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When to Plant Scarlet Runner Beans in San Juan County, NM

San Juan County, New Mexico Zone 7a May

May to-do list for San Juan County, New Mexico

Your garden in San Juan County, New Mexico is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 12
Avg. first frost October 6
Soil temp (4") 32°F
Watering Critical
Pest pressure Low
Daylight 13.9 hrs
  1. Transplant scarlet runner beans outside

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Direct-sow scarlet runner beans

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

Looking ahead to June
  • Starting indoors: scarlet runner beans

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Scarlet runner beans are ornamental and edible climbing beans with vivid red flowers that attract hummingbirds. Both the young pods and mature beans are edible.

San Juan County, New Mexico is in USDA Zone 7a. The average last spring frost is May 12 and the first fall frost is October 6, giving you a growing season of approximately 147 days.

At an elevation of 8,301 feet, San Juan County receives approximately 14.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 87°F, providing good warmth for Scarlet Runner Beans during the growing season. Sandy soil warms quickly in spring — great for early planting — but Scarlet Runner Beans will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Scarlet Runner Beans successfully. Mulch heavily to conserve soil moisture.

San Juan County, NM (Zone 7a) Short season
147 days
Last Spring Frost May 12
147 growing days
First Fall Frost October 6
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San Juan County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (32 days to spare)
Start indoors: Mar 17 Transplant: May 19 🍅 Harvest: Jul 21 – Aug 25
Recommended (50%) ✓ Fits season (35 days to spare)
Start indoors: Mar 24 Transplant: May 26 🍅 Harvest: Jul 28 – Sep 1
Safe Start (90%) ✓ Fits season (29 days to spare)
Start indoors: Apr 14 Transplant: Jun 16 🍅 Harvest: Aug 18 – Sep 22

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 Scarlet Runner Beans's growing requirements.

Soil pH

Your soil pH (7.3–8.5) is more alkaline than Scarlet Runner Beans prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in San Juan County warms quickly in spring but drains fast. Scarlet Runner Beans will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Scarlet Runner Beans.

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting Scarlet Runner Beans.

How to Plant Scarlet Runner Beans

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

Succession Planting Scarlet Runner Beans

2
successive plantings in your 147-day season

Sow every 6.9 weeks. Last sowing by Jul 18 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,400 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Scarlet Runner Beans

Scarlet Runner 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 Scarlet Runner Beans Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 0.8" 0" ❄️ Dormant
Apr 0.5" 0" ❄️ Dormant
May 4.3" 0.3" 4" 🚿 Regular watering
Jun 4.3" 0.5" 3.8" 🚿 Regular watering
Jul 4.3" 2.5" 1.8" 💧 Light watering
Aug 4.3" 2.6" 1.7" 💧 Light watering
Sep 4.3" 2.2" 2.1" 💧 Light watering
Oct 4.3" 1.3" 3" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in San Juan County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Scarlet Runner 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.

Scarlet Runner Beans needs ~1,068 GDD — county provides 2,241 GDD Excellent fit

Scarlet Runner Beans Planting Timeline — San Juan County, NM

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors March 24 Mar 24 – Apr 7
Transplant Outdoors May 26 May 26 – Jun 9
Direct Sow May 19 May 19 – Jun 9
Harvest July 28 Jul 28 – Sep 1

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

147 days in San Juan County

Growing Tips for Scarlet Runner Beans in San Juan County

Direct sow Scarlet Runner Beans outdoors after May 12 in San Juan County when soil has warmed and frost danger has passed.

Sandy soil in San Juan County dries quickly — mulch Scarlet Runner Beans with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Common pests for Scarlet Runner 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 14" of rain annually. Scarlet Runner Beans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Provide tall trellising for vigorous vines. Direct sow after frost. Harvest pods young for snap beans or let mature for shelling beans. Tubers are perennial in mild climates.

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 Scarlet Runner Beans in San Juan County, NM?

San Juan County is in Zone 7a with an average last frost of May 12. Plan your Scarlet Runner Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Juan County, NM?

San Juan County, New Mexico is in USDA Hardiness Zone 7a. The average last spring frost is May 12 and first fall frost is October 6.

🌱

Your San Juan County Garden Planner — Free

A 24-page printable planner built for San Juan County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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, NM. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.