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When to Plant Borage in Okanogan County, WA

Okanogan County, Washington Zone 6b May

Okanogan County, Washington gardeners: here's your May plan

A quick May briefing for Okanogan County, Washington gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 13
Avg. first frost September 26
Soil temp (4") 49°F
Watering High
Pest pressure Low
Daylight 15 hrs
  1. Transplant borage outside

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

Get ahead of June
  • Starting indoors: borage

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Borage is a self-seeding annual herb with star-shaped blue flowers that attract pollinators. Its leaves have a cucumber-like flavor and the flowers are edible.

Okanogan County, Washington is in USDA Zone 6b. The average last spring frost is May 13 and the first fall frost is September 26, giving you a growing season of approximately 136 days.

At an elevation of 3,788 feet, Okanogan County receives approximately 21.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Borage to ensure they mature before fall.

Okanogan County, WA (Zone 6b) Short season
136 days
Last Spring Frost May 13
136 growing days
First Fall Frost September 26

Okanogan County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Start indoors: Apr 3 Transplant: May 1 🍅 Harvest: Jun 26 – Aug 14
Recommended (50%) ✓ Fits season (38 days to spare)
Start indoors: Apr 8 Transplant: May 6 🍅 Harvest: Jul 1 – Aug 19
Safe Start (90%) ✓ Fits season (34 days to spare)
Start indoors: May 2 Transplant: May 30 🍅 Harvest: Jul 25 – Sep 12

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 Okanogan County

How your county's soil matches Borage's growing requirements.

Soil pH

Your soil pH (5.4–6.5) is more acidic than Borage prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Okanogan County is excellent for Borage — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Borage.

Organic Matter

Organic matter is excellent (5.6%) — Borage will thrive.

How to Plant Borage

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Borage

3
successive plantings in your 136-day season

Sow every 5.7 weeks. Last sowing by Jul 28 to harvest before frost.

For a dedicated fall crop, sow by Jul 18.

Plant Water Budget

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

Monthly Watering Guide for Borage

Borage needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Borage Needs Rainfall You Supplement Action
Jan 2.9" 0" ❄️ Dormant
Feb 2.4" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 2.2" 1.3" 0.9" 💧 Light watering
Jun 2.2" 0.7" 1.5" 🚿 Regular watering
Jul 2.2" 0.3" 1.9" 🚿 Regular watering
Aug 2.2" 0.4" 1.8" 🚿 Regular watering
Sep 2.2" 0.7" 1.5" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 3.6" 0" ❄️ Dormant
Dec 3.7" 0" ❄️ Dormant

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

Borage 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.

Borage needs ~674 GDD — county provides 1,666 GDD Excellent fit

Borage Planting Timeline — Okanogan County, WA

Borage Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 29 Apr 29 – May 20
Harvest July 1 Jul 1 – Aug 19
Fall Sowing July 18 Jul 18 – Aug 1

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

50–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

136 days in Okanogan County

Growing Tips for Borage in Okanogan County

Direct sow Borage outdoors after May 13 in Okanogan County when soil has warmed and frost danger has passed.

General growing tips

Direct sow in spring as borage does not transplant well. Allow some plants to go to seed for next year. Young leaves are best; older leaves become bristly.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Borage in Okanogan County, WA?

Okanogan County is in Zone 6b with an average last frost of May 13. Plan your Borage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Okanogan County, WA?

Okanogan County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is May 13 and first fall frost is September 26.

🌱

Your Okanogan County Garden Planner — Free

A 24-page printable planner built for Okanogan County (Zone 6b). 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 Okanogan County, WA. 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.