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When to Plant Watercress in Henry County, GA

Henry County, Georgia Zone 8a May

May to-do list for Henry County, Georgia

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost March 25
Avg. first frost November 8
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs
  1. Collect watercress at their peak

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

June will be here before you know it — start on
  • First harvests: 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.

Henry County, Georgia is in USDA Zone 8a. The average last spring frost is March 25 and the first fall frost is November 8, giving you a growing season of approximately 228 days.

At an elevation of 379 feet, Henry County receives approximately 52.8 inches of rainfall annually with predominantly clay loam soil. Summer highs average 93°F, providing good warmth for Watercress during the growing season. Clay soil retains moisture well for Watercress, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watercress root diseases.

Henry County, GA (Zone 8a) Long season
228 days
Last Spring Frost March 25
228 growing days
First Fall Frost November 8
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Henry County Soil Profile

Soil Type

Clay Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (154 days to spare)
Start indoors: Feb 8 Transplant: Mar 15 🍅 Harvest: Apr 26 – May 31
Recommended (50%) ✓ Fits season (151 days to spare)
Start indoors: Feb 18 Transplant: Mar 25 🍅 Harvest: May 6 – Jun 10
Safe Start (90%) ✓ Fits season (150 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: May 29 – Jul 3

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 Henry County

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

Soil pH

Your soil pH (5.6–6.7) is more acidic than Watercress prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Watercress.

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

6
successive plantings in your 228-day season

Sow every 4.6 weeks. Last sowing by Sep 09 to harvest before frost.

For a dedicated fall crop, sow by Aug 30.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,284 gal / 100 sq ft
Drought risk

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

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 4.7" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 6.5" 5.4" 1.1" 💧 Light watering
Apr 6.5" 3.9" 2.6" 💧 Light watering
May 6.5" 3.9" 2.6" 💧 Light watering
Jun 6.5" 4.2" 2.3" 💧 Light watering
Jul 6.5" 5.5" 1" 💧 Light watering
Aug 6.5" 5.1" 1.4" 💧 Light watering
Sep 6.5" 4.4" 2.1" 💧 Light watering
Oct 6.5" 3.5" 3" 💧 Light watering
Nov 6.5" 4.2" 2.3" 💧 Light watering
Dec 4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Henry 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 ~988 GDD — county provides 4,503 GDD Excellent fit

Watercress Planting Timeline — Henry County, GA

Watercress Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors March 25 Mar 25 – Apr 8
Direct Sow March 11 Mar 11 – Apr 1
Harvest May 6 May 6 – Jun 10
Fall Sowing August 30 Aug 30 – Sep 13

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 8a

📆 Growing Season

228 days in Henry County

Growing Tips for Watercress in Henry County

Direct sow Watercress outdoors after March 25 in Henry County when soil has warmed and frost danger has passed.

With Henry County's clay soil (30% clay), work in 3-4 inches of compost before planting Watercress. Avoid tilling when soil is wet to prevent compaction.

Your generous 228.0-day season in Henry 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 →

Frequently Asked Questions

When should I plant Watercress in Henry County, GA?

Henry County is in Zone 8a with an average last frost of March 25. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Henry County, GA?

Henry County, Georgia is in USDA Hardiness Zone 8a. The average last spring frost is March 25 and first fall frost is November 8.

🌱

Your Henry County Garden Planner — Free

A 24-page printable planner built for Henry County (Zone 8a). 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 Henry County, GA. 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.