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When to Plant Scarlet Runner Beans in Siskiyou County, CA

Siskiyou County, California Zone 8a May

Top priorities for Siskiyou County, California gardeners in May

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 15
Avg. first frost October 1
Soil temp (4") 67°F
Watering Critical
Pest pressure Moderate
Daylight 14.3 hrs
  1. Get scarlet runner beans in the ground

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Sow scarlet runner beans where they'll grow

    These tolerate cool soil, so you're not gambling by sowing now.

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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.

Siskiyou County, California is in USDA Zone 8a. The average last spring frost is May 15 and the first fall frost is October 1, giving you a growing season of approximately 139 days.

At an elevation of 251 feet, Siskiyou County receives approximately 36 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 84°F, so choose short-season varieties of Scarlet Runner Beans to ensure they mature before fall. 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.

Siskiyou County, CA (Zone 8a) Short season
139 days
Last Spring Frost May 15
139 growing days
First Fall Frost October 1
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Siskiyou County Soil Profile

Soil Type

Sandy Loam

Soil pH

6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Mar 18 Transplant: May 20 🍅 Harvest: Jul 22 – Aug 26
Recommended (50%) ✓ Fits season (27 days to spare)
Start indoors: Mar 27 Transplant: May 29 🍅 Harvest: Jul 31 – Sep 4
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Apr 30 Transplant: Jul 2 🍅 Harvest: Sep 3 – Oct 8

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 Siskiyou County

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

Soil pH

Your soil pH (6.0–6.9) is within Scarlet Runner Beans's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help 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 139-day season

Sow every 6.9 weeks. Last sowing by Jul 13 to harvest before frost.

Plant Water Budget

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

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 7.3" 0" ❄️ Dormant
Feb 7.1" 0" ❄️ Dormant
Mar 5.3" 0" ❄️ Dormant
Apr 3.3" 0" ❄️ Dormant
May 4.3" 1" 3.3" 🚿 Regular watering
Jun 4.3" 0.2" 4.1" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.4" 3.9" 🚿 Regular watering
Oct 4.3" 1.6" 2.7" 🚿 Regular watering
Nov 3.1" 0" ❄️ Dormant
Dec 6.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Siskiyou 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 ~910 GDD — county provides 1,807 GDD Excellent fit

Scarlet Runner Beans Planting Timeline — Siskiyou County, CA

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 – Apr 10
Transplant Outdoors May 29 May 29 – Jun 12
Direct Sow May 22 May 22 – Jun 12
Harvest July 31 Jul 31 – Sep 4

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 · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 8a

📆 Growing Season

139 days in Siskiyou County

Growing Tips for Scarlet Runner Beans in Siskiyou County

Direct sow Scarlet Runner Beans outdoors after May 15 in Siskiyou County when soil has warmed and frost danger has passed.

Sandy soil in Siskiyou 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.

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 Siskiyou County, CA?

Siskiyou County is in Zone 8a with an average last frost of May 15. Plan your Scarlet Runner Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Siskiyou County, CA?

Siskiyou County, California is in USDA Hardiness Zone 8a. The average last spring frost is May 15 and first fall frost is October 1.

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Your Siskiyou County Garden Planner — Free

A 24-page printable planner built for Siskiyou County (Zone 8a). 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 Siskiyou County, CA. 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.