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When to Plant Mustard Greens in Delaware County, OK

Delaware County, Oklahoma Zone 7a May

May in the garden — Delaware County, Oklahoma

Here's what deserves your attention in Delaware County, Oklahoma this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost April 9
Avg. first frost October 25
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Begin indoor sowing: mustard greens

    You're about 25 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Basket week: mustard greens

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Get ahead of June
  • 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.

Delaware County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 9 and the first fall frost is October 25, giving you a growing season of approximately 199 days.

At an elevation of 440 feet, Delaware County receives approximately 30.3 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Mustard Greens during the growing season.

Delaware County, OK (Zone 7a) Moderate season
199 days
Last Spring Frost April 9
199 growing days
First Fall Frost October 25

Delaware County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (100 days to spare)
Start indoors: Feb 27 Transplant: Apr 3 🍅 Harvest: May 8 – Jul 10
Recommended (50%) ✓ Fits season (101 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: May 14 – Jul 16
Safe Start (90%) ✓ Fits season (103 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: May 28 – Jul 30

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 Delaware County

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

Soil pH

Your soil pH (6.3–7.6) overlaps with Mustard Greens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.6%). 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

8
successive plantings in your 199-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 129 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 0.9" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 3" 3.2" 0" ✅ Rainfall sufficient
May 3" 4.8" 0" ✅ Rainfall sufficient
Jun 3" 4.3" 0" ✅ Rainfall sufficient
Jul 3" 4" 0" ✅ Rainfall sufficient
Aug 3" 3.7" 0" ✅ Rainfall sufficient
Sep 3" 3.1" 0" ✅ Rainfall sufficient
Oct 3" 1.9" 1.1" 💧 Light watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Delaware 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 ~820 GDD — county provides 4,079 GDD Excellent fit

Mustard Greens Planting Timeline — Delaware County, OK

Mustard Greens Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 – Mar 19
Transplant Outdoors April 9 Apr 9 – Apr 23
Direct Sow March 26 Mar 26 – Apr 16
Harvest May 14 May 14 – Jul 16
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

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: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

199 days in Delaware County

Growing Tips for Mustard Greens in Delaware County

Direct sow Mustard Greens outdoors after April 09 in Delaware County when soil has warmed and frost danger has passed.

Your generous 199.0-day season in Delaware 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 Delaware County, OK?

Delaware County is in Zone 7a with an average last frost of April 9. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Delaware County, OK?

Delaware County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 9 and first fall frost is October 25.

🌱

Your Delaware County Garden Planner — Free

A 24-page printable planner built for Delaware 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 Delaware County, OK. 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.