Blog

When to Plant Watercress in Campbell County, TN

Campbell County, Tennessee Zone 7a May

May in Campbell County, Tennessee — your action list

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Campbell County, Tennessee.

Avg. last frost April 11
Avg. first frost October 25
Soil temp (4") 56°F
Watering Moderate
Pest pressure Low
Daylight 13.9 hrs
  1. Sow watercress in trays indoors

    Label every cell. You will absolutely forget which is which otherwise.

  2. Basket week: watercress

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

Before June arrives, get these ready
  • First harvests: watercress

Instant PDF download. No spam, unsubscribe any time.

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.

Campbell County, Tennessee is in USDA Zone 7a. The average last spring frost is April 11 and the first fall frost is October 25, giving you a growing season of approximately 197 days.

At an elevation of 2,606 feet, Campbell County receives approximately 43.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Watercress during the growing season.

Campbell County, TN (Zone 7a) Moderate season
197 days
Last Spring Frost April 11
197 growing days
First Fall Frost October 25
Share this guide:

Campbell County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (120 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: May 17 – Jun 21
Recommended (50%) ✓ Fits season (120 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: May 23 – Jun 27
Safe Start (90%) ✓ Fits season (109 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Jun 15 – Jul 20

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 Campbell County

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

Soil pH

Your soil pH (5.7–7.1) is more acidic than Watercress prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.1%). 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

5
successive plantings in your 197-day season

Sow every 4.6 weeks. Last sowing by Aug 26 to harvest before frost.

For a dedicated fall crop, sow by Aug 16.

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 993 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 4" 0" ❄️ Dormant
Feb 3.6" 0" ❄️ Dormant
Mar 4.1" 0" ❄️ Dormant
Apr 6.5" 2.9" 3.6" 🚿 Regular watering
May 6.5" 3" 3.5" 🚿 Regular watering
Jun 6.5" 4.4" 2.1" 💧 Light watering
Jul 6.5" 3.9" 2.6" 💧 Light watering
Aug 6.5" 4.5" 2" 💧 Light watering
Sep 6.5" 3.6" 2.9" 💧 Light watering
Oct 6.5" 2.9" 3.6" 🚿 Regular watering
Nov 3.2" 0" ❄️ Dormant
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Campbell 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 2,856 GDD Excellent fit

Watercress Planting Timeline — Campbell County, TN

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow March 28 Mar 28 – Apr 18
Harvest May 23 May 23 – Jun 27
Fall Sowing August 16 Aug 16 – Aug 30

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
October
November
December
Share this guide:

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 7a

📆 Growing Season

197 days in Campbell County

Growing Tips for Watercress in Campbell County

Direct sow Watercress outdoors after April 11 in Campbell County when soil has warmed and frost danger has passed.

Your generous 197.0-day season in Campbell 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 Campbell County, TN?

Campbell County is in Zone 7a with an average last frost of April 11. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Campbell County, TN?

Campbell County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 11 and first fall frost is October 25.

🌱

Your Campbell County Garden Planner — Free

A 24-page printable planner built for Campbell County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Campbell County, TN. 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.