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When to Plant Watercress in Caswell County, NC

Caswell County, North Carolina Zone 7b May

Top priorities for Caswell County, North Carolina gardeners in May

A quick May briefing for Caswell County, North Carolina gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 6
Avg. first frost October 31
Soil temp (4") 66°F
Watering Moderate
Pest pressure Moderate
Daylight 13.9 hrs
  1. Start watercress indoors

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Start harvesting watercress

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

Looking ahead to June
  • 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.

Caswell County, North Carolina is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is October 31, giving you a growing season of approximately 208 days.

At an elevation of 608 feet, Caswell County receives approximately 42.7 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.

Caswell County, NC (Zone 7b) Long season
208 days
Last Spring Frost April 6
208 growing days
First Fall Frost October 31
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Caswell County Soil Profile

Soil Type

Clay Loam

Soil pH

5.7-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (134 days to spare)
Start indoors: Feb 21 Transplant: Mar 28 🍅 Harvest: May 9 – Jun 13
Recommended (50%) ✓ Fits season (131 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: May 18 – Jun 22
Safe Start (90%) ✓ Fits season (127 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jun 4 – Jul 9

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 Caswell County

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

Soil pH

Your soil pH (5.7–6.2) is more acidic than Watercress prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). 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 208-day season

Sow every 4.6 weeks. Last sowing by Sep 01 to harvest before frost.

For a dedicated fall crop, sow by Aug 22.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,181 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 3.9" 0" ❄️ Dormant
Feb 3.8" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 6.5" 3.2" 3.3" 🚿 Regular watering
May 6.5" 3" 3.5" 🚿 Regular watering
Jun 6.5" 4" 2.5" 💧 Light watering
Jul 6.5" 4.8" 1.7" 💧 Light watering
Aug 6.5" 3.7" 2.8" 💧 Light watering
Sep 6.5" 2.9" 3.6" 🚿 Regular watering
Oct 6.5" 2.5" 4" 🚿 Regular watering
Nov 3.3" 0" ❄️ Dormant
Dec 3.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Caswell 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 4,264 GDD Excellent fit

Watercress Planting Timeline — Caswell County, NC

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow March 23 Mar 23 – Apr 13
Harvest May 18 May 18 – Jun 22
Fall Sowing August 22 Aug 22 – Sep 5

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors 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 7b

📆 Growing Season

208 days in Caswell County

Growing Tips for Watercress in Caswell County

Direct sow Watercress outdoors after April 06 in Caswell County when soil has warmed and frost danger has passed.

With Caswell County's clay soil (34% clay), work in 3-4 inches of compost before planting Watercress. Avoid tilling when soil is wet to prevent compaction.

Your generous 208.0-day season in Caswell 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 Caswell County, NC?

Caswell County is in Zone 7b with an average last frost of April 6. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Caswell County, NC?

Caswell County, North Carolina is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is October 31.

🌱

Your Caswell County Garden Planner — Free

A 24-page printable planner built for Caswell County (Zone 7b). 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 Caswell County, NC. 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.