Blog

When to Plant Watercress in Jackson County, KS

Jackson County, Kansas Zone 6a May

Jackson County, Kansas gardeners: here's your May plan

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

Avg. last frost April 14
Avg. first frost October 22
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Time to start watercress inside

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

  2. Bring in the watercress

    If you can't use it all right away, check the food-preservation section of your planner.

Coming up in June — start thinking about
  • 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.

Jackson County, Kansas is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 22, giving you a growing season of approximately 191 days.

At an elevation of 909 feet, Jackson County receives approximately 25.8 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Watercress during the growing season.

Jackson County, KS (Zone 6a) Moderate season
191 days
Last Spring Frost April 14
191 growing days
First Fall Frost October 22

Jackson County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (111 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: May 21 – Jun 25
Recommended (50%) ✓ Fits season (114 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: May 26 – Jun 30
Safe Start (90%) ✓ Fits season (116 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jun 11 – Jul 16

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 Jackson County

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

Soil pH

Your soil pH (6.8–7.8) overlaps with Watercress's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Drainage

Watercress is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is excellent (4.1%) — Watercress will thrive.

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 191-day season

Sow every 4.6 weeks. Last sowing by Aug 23 to harvest before frost.

For a dedicated fall crop, sow by Aug 13.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.7″/week
Watering frequency 2-3 times/week
Season total 2,820 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 0.7" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 6.5" 2.4" 4.1" 🚿 Regular watering
May 6.5" 3.8" 2.7" 💧 Light watering
Jun 6.5" 4.3" 2.2" 💧 Light watering
Jul 6.5" 3.7" 2.8" 💧 Light watering
Aug 6.5" 3.4" 3.1" 💧 Light watering
Sep 6.5" 2.1" 4.4" 🚿 Regular watering
Oct 6.5" 1.6" 4.9" 🚿 Regular watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jackson 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 ~688 GDD — county provides 2,626 GDD Excellent fit

Watercress Planting Timeline — Jackson County, KS

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 31 Mar 31 – Apr 21
Harvest May 26 May 26 – Jun 30
Fall Sowing August 13 Aug 13 – Aug 27

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

191 days in Jackson County

Growing Tips for Watercress in Jackson County

Direct sow Watercress outdoors after April 14 in Jackson County when soil has warmed and frost danger has passed.

Your generous 191.0-day season in Jackson 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 Jackson County, KS?

Jackson County is in Zone 6a with an average last frost of April 14. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jackson County, KS?

Jackson County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 22.

🌱

Your Jackson County Garden Planner — Free

A 24-page printable planner built for Jackson County (Zone 6a). 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 Jackson County, KS. 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.