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When to Plant Scarlet Runner Beans in Dona Ana County, NM

Dona Ana County, New Mexico Zone 8b May

May in the garden — Dona Ana County, New Mexico

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

Avg. last frost March 30
Avg. first frost October 30
Soil temp (4") 59°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs
  1. Start scarlet runner beans under lights

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

Coming up in June — start thinking about
  • First harvests: 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.

Dona Ana County, New Mexico is in USDA Zone 8b. The average last spring frost is March 30 and the first fall frost is October 30, giving you a growing season of approximately 214 days.

At an elevation of 4,516 feet, Dona Ana County receives approximately 14.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Scarlet Runner Beans may need afternoon shade and extra watering during peak heat. 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.

Dona Ana County, NM (Zone 8b) Long season
214 days
Last Spring Frost March 30
214 growing days
First Fall Frost October 30

Dona Ana County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (119 days to spare)
Start indoors: Jan 15 Transplant: Mar 19 🍅 Harvest: May 21 – Jun 25
Recommended (50%) ✓ Fits season (102 days to spare)
Start indoors: Feb 9 Transplant: Apr 13 🍅 Harvest: Jun 15 – Jul 20
Safe Start (90%) ✓ Fits season (93 days to spare)
Start indoors: Mar 17 Transplant: May 19 🍅 Harvest: Jul 21 – Aug 25

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 Dona Ana County

How your county's soil matches Scarlet Runner Beans's growing requirements.

Soil pH

Your soil pH (7.3–8.9) 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 Dona Ana 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 (0.8%). 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

4
successive plantings in your 214-day season

Sow every 6.9 weeks. Last sowing by Aug 11 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 2,339 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 0.9" 0" ❄️ Dormant
Mar 4.3" 0.8" 3.5" 🚿 Regular watering
Apr 4.3" 0.4" 3.9" 🚿 Regular watering
May 4.3" 0.3" 4" 🚿 Regular watering
Jun 4.3" 0.6" 3.7" 🚿 Regular watering
Jul 4.3" 2.6" 1.7" 💧 Light watering
Aug 4.3" 2.7" 1.6" 💧 Light watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 4.3" 1.2" 3.1" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Oct in Dona Ana 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 ~1,540 GDD — county provides 4,708 GDD Excellent fit

Scarlet Runner Beans Planting Timeline — Dona Ana County, NM

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors February 9 Feb 9 – Feb 23
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow April 6 Apr 6 – Apr 27
Harvest June 15 Jun 15 – Jul 20

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

Month-by-Month Timeline

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

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 8b

📆 Growing Season

214 days in Dona Ana County

Growing Tips for Scarlet Runner Beans in Dona Ana County

Direct sow Scarlet Runner Beans outdoors after March 30 in Dona Ana County when soil has warmed and frost danger has passed.

Sandy soil in Dona Ana 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.

With summer highs reaching 96°F in Dona Ana County, provide afternoon shade for Scarlet Runner Beans and water deeply in the morning.

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.

Dona Ana 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 Dona Ana County, NM?

Dona Ana County is in Zone 8b with an average last frost of March 30. Plan your Scarlet Runner Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dona Ana County, NM?

Dona Ana County, New Mexico is in USDA Hardiness Zone 8b. The average last spring frost is March 30 and first fall frost is October 30.

🌱

Your Dona Ana County Garden Planner — Free

A 24-page printable planner built for Dona Ana 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.

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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 Dona Ana 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.