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When to Plant Mustard Greens in Douglas County, KS

Douglas County, Kansas Zone 6b May

Your May game plan for Douglas County, Kansas

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

Avg. last frost April 12
Avg. first frost October 25
Soil temp (4") 64°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
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  2. Basket week: mustard greens

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

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  • First harvests: mustard greens

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Mustard greens are fast-growing brassicas with a spicy, peppery kick. They come in green, red, and purple varieties and are excellent cooked or in salads.

Douglas County, Kansas is in USDA Zone 6b. The average last spring frost is April 12 and the first fall frost is October 25, giving you a growing season of approximately 196 days.

At an elevation of 494 feet, Douglas County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Mustard Greens during the growing season.

Douglas County, KS (Zone 6b) Moderate season
196 days
Last Spring Frost April 12
196 growing days
First Fall Frost October 25
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Douglas County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (96 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: May 11 – Jul 13
Recommended (50%) ✓ Fits season (98 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: May 17 – Jul 19
Safe Start (90%) ✓ Fits season (100 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: May 31 – Aug 2

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 Douglas County

How your county's soil matches Mustard Greens's growing requirements.

Soil pH

Your soil pH (6.5–7.6) is more alkaline than Mustard Greens prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Douglas County is excellent for Mustard Greens — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Mustard Greens.

How to Plant Mustard Greens

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 Mustard Greens

7
successive plantings in your 196-day season

Sow every 3.4 weeks. Last sowing by Sep 05 to harvest before frost.

For a dedicated fall crop, sow by Aug 16.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 223 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Mustard Greens

Mustard Greens needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Mustard Greens Needs Rainfall You Supplement Action
Jan 0.7" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 3" 2.7" 0.3" 💧 Light watering
May 3" 4.3" 0" ✅ Rainfall sufficient
Jun 3" 4" 0" ✅ Rainfall sufficient
Jul 3" 3.9" 0" ✅ Rainfall sufficient
Aug 3" 3.6" 0" ✅ Rainfall sufficient
Sep 3" 2.4" 0.6" 💧 Light watering
Oct 3" 1.7" 1.3" 💧 Light watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Douglas County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Mustard Greens 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.

Mustard Greens needs ~700 GDD — county provides 3,430 GDD Excellent fit

Mustard Greens Planting Timeline — Douglas County, KS

Mustard Greens Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 – Mar 22
Transplant Outdoors April 12 Apr 12 – Apr 26
Direct Sow March 29 Mar 29 – Apr 19
Harvest May 17 May 17 – Jul 19
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 Harvest
August Fall Sowing
September
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

196 days in Douglas County

Growing Tips for Mustard Greens in Douglas County

Direct sow Mustard Greens outdoors after April 12 in Douglas County when soil has warmed and frost danger has passed.

Your generous 196.0-day season in Douglas County allows multiple plantings of Mustard Greens. Sow every 15.0 days for continuous harvest.

Common pests for Mustard Greens in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in early spring or fall. Harvest young leaves for milder flavor. Plants bolt quickly in heat so grow as a cool-season crop or provide shade.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mustard Greens in Douglas County, KS?

Douglas County is in Zone 6b with an average last frost of April 12. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Douglas County, KS?

Douglas County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 12 and first fall frost is October 25.

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Your Douglas County Garden Planner — Free

A 24-page printable planner built for Douglas 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 Douglas 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.