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When to Plant Watercress in Jefferson County, MS

Jefferson County, Mississippi Zone 8b May

Top priorities for Jefferson County, Mississippi gardeners in May

A quick May briefing for Jefferson County, Mississippi gardeners — what's urgent, what's next, and what can wait.

Avg. last frost March 12
Avg. first frost November 13
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Basket week: watercress

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

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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.

Jefferson County, Mississippi is in USDA Zone 8b. The average last spring frost is March 12 and the first fall frost is November 13, giving you a growing season of approximately 246 days.

At an elevation of 82 feet, Jefferson County receives approximately 55.9 inches of rainfall annually with predominantly clay loam soil. Summer highs average 94°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.

Jefferson County, MS (Zone 8b) Long season
246 days
Last Spring Frost March 12
246 growing days
First Fall Frost November 13

Jefferson County Soil Profile

Soil Type

Clay Loam

Soil pH

5.8-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (165 days to spare)
Start indoors: Jan 30 Transplant: Mar 6 🍅 Harvest: Apr 17 – May 22
Recommended (50%) ✓ Fits season (169 days to spare)
Start indoors: Feb 5 Transplant: Mar 12 🍅 Harvest: Apr 23 – May 28
Safe Start (90%) ✓ Fits season (159 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🍅 Harvest: May 20 – Jun 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 Jefferson County

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

Soil pH

Your soil pH (5.8–6.5) is more acidic than Watercress prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Watercress.

Organic Matter

Organic matter is moderate (2.8%). 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

7
successive plantings in your 246-day season

Sow every 4.6 weeks. Last sowing by Sep 14 to harvest before frost.

For a dedicated fall crop, sow by Sep 04.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 209 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 5.1" 0" ❄️ Dormant
Feb 4.4" 0" ❄️ Dormant
Mar 6.5" 5.9" 0.6" 💧 Light watering
Apr 6.5" 4.6" 1.9" 💧 Light watering
May 6.5" 4.3" 2.2" 💧 Light watering
Jun 6.5" 5.2" 1.3" 💧 Light watering
Jul 6.5" 6.1" 0.4" 💧 Light watering
Aug 6.5" 4.8" 1.7" 💧 Light watering
Sep 6.5" 3.7" 2.8" 💧 Light watering
Oct 6.5" 3.1" 3.4" 🚿 Regular watering
Nov 6.5" 4.5" 2" 💧 Light watering
Dec 4.1" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Jefferson 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 ~1,025 GDD — county provides 5,043 GDD Excellent fit

Watercress Planting Timeline — Jefferson County, MS

Watercress Planting Calendar

Activity When Date Range
Start Indoors February 5 Feb 5 – Feb 19
Transplant Outdoors March 12 Mar 12 – Mar 26
Direct Sow February 26 Feb 26 – Mar 19
Harvest April 23 Apr 23 – May 28
Fall Sowing September 4 Sep 4 – Sep 18

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

246 days in Jefferson County

Growing Tips for Watercress in Jefferson County

Direct sow Watercress outdoors after March 12 in Jefferson County when soil has warmed and frost danger has passed.

With Jefferson 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 246.0-day season in Jefferson 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 Jefferson County, MS?

Jefferson County is in Zone 8b with an average last frost of March 12. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, MS?

Jefferson County, Mississippi is in USDA Hardiness Zone 8b. The average last spring frost is March 12 and first fall frost is November 13.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 8b). 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 Jefferson County, MS. 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.