When to Plant Mustard Greens in Cook County, MN
What to do in May
A quick May briefing for Cook County, Minnesota gardeners — what's urgent, what's next, and what can wait.
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Harden off and plant mustard greens
Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.
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Outdoor sowing time: mustard greens
Mark the row. Birds and stray feet both have opinions about unmarked beds.
To set up a strong June, finish these tasks
- First harvests: mustard greens
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.
Cook County, Minnesota is in USDA Zone 3b. The average last spring frost is May 20 and the first fall frost is September 29, giving you a growing season of approximately 132 days.
At an elevation of 1,068 feet, Cook County receives approximately 34.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Mustard Greens to ensure they mature before fall.
Cook County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-7.1
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 Cook County
How your county's soil matches Mustard Greens's growing requirements.
Soil pH
Your soil pH (6.1–7.1) overlaps with Mustard Greens's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Cook County is excellent for Mustard Greens — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.4%) — Mustard Greens will thrive.
How to Plant Mustard Greens
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Mustard Greens
Sow every 3.4 weeks. Last sowing by Aug 10 to harvest before frost.
For a dedicated fall crop, sow by Jul 07.
Plant Water Budget
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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | — | 3.5" | 0" | ❄️ Dormant |
| May | 3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 3.9" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 3.2" | 0" | ✅ Rainfall sufficient |
| Oct | — | 2.7" | 0" | ❄️ Dormant |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Cook 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 Planting Timeline — Cook County, MN
Mustard Greens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 8 | Apr 8 – Apr 22 |
| Transplant Outdoors | May 20 | May 20 – Jun 3 |
| Direct Sow | May 13 | May 13 – Jun 3 |
| Harvest | June 24 | Jun 24 – Aug 26 |
| Fall Sowing | July 7 | Jul 7 – Jul 21 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow Harvest |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
30–50 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 3b
📆 Growing Season
132 days in Cook County
Growing Tips for Mustard Greens in Cook County
Direct sow Mustard Greens outdoors after May 20 in Cook County when soil has warmed and frost danger has passed.
Your generous 132.0-day season in Cook 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
Check more plant combinations with our Companion Planting Checker →
Mustard Greens in Other Locations
Frequently Asked Questions
When should I plant Mustard Greens in Cook County, MN?
Cook County is in Zone 3b with an average last frost of May 20. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cook County, MN?
Cook County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 20 and first fall frost is September 29.
Your Cook County Garden Planner — Free
A 24-page printable planner built for Cook 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.