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When to plant Watercress in Mapleton, IL

For Watercress in Mapleton, the safe spring window opens around April 9 and closes around April 30. Last expected frost is April 23, first fall frost October 12, giving a 172-day growing season. A second sowing from August 3 to August 17 extends the harvest into fall.

When to Plant Watercress in Mapleton, IL

Peoria County, Illinois Zone 6a July

July to-do list for Peoria County, Illinois

A quick July briefing for Peoria County, Illinois gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 23
Avg. first frost October 12
Soil temp (4") 76°F
Watering Moderate
Pest pressure High
Daylight 14.7 hrs
  1. Harvest watercress as they ripen

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

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

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Watercress is a semi-aquatic plant with a peppery, tangy flavor rich in vitamins and minerals. It grows naturally along streams and can be cultivated in containers with standing water.

Mapleton, Illinois is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 12, giving you a growing season of approximately 172 days.

At an elevation of 884 feet, Peoria County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Watercress during the growing season.

Mapleton, IL (Zone 6a) Moderate season
172 days
Last Spring Frost April 23
172 growing days
First Fall Frost October 12

Mapleton Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

Drainage

Well Drained

Watercress Planting Risk Windows

Early Start (70% safe) ✓ Fits season (97 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: May 29 – Jul 3
Recommended (50%) ✓ Fits season (95 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jun 4 – Jul 9
Safe Start (90%) ✓ Fits season (96 days to spare)
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Jun 19 – Jul 24

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 Mapleton

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

Soil pH

Your soil pH (6.1–7.0) overlaps with Watercress's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Watercress will thrive.

How to Plant Watercress

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Succession Planting Watercress

5
successive plantings in your 172-day season

Sow every 4.6 weeks. Last sowing by Aug 13 to harvest before frost.

For a dedicated fall crop, sow by Aug 03.

Watercress Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,063 gal / 100 sq ft

Monthly Watering Guide for Watercress

Watercress needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Watercress Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 6.5" 3.5" 3" 💧 Light watering
May 6.5" 4.2" 2.3" 💧 Light watering
Jun 6.5" 3.9" 2.6" 💧 Light watering
Jul 6.5" 3.2" 3.3" 🚿 Regular watering
Aug 6.5" 3.4" 3.1" 💧 Light watering
Sep 6.5" 3.2" 3.3" 🚿 Regular watering
Oct 6.5" 2.8" 3.7" 🚿 Regular watering
Nov 1.9" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

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

Watercress 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.

Watercress needs ~725 GDD — county provides 2,494 GDD Excellent fit

Watercress Planting Timeline — Mapleton, IL

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 23 Apr 23 – May 7
Direct Sow April 9 Apr 9 – Apr 30
Harvest June 4 Jun 4 – Jul 9
Fall Sowing August 3 Aug 3 – Aug 17

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

172 days in Peoria County

Growing Tips for Watercress in Mapleton

Direct sow Watercress outdoors after April 23 in Peoria County when soil has warmed and frost danger has passed.

Your generous 172.0-day season in Peoria County allows multiple plantings of Watercress. Sow every 20.0 days for continuous harvest.

Common pests for Watercress in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Grow in containers with trays of water kept fresh. Provide partial shade and cool conditions. Harvest stems by cutting above water level. Replace water frequently to prevent stagnation.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

When should I plant Watercress in Mapleton, IL?

In Mapleton, IL, plant Watercress after the last frost (around April 23) and before the first frost (around October 12). Best results when soil holds above 50°F.

What growing zone is Mapleton, IL for Watercress?

Mapleton sits in USDA Zone 6a. Watercress grows reliably in zones 3a through 11b, so it's a good fit here.

Can Watercress grow in Mapleton's climate?

Yes — Watercress grows well in Mapleton's temperate climate. Mapleton averages a 172-day frost-free season, with last frost around April 23 and first frost around October 12.

🌱

Your Peoria County Garden Planner — Free

A 22-page printable planner built for Peoria 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 Peoria County, IL. Local conditions may vary. Last updated: July 2026.