When to Plant Black Beans in Rock County, MN
Black beans are a warm-season legume producing small, dark, protein-rich beans that are a staple in Latin American and Caribbean cuisines.
Rock County, Minnesota is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 2, giving you a growing season of approximately 153 days.
At an elevation of 916 feet, Rock County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Black Beans to ensure they mature before fall.
Rock County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.9
Drainage
Well Drained
Monthly Watering Guide for Black Beans
Black Beans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Black Beans Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.4" | 0" | ❄️ Dormant |
| Apr | — | 2.9" | 0" | ❄️ Dormant |
| May | 4.3" | 3.3" | 1" | 💧 Light watering |
| Jun | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jul | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Aug | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Sep | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Oct | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Rock County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Black Beans Planting Timeline — Rock County, MN
Black Beans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 16 | May 16 – Jun 6 |
| Harvest | August 15 | Aug 15 – Oct 3 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Direct Sow |
| June | Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 4b
📆 Growing Season
153 days in Rock County
Growing Tips for Rock County
Direct sow after last frost. Provide support for climbing varieties. Allow pods to dry fully on the vine before harvesting. Thresh dried pods by hand or in a pillowcase.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Black Beans in Other Locations
Frequently Asked Questions
When should I plant Black Beans in Rock County, MN?
Rock County is in Zone 4b with an average last frost of May 2. Plan your Black Beans planting based on this frost date — see the calendar above for exact timing.
What planting zone is Rock County, MN?
Rock County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 2.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Rock County gardeners in Zone 4b 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.