26 🍅 Harvest: Jun 14 – Aug 9
Recommended (50%) ✓ Fits season (62 days to spare)
Start indoors: Feb 27 Transplant: May 1 🍅 Harvest: Jun 19 – Aug 14
Safe Start (90%) ✓ Fits season (66 days to spare)
Start indoors: Mar 15 Transplant: May 17 🍅 Harvest: Jul 5 – Aug 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 Mercer County

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

Soil pH

Your soil pH (6.3–6.7) is within Epazote's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (4.0%). Annual compost additions will help Epazote.

How to Plant Epazote

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

Succession Planting Epazote

4
successive plantings in your 181-day season

Sow every 5.1 weeks. Last sowing by Aug 16 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Epazote

Epazote needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Epazote Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 2.2" 3.7" 0" ✅ Rainfall sufficient
May 2.2" 4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.6" 0" ✅ Rainfall sufficient
Jul 2.2" 3.7" 0" ✅ Rainfall sufficient
Aug 2.2" 4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.4" 0" ✅ Rainfall sufficient
Oct 2.2" 2.5" 0" ✅ Rainfall sufficient
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

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

Epazote 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.

Epazote needs ~643 GDD — county provides 2,217 GDD Excellent fit

Epazote Planting Timeline — Mercer County, IL

Epazote Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors May 1 May 1 – May 15
Direct Sow April 24 Apr 24 – May 15
Harvest June 19 Jun 19 – Aug 14

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

181 days in Mercer County

Growing Tips for Epazote in Mercer County

Direct sow Epazote outdoors after April 17 in Mercer County when soil has warmed and frost danger has passed.

Your generous 181.0-day season in Mercer County allows multiple plantings of Epazote. Sow every 22.0 days for continuous harvest.

General growing tips

Direct sow after last frost. Epazote grows easily and self-sows aggressively. Use sparingly in cooking as the flavor is very strong. Harvest leaves before flowering for best flavor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Epazote in Mercer County, IL?

Mercer County is in Zone 5b with an average last frost of April 17. Plan your Epazote planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mercer County, IL?

Mercer County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 17 and first fall frost is October 15.

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Your Mercer County Garden Planner — Free

A 24-page printable planner built for Mercer 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 Mercer 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.