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When to Plant Borage in Grant County, OR

Grant County, Oregon Zone 6b May

Top priorities for Grant County, Oregon gardeners in May

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

Avg. last frost June 6
Avg. first frost September 10
Soil temp (4") 51°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
  1. Move borage from tray to bed

    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. Plant borage from seed, right in the garden

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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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.

Grant County, Oregon is in USDA Zone 6b. The average last spring frost is June 6 and the first fall frost is September 10, giving you a growing season of approximately 96 days.

At an elevation of 2,838 feet, Grant County receives approximately 22.6 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.

Grant County, OR (Zone 6b) Very short season
96 days
Last Spring Frost June 6
96 growing days
First Fall Frost September 10

Grant County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 15 Transplant: May 13 🍅 Harvest: Jul 8 – Aug 26
Recommended (50%) ✗ May not fit
Start indoors: May 2 Transplant: May 30 🍅 Harvest: Jul 25 – Sep 12
Safe Start (90%) ✓ Fits season (2 days to spare)
Start indoors: May 22 Transplant: Jun 19 🍅 Harvest: Aug 14 – Oct 2

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 Grant County

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

Soil pH

Your soil pH (5.4–6.4) is more acidic than Borage prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Grant 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 (4.8%) — 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

2
successive plantings in your 96-day season

Sow every 5.7 weeks. Last sowing by Jul 12 to harvest before frost.

For a dedicated fall crop, sow by Jul 02.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/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 3.2" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 1.3" 0" ❄️ Dormant
Jun 2.2" 0.8" 1.4" 🚿 Regular watering
Jul 2.2" 0.4" 1.8" 🚿 Regular watering
Aug 2.2" 0.4" 1.8" 🚿 Regular watering
Sep 2.2" 0.9" 1.3" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 3.1" 0" ❄️ Dormant
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Grant 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 1,176 GDD Excellent fit

Borage Planting Timeline — Grant County, OR

Borage Planting Calendar

Activity When Date Range
Start Indoors May 2 May 2 – May 16
Transplant Outdoors May 30 May 30 – Jun 13
Direct Sow May 23 May 23 – Jun 13
Harvest July 25 Jul 25 – Sep 12
Fall Sowing July 2 Jul 2 – Jul 16

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

Month-by-Month Timeline

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

96 days in Grant County

Growing Tips for Borage in Grant County

Direct sow Borage outdoors after June 06 in Grant 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 Grant County, OR?

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

What planting zone is Grant County, OR?

Grant County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is June 6 and first fall frost is September 10.

🌱

Your Grant County Garden Planner — Free

A 24-page printable planner built for Grant 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 Grant County, OR. 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.