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When to Plant Borage in Shasta County, CA

Shasta County, California Zone 9a April

This month in Shasta County, California

Here's what deserves your attention in Shasta County, California this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost June 6
Avg. first frost September 21
Soil temp (4") 60°F
Watering Moderate
Pest pressure High
Daylight 13.1 hrs
May prep starts now
  • Transplants going out: borage
  • Direct-sowing: 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.

Shasta County, California is in USDA Zone 9a. The average last spring frost is June 6 and the first fall frost is September 21, giving you a growing season of approximately 107 days.

At an elevation of 81 feet, Shasta County receives approximately 40.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 85°F, providing good warmth for Borage during the growing season. Sandy soil warms quickly in spring — great for early planting — but Borage will need more frequent watering and organic matter to retain nutrients.

Shasta County, CA (Zone 9a) Short season
107 days
Last Spring Frost June 6
107 growing days
First Fall Frost September 21
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Shasta County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Apr 25 Transplant: May 16 🍅 Harvest: Jul 11 – Aug 29
Recommended (50%) ✓ Fits season (9 days to spare)
Start indoors: May 9 Transplant: May 30 🍅 Harvest: Jul 25 – Sep 12
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: May 25 Transplant: Jun 15 🍅 Harvest: Aug 10 – Sep 28

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 Shasta County

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Borage's range (6.0–7.0), though not a perfect match.

Soil Texture

Sandy soil in Shasta County warms quickly in spring but drains fast. Borage will need more frequent watering and regular compost additions to retain nutrients.

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 8 weeks before your first frost date for a fall harvest.

Succession Planting Borage

2
successive plantings in your 107-day season

Sow every 5.7 weeks. Last sowing by Jul 23 to harvest before frost.

For a dedicated fall crop, sow by Jul 27.

Plant Water Budget

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

Water stress score is 8/10 — 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 7.7" 0" ❄️ Dormant
Feb 8" 0" ❄️ Dormant
Mar 6.8" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 1" 0" ❄️ Dormant
Jun 2.2" 0.2" 2" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.4" 1.8" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 4.4" 0" ❄️ Dormant
Dec 7.1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Shasta 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 ~756 GDD — county provides 1,471 GDD Excellent fit

Borage Planting Timeline — Shasta County, CA

Borage Planting Calendar

Activity When Date Range
Start Indoors May 9 May 9 – May 23
Transplant Outdoors May 30 May 30 – Jun 13
Direct Sow May 16 May 16 – Jun 6
Harvest July 25 Jul 25 – Sep 12
Fall Sowing July 27 Jul 27 – Aug 10

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 Fall Sowing Harvest
September Harvest
October
November
December
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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: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

107 days in Shasta County

Growing Tips for Borage in Shasta County

Direct sow Borage outdoors after June 06 in Shasta County when soil has warmed and frost danger has passed.

Sandy soil in Shasta County dries quickly — mulch Borage with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

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 Shasta County, CA?

Shasta County is in Zone 9a 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 Shasta County, CA?

Shasta County, California is in USDA Hardiness Zone 9a. The average last spring frost is June 6 and first fall frost is September 21.

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Your Shasta County Garden Planner — Free

A 24-page printable planner built for Shasta County (Zone 9a). 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 Shasta County, CA. 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.