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When to Plant Watercress in Grant County, AR

Grant County, Arkansas Zone 8a April

Top priorities for Grant County, Arkansas gardeners in April

A quick April briefing for Grant County, Arkansas gardeners — what's urgent, what's next, and what can wait.

Avg. last frost March 20
Avg. first frost November 11
Soil temp (4") 57°F
Watering Low
Pest pressure Moderate
Daylight 12.9 hrs
  1. Time to start watercress inside

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

Before May arrives, get these ready
  • 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.

Grant County, Arkansas is in USDA Zone 8a. The average last spring frost is March 20 and the first fall frost is November 11, giving you a growing season of approximately 236 days.

At an elevation of 498 feet, Grant County receives approximately 51.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94°F, providing good warmth for Watercress during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watercress root diseases.

Grant County, AR (Zone 8a) Long season
236 days
Last Spring Frost March 20
236 growing days
First Fall Frost November 11
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Grant County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (157 days to spare)
Start indoors: Feb 6 Transplant: Mar 13 🍅 Harvest: Apr 24 – May 29
Recommended (50%) ✓ Fits season (159 days to spare)
Start indoors: Feb 13 Transplant: Mar 20 🍅 Harvest: May 1 – Jun 5
Safe Start (90%) ✓ Fits season (157 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: May 21 – Jun 25

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 Grant County

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

Soil pH

Your soil pH (5.3–6.6) is more acidic than Watercress prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Grant 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

7
successive plantings in your 236-day season

Sow every 4.6 weeks. Last sowing by Sep 12 to harvest before frost.

For a dedicated fall crop, sow by Sep 02.

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 1,237 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 4.6" 0" ❄️ Dormant
Mar 6.5" 4.4" 2.1" 💧 Light watering
Apr 6.5" 3.8" 2.7" 💧 Light watering
May 6.5" 3.6" 2.9" 💧 Light watering
Jun 6.5" 4.2" 2.3" 💧 Light watering
Jul 6.5" 5" 1.5" 💧 Light watering
Aug 6.5" 5.5" 1" 💧 Light watering
Sep 6.5" 3.6" 2.9" 💧 Light watering
Oct 6.5" 3.7" 2.8" 💧 Light watering
Nov 6.5" 4.4" 2.1" 💧 Light watering
Dec 4.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Grant 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 4,838 GDD Excellent fit

Watercress Planting Timeline — Grant County, AR

Watercress Planting Calendar

Activity When Date Range
Start Indoors February 13 Feb 13 – Feb 27
Transplant Outdoors March 20 Mar 20 – Apr 3
Direct Sow March 6 Mar 6 – Mar 27
Harvest May 1 May 1 – Jun 5
Fall Sowing September 2 Sep 2 – Sep 16

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Transplant Outdoors Direct Sow
April Transplant Outdoors
May Harvest
June Harvest
July
August
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

236 days in Grant County

Growing Tips for Watercress in Grant County

Direct sow Watercress outdoors after March 20 in Grant County when soil has warmed and frost danger has passed.

Your generous 236.0-day season in Grant 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 Grant County, AR?

Grant County is in Zone 8a with an average last frost of March 20. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grant County, AR?

Grant County, Arkansas is in USDA Hardiness Zone 8a. The average last spring frost is March 20 and first fall frost is November 11.

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Your Grant County Garden Planner — Free

A 24-page printable planner built for Grant 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 Grant County, AR. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.