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When to Plant Collard Greens in Montgomery County, MD

Montgomery County, Maryland Zone 7b May

What to do in May

We've pulled the most time-sensitive tasks for Montgomery County, Maryland this May and put them front and centre. Tackle them in order.

Avg. last frost April 16
Avg. first frost October 20
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 14.1 hrs
  1. Start collard greens under lights

    These need a head start before your last frost (April 16). Sow into cells now so you're ready to transplant in a few weeks.

To set up a strong June, finish these tasks
  • First harvests: collard greens

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Collard greens are a heat-tolerant member of the cabbage family with large, sturdy leaves. They are a Southern staple and one of the most nutritious leafy greens.

Montgomery County, Maryland is in USDA Zone 7b. The average last spring frost is April 16 and the first fall frost is October 20, giving you a growing season of approximately 187 days.

At an elevation of 661 feet, Montgomery County receives approximately 41.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Collard Greens during the growing season.

Montgomery County, MD (Zone 7b) Moderate season
187 days
Last Spring Frost April 16
187 growing days
First Fall Frost October 20

Montgomery County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: Jun 7 – Aug 9
Recommended (50%) ✓ Fits season (68 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Jun 11 – Aug 13
Safe Start (90%) ✓ Fits season (57 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Jul 5 – Sep 6

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 Montgomery County

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

Soil pH

Your soil pH (5.4–6.7) overlaps with Collard Greens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Collard Greens.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Collard Greens.

How to Plant Collard Greens

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Collard Greens

4
successive plantings in your 187-day season

Sow every 6.3 weeks. Last sowing by Aug 06 to harvest before frost.

For a dedicated fall crop, sow by Aug 11.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Collard Greens

Collard Greens needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Collard Greens Needs Rainfall You Supplement Action
Jan 2.7" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 3.4" 0" ❄️ Dormant
Apr 3.5" 3.9" 0" ✅ Rainfall sufficient
May 3.5" 3.9" 0" ✅ Rainfall sufficient
Jun 3.5" 3.7" 0" ✅ Rainfall sufficient
Jul 3.5" 3.9" 0" ✅ Rainfall sufficient
Aug 3.5" 3.7" 0" ✅ Rainfall sufficient
Sep 3.5" 3.9" 0" ✅ Rainfall sufficient
Oct 3.5" 3.2" 0.3" 💧 Light watering
Nov 3.6" 0" ❄️ Dormant
Dec 2.9" 0" ❄️ Dormant

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

Collard 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.

Collard Greens needs ~1,284 GDD — county provides 3,693 GDD Excellent fit

Collard Greens Planting Timeline — Montgomery County, MD

Collard Greens Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 2 Apr 2 – Apr 23
Harvest June 11 Jun 11 – Aug 13
Fall Sowing August 11 Aug 11 – Aug 25

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

187 days in Montgomery County

Growing Tips for Collard Greens in Montgomery County

Direct sow Collard Greens outdoors after April 16 in Montgomery County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors or direct sow 4-6 weeks before last frost. Harvest lower leaves first, leaving the growing tip intact. Flavor improves after exposure to frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Collard Greens in Montgomery County, MD?

Montgomery County is in Zone 7b with an average last frost of April 16. Plan your Collard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Montgomery County, MD?

Montgomery County, Maryland is in USDA Hardiness Zone 7b. The average last spring frost is April 16 and first fall frost is October 20.

🌱

Your Montgomery County Garden Planner — Free

A 24-page printable planner built for Montgomery County (Zone 7b). 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 Montgomery County, MD. 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.