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When to Plant Pole Beans in San Juan County, CO

Pole beans are climbing varieties of green beans that produce over a much longer season than bush types. They require trellising but yield more per square foot.

San Juan County, Colorado is in USDA Zone 4a. The average last spring frost is June 18 and the first fall frost is September 8, giving you a growing season of approximately 82 days.

At an elevation of 7,539 feet, San Juan County receives approximately 20.1 inches of rainfall annually with predominantly loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Pole Beans to ensure they mature before fall.

San Juan County, CO (Zone 4a) Very short season
82 days
Last Spring Frost June 18
82 growing days
First Fall Frost September 8

San Juan County Soil Profile

Soil Type

Loam

Soil pH

6.3-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 5 Transplant: Jun 28 🍅 Harvest: Aug 23 – Oct 18
Recommended (50%) ✗ May not fit
Start indoors: Apr 16 Transplant: Jul 9 🍅 Harvest: Sep 3 – Oct 29
Safe Start (90%) ✗ May not fit
Start indoors: Apr 27 Transplant: Jul 20 🍅 Harvest: Sep 14 – Nov 9

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 San Juan County

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

Soil pH

Your soil pH (6.3โ€“8.0) is more alkaline than Pole Beans prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in San Juan County is excellent for Pole Beans โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Pole Beans.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Pole Beans.

How to Plant Pole Beans

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 237 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Pole Beans

Pole 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 Pole Beans Needs Rainfall You Supplement Action
Jan โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.2" 0" โ„๏ธ Dormant
Mar โ€” 1.6" 0" โ„๏ธ Dormant
Apr โ€” 2" 0" โ„๏ธ Dormant
May โ€” 2.4" 0" โ„๏ธ Dormant
Jun 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Jul 4.3" 2" 2.3" ๐Ÿšฟ Regular watering
Aug 4.3" 2.3" 2" ๐Ÿ’ง Light watering
Sep 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Oct โ€” 1.6" 0" โ„๏ธ Dormant
Nov โ€” 1.3" 0" โ„๏ธ Dormant
Dec โ€” 1.1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Junโ€“Sep in San Juan County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Pole 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.

Pole Beans needs ~719 GDD — county provides 943 GDD Excellent fit

Pole Beans Planting Timeline โ€” San Juan County, CO

Pole Beans Planting Calendar

Activity When Date Range
Start Indoors April 16 Apr 16 โ€“ Apr 30
Transplant Outdoors July 9 Jul 9 โ€“ Jul 23
Direct Sow July 2 Jul 2 โ€“ Jul 23
Harvest September 3 Sep 3 โ€“ Oct 29

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

55โ€“70 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

82 days in San Juan County

Growing Tips for Pole Beans in San Juan County

Direct sow Pole Beans outdoors after June 18 in San Juan County when soil has warmed and frost danger has passed.

Your 82.0-day growing season in San Juan County is tight for Pole Beans (55.0-70.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Pole Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

San Juan County receives only 20" of rain annually. Pole Beans needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

Provide sturdy 6-8 foot poles, tepees, or trellises. Direct sow after last frost. Pick regularly to encourage continued production. Beans fix nitrogen benefiting following crops.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic
  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pole Beans in San Juan County, CO?

San Juan County is in Zone 4a with an average last frost of June 18. Plan your Pole Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is San Juan County, CO?

San Juan County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 18 and first fall frost is September 8.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help San Juan County gardeners in Zone 4a 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 San Juan County, CO. Local conditions may vary. Last updated: April 2026.