When to Plant Collard Greens in St. Louis County, MN
Top priorities for St. Louis County, Minnesota gardeners in May
Your garden in St. Louis County, Minnesota is working on a schedule, even when you're not. Here's where you should be this May.
-
Direct-sow collard greens
Your soil is 49°F — warm enough for these to germinate without babying.
June prep starts now
- Transplants going out: collard greens
- Fall sowing: collard greens
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.
St. Louis County, Minnesota is in USDA Zone 3b. The average last spring frost is June 2 and the first fall frost is September 10, giving you a growing season of approximately 100 days.
At an elevation of 531 feet, St. Louis County receives approximately 36.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Collard Greens to ensure they mature before fall.
St. Louis County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7
Drainage
Well Drained
Plant Planting Risk Windows
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 St. Louis County
How your county's soil matches Collard Greens's growing requirements.
Soil pH
Your soil pH (6.0–7.0) is within Collard Greens's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in St. Louis 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 excellent (4.0%) — Collard Greens will thrive.
How to Plant Collard Greens
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Collard Greens
Sow every 6.3 weeks. Last sowing by Jun 27 to harvest before frost.
For a dedicated fall crop, sow by Jun 18.
Plant Water Budget
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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | — | 3.2" | 0" | ❄️ Dormant |
| May | — | 3.9" | 0" | ❄️ Dormant |
| Jun | 3.5" | 5.1" | 0" | ✅ Rainfall sufficient |
| Jul | 3.5" | 4.4" | 0" | ✅ Rainfall sufficient |
| Aug | 3.5" | 3.7" | 0" | ✅ Rainfall sufficient |
| Sep | 3.5" | 3.1" | 0.4" | 💧 Light watering |
| Oct | — | 2.8" | 0" | ❄️ Dormant |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in St. Louis 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 Planting Timeline — St. Louis County, MN
Collard Greens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 21 | Apr 21 – May 5 |
| Transplant Outdoors | June 2 | Jun 2 – Jun 16 |
| Direct Sow | May 26 | May 26 – Jun 16 |
| Harvest | July 28 | Jul 28 – Sep 29 |
| Fall Sowing | June 18 | Jun 18 – Jul 2 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors Direct Sow |
| June | Transplant Outdoors Direct Sow Fall Sowing |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | Harvest |
| 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: ideal
🗺️ USDA Zone
Zone 3b
📆 Growing Season
100 days in St. Louis County
Growing Tips for Collard Greens in St. Louis County
Direct sow Collard Greens outdoors after June 02 in St. Louis 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
Check more plant combinations with our Companion Planting Checker →
Collard Greens in Other Locations
Frequently Asked Questions
When should I plant Collard Greens in St. Louis County, MN?
St. Louis County is in Zone 3b with an average last frost of June 2. Plan your Collard Greens planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Louis County, MN?
St. Louis County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is June 2 and first fall frost is September 10.
Your St. Louis County Garden Planner — Free
A 24-page printable planner built for St. Louis County (Zone 3b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.