When to Plant Black Beans in Jefferson County, WA
What to do in May
May is a pivotal month for Jefferson County, Washington gardens. Focus on these tasks first and you'll set up the rest of the season for success.
Black beans are a warm-season legume producing small, dark, protein-rich beans that are a staple in Latin American and Caribbean cuisines.
Jefferson County, Washington is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 29, giving you a growing season of approximately 198 days.
At an elevation of 205 feet, Jefferson County receives approximately 40.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Black Beans during the growing season.
Jefferson County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.8
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 Jefferson County
How your county's soil matches Black Beans's growing requirements.
Soil pH
Your soil pH (5.7–6.8) overlaps with Black Beans's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Jefferson County is excellent for Black Beans — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Black Beans.
Organic Matter
Organic matter is excellent (5.7%) — Black Beans will thrive.
How to Plant Black Beans
Plant Water Budget
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 | — | 6.4" | 0" | ❄️ Dormant |
| Feb | — | 4.7" | 0" | ❄️ Dormant |
| Mar | — | 3.9" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| May | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Jun | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Jul | 4.3" | 0.5" | 3.8" | 🚿 Regular watering |
| Aug | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Sep | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Oct | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Nov | — | 6.3" | 0" | ❄️ Dormant |
| Dec | — | 7.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Jefferson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Black Beans 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.
Black Beans Planting Timeline — Jefferson County, WA
Black Beans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 21 | Apr 21 – May 12 |
| Harvest | July 21 | Jul 21 – Sep 8 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 8b
📆 Growing Season
198 days in Jefferson County
Growing Tips for Black Beans in Jefferson County
Direct sow Black Beans outdoors after April 14 in Jefferson County when soil has warmed and frost danger has passed.
Common pests for Black Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.
General growing tips
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 Jefferson County, WA?
Jefferson County is in Zone 8b with an average last frost of April 14. Plan your Black Beans planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, WA?
Jefferson County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 29.
Your Jefferson County Garden Planner — Free
A 24-page printable planner built for Jefferson County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.