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When to Plant Borage in Canyon County, ID

Canyon County, Idaho Zone 6b April

April in Canyon County, Idaho — your action list

Your Canyon County, Idaho garden is entering a new phase. Here's what's on the schedule for April and why each task matters now.

Avg. last frost May 4
Avg. first frost October 10
Soil temp (4") 38°F
Watering High
Pest pressure Low
Daylight 13.2 hrs
  1. Time to transplant borage

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Direct-sow borage

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

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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.

Canyon County, Idaho is in USDA Zone 6b. The average last spring frost is May 4 and the first fall frost is October 10, giving you a growing season of approximately 159 days.

At an elevation of 4,953 feet, Canyon County receives approximately 13.3 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.

Canyon County, ID (Zone 6b) Moderate season
159 days
Last Spring Frost May 4
159 growing days
First Fall Frost October 10

Canyon County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (68 days to spare)
Start indoors: Mar 16 Transplant: Apr 13 🍅 Harvest: Jun 8 – Jul 27
Recommended (50%) ✓ Fits season (61 days to spare)
Start indoors: Mar 30 Transplant: Apr 27 🍅 Harvest: Jun 22 – Aug 10
Safe Start (90%) ✓ Fits season (44 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 Canyon County

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

Soil pH

Your soil pH (6.2–8.2) is more alkaline than Borage prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). 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 159-day season

Sow every 5.7 weeks. Last sowing by Aug 11 to harvest before frost.

For a dedicated fall crop, sow by Aug 01.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 252 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 0.8" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 2.2" 1.4" 0.8" 💧 Light watering
Jun 2.2" 1.1" 1.1" 🚿 Regular watering
Jul 2.2" 1" 1.2" 🚿 Regular watering
Aug 2.2" 1.6" 0.6" 💧 Light watering
Sep 2.2" 1" 1.2" 🚿 Regular watering
Oct 2.2" 1.1" 1.1" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Canyon 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 2,424 GDD Excellent fit

Borage Planting Timeline — Canyon County, ID

Borage Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors April 27 Apr 27 – May 11
Direct Sow April 20 Apr 20 – May 11
Harvest June 22 Jun 22 – Aug 10
Fall Sowing August 1 Aug 1 – Aug 15

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July 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 6b

📆 Growing Season

159 days in Canyon County

Growing Tips for Borage in Canyon County

Direct sow Borage outdoors after May 04 in Canyon 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 Canyon County, ID?

Canyon County is in Zone 6b with an average last frost of May 4. Plan your Borage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Canyon County, ID?

Canyon County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 4 and first fall frost is October 10.

🌱

Your Canyon County Garden Planner — Free

A 24-page printable planner built for Canyon 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 Canyon County, ID. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.