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When to Plant Borage in Power County, ID

Power County, Idaho Zone 6a May

Your May planting checklist for Power County, Idaho

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Power County, Idaho.

Avg. last frost May 11
Avg. first frost September 30
Soil temp (4") 40°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Time to transplant borage

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

Get ahead of June
  • Starting indoors: borage
  • First harvests: 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.

Power County, Idaho is in USDA Zone 6a. The average last spring frost is May 11 and the first fall frost is September 30, giving you a growing season of approximately 142 days.

At an elevation of 6,609 feet, Power County receives approximately 14 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Borage during the growing season. With low rainfall, drip irrigation is essential for growing Borage successfully. Mulch heavily to conserve soil moisture.

Power County, ID (Zone 6a) Short season
142 days
Last Spring Frost May 11
142 growing days
First Fall Frost September 30

Power County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (44 days to spare)
Start indoors: Mar 28 Transplant: Apr 25 🍅 Harvest: Jun 20 – Aug 8
Recommended (50%) ✓ Fits season (44 days to spare)
Start indoors: Apr 6 Transplant: May 4 🍅 Harvest: Jun 29 – Aug 17
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: May 7 Transplant: Jun 4 🍅 Harvest: Jul 30 – Sep 17

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 Power County

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

Soil pH

Your soil pH (6.6–8.2) is more alkaline than Borage prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Borage.

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 142-day season

Sow every 5.7 weeks. Last sowing by Aug 01 to harvest before frost.

For a dedicated fall crop, sow by Jul 22.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 130 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 2.2" 1.7" 0.5" 💧 Light watering
Jun 2.2" 0.9" 1.3" 🚿 Regular watering
Jul 2.2" 1.4" 0.8" 💧 Light watering
Aug 2.2" 1.5" 0.7" 💧 Light watering
Sep 2.2" 1.2" 1" 💧 Light watering
Oct 1.3" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Power 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 ~839 GDD — county provides 2,165 GDD Excellent fit

Borage Planting Timeline — Power County, ID

Borage Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 4 May 4 – May 18
Direct Sow April 27 Apr 27 – May 18
Harvest June 29 Jun 29 – Aug 17
Fall Sowing July 22 Jul 22 – Aug 5

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 Harvest
July Fall Sowing Harvest
August Fall Sowing Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

50–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

142 days in Power County

Growing Tips for Borage in Power County

Direct sow Borage outdoors after May 11 in Power 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 Power County, ID?

Power County is in Zone 6a with an average last frost of May 11. Plan your Borage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Power County, ID?

Power County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is May 11 and first fall frost is September 30.

🌱

Your Power County Garden Planner — Free

A 24-page printable planner built for Power County (Zone 6a). 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 Power County, ID. 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.