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When to Plant Watercress in McPherson County, KS

McPherson County, Kansas Zone 6b May

What to do in May

Your McPherson County, Kansas garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 15
Avg. first frost October 23
Soil temp (4") 64°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
  1. Start watercress under lights

    You're about 24 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Bring in the watercress

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

A few tasks this May that'll pay off in 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.

McPherson County, Kansas is in USDA Zone 6b. The average last spring frost is April 15 and the first fall frost is October 23, giving you a growing season of approximately 191 days.

At an elevation of 850 feet, McPherson County receives approximately 27.1 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Watercress during the growing season.

McPherson County, KS (Zone 6b) Moderate season
191 days
Last Spring Frost April 15
191 growing days
First Fall Frost October 23
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McPherson County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (110 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: May 24 – Jun 28
Recommended (50%) ✓ Fits season (114 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: May 27 – Jul 1
Safe Start (90%) ✓ Fits season (113 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jun 8 – Jul 13

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 McPherson County

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

Soil pH

Your soil pH (6.4–7.6) overlaps with Watercress's range (6.5–7.5), though not a perfect match.

Soil Texture

The loam soil in McPherson 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 (4.3%) — 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 24 to harvest before frost.

For a dedicated fall crop, sow by Aug 14.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.6″/week
Watering frequency 2-3 times/week
Season total 2,762 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 0.6" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 6.5" 2.6" 3.9" 🚿 Regular watering
May 6.5" 4.2" 2.3" 💧 Light watering
Jun 6.5" 4.3" 2.2" 💧 Light watering
Jul 6.5" 3.3" 3.2" 💧 Light watering
Aug 6.5" 3.4" 3.1" 💧 Light watering
Sep 6.5" 2.9" 3.6" 🚿 Regular watering
Oct 6.5" 1.6" 4.9" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in McPherson 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 ~875 GDD — county provides 3,342 GDD Excellent fit

Watercress Planting Timeline — McPherson County, KS

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 15 Apr 15 – Apr 29
Direct Sow April 1 Apr 1 – Apr 22
Harvest May 27 May 27 – Jul 1
Fall Sowing August 14 Aug 14 – Aug 28

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July Harvest
August Fall Sowing
September
October
November
December
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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 6b

📆 Growing Season

191 days in McPherson County

Growing Tips for Watercress in McPherson County

Direct sow Watercress outdoors after April 15 in McPherson County when soil has warmed and frost danger has passed.

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

McPherson County is in Zone 6b with an average last frost of April 15. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is McPherson County, KS?

McPherson County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 15 and first fall frost is October 23.

🌱

Your McPherson County Garden Planner — Free

A 24-page printable planner built for McPherson County (Zone 6b). 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 McPherson 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.