Blog

When to Plant Collard Greens in Thomas County, KS

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.

Thomas County, Kansas is in USDA Zone 5b. The average last spring frost is April 30 and the first fall frost is October 12, giving you a growing season of approximately 165 days.

At an elevation of 810 feet, Thomas County receives approximately 26.4 inches of rainfall annually with predominantly loam soil. Summer highs average 88ยฐF, providing good warmth for Collard Greens during the growing season.

Thomas County, KS (Zone 5b) Moderate season
165 days
Last Spring Frost April 30
165 growing days
First Fall Frost October 12

Thomas County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (45 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: Jun 20 – Aug 22
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jun 25 – Aug 27
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Jul 9 – Sep 10

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 Thomas County

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

Soil pH

Your soil pH (6.8โ€“7.5) is more alkaline than Collard Greens prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Thomas County is excellent for Collard Greens โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.1%) โ€” Collard Greens will thrive.

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

3
successive plantings in your 165-day season

Sow every 6.3 weeks. Last sowing by Jul 29 to harvest before frost.

For a dedicated fall crop, sow by Aug 03.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.7″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 226 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

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 โ€” 2.1" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 2.2" 0" โ„๏ธ Dormant
Apr 3.5" 3.1" 0.4" ๐Ÿ’ง Light watering
May 3.5" 3.2" 0.3" ๐Ÿ’ง Light watering
Jun 3.5" 2" 1.5" ๐Ÿ’ง Light watering
Jul 3.5" 2.3" 1.2" ๐Ÿ’ง Light watering
Aug 3.5" 2.6" 0.9" ๐Ÿ’ง Light watering
Sep 3.5" 2.1" 1.4" ๐Ÿ’ง Light watering
Oct 3.5" 2.3" 1.2" ๐Ÿ’ง Light watering
Nov โ€” 1.7" 0" โ„๏ธ Dormant
Dec โ€” 1.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Thomas County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,040 GDD — county provides 2,640 GDD Excellent fit

Collard Greens Planting Timeline โ€” Thomas County, KS

Collard Greens Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 โ€“ Apr 9
Transplant Outdoors April 30 Apr 30 โ€“ May 14
Direct Sow April 16 Apr 16 โ€“ May 7
Harvest June 25 Jun 25 โ€“ Aug 27
Fall Sowing August 3 Aug 3 โ€“ Aug 17

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.8"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

55โ€“75 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

165 days in Thomas County

Growing Tips for Collard Greens in Thomas County

Direct sow Collard Greens outdoors after April 30 in Thomas 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 Thomas County, KS?

Thomas County is in Zone 5b with an average last frost of April 30. Plan your Collard Greens planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Thomas County, KS?

Thomas County, Kansas is in USDA Hardiness Zone 5b. The average last spring frost is April 30 and first fall frost is October 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Thomas County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Thomas County, KS. Local conditions may vary. Last updated: April 2026.