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When to Plant Black Beans in Aroostook County, ME

Black beans are a warm-season legume producing small, dark, protein-rich beans that are a staple in Latin American and Caribbean cuisines.

Aroostook County, Maine is in USDA Zone 3b. The average last spring frost is May 18 and the first fall frost is September 24, giving you a growing season of approximately 129 days.

At an elevation of 314 feet, Aroostook County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78ยฐF, so choose short-season varieties of Black Beans to ensure they mature before fall.

Aroostook County, ME (Zone 3b) Short season
129 days
Last Spring Frost May 18
129 growing days
First Fall Frost September 24

Aroostook County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Transplant: May 12 🍅 Harvest: Aug 11 – Sep 15
Recommended (50%) ✓ Fits season (3 days to spare)
Transplant: May 18 🍅 Harvest: Aug 17 – Sep 21
Safe Start (90%) ✓ Fits season (0 days to spare)
Transplant: Jun 1 🍅 Harvest: Aug 31 – Oct 5

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 Aroostook County

How your county's soil matches Black Beans's growing requirements.

Soil pH

Your soil pH (4.9โ€“6.3) is more acidic than Black Beans prefers (6.0โ€“7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Aroostook County is excellent for Black Beans โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Black Beans.

How to Plant Black Beans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 โ€” 2.8" 0" โ„๏ธ Dormant
Feb โ€” 2.7" 0" โ„๏ธ Dormant
Mar โ€” 3.3" 0" โ„๏ธ Dormant
Apr โ€” 3.5" 0" โ„๏ธ Dormant
May 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Jun 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Jul 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
Aug 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
Sep 4.3" 3.9" 0.4" ๐Ÿ’ง Light watering
Oct โ€” 3.2" 0" โ„๏ธ Dormant
Nov โ€” 2.9" 0" โ„๏ธ Dormant
Dec โ€” 3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Aroostook County). Supplement amounts are based on average rainfall โ€” 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" 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.

Black Beans needs ~892 GDD — county provides 1,096 GDD Good fit

Black Beans Planting Timeline โ€” Aroostook County, ME

Black Beans Planting Calendar

Activity When Date Range
Direct Sow June 1 Jun 1 โ€“ Jun 22
Harvest August 31 Aug 31 โ€“ Oct 5

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June Direct Sow
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 3b

๐Ÿ“† Growing Season

129 days in Aroostook County

Growing Tips for Black Beans in Aroostook County

Direct sow Black Beans outdoors after May 18 in Aroostook County when soil has warmed and frost danger has passed.

Your 129.0-day growing season in Aroostook County is tight for Black Beans (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Black Beans in Aroostook County, ME?

Aroostook County is in Zone 3b with an average last frost of May 18. Plan your Black Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Aroostook County, ME?

Aroostook County, Maine is in USDA Hardiness Zone 3b. The average last spring frost is May 18 and first fall frost is September 24.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Aroostook County gardeners in Zone 3b 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 Aroostook County, ME. Local conditions may vary. Last updated: April 2026.