Blog

When to Plant Borage in Tehama County, CA

Tehama County, California Zone 9b May

May in the garden — Tehama County, California

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

Avg. last frost March 6
Avg. first frost November 28
Soil temp (4") 72°F
Watering High
Pest pressure High
Daylight 14.2 hrs
  1. Pick borage

    If you can't use it all right away, check the food-preservation section of your planner.

Coming up in June — start thinking about
  • First harvests: borage

Instant PDF download. No spam, unsubscribe any time.

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.

Tehama County, California is in USDA Zone 9b. The average last spring frost is March 6 and the first fall frost is November 28, giving you a growing season of approximately 267 days.

At an elevation of 78 feet, Tehama County receives approximately 44 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Borage to ensure they mature before fall.

Tehama County, CA (Zone 9b) Long season
267 days
Last Spring Frost March 6
267 growing days
First Fall Frost November 28

Tehama County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (172 days to spare)
Start indoors: Jan 26 Transplant: Feb 16 🍅 Harvest: Apr 13 – Jun 1
Recommended (50%) ✓ Fits season (169 days to spare)
Start indoors: Feb 6 Transplant: Feb 27 🍅 Harvest: Apr 24 – Jun 12
Safe Start (90%) ✓ Fits season (147 days to spare)
Start indoors: Mar 21 Transplant: Apr 11 🍅 Harvest: Jun 6 – Jul 25

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 Tehama County

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

Soil pH

Your soil pH (6.8–7.6) is more alkaline than Borage prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). 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

6
successive plantings in your 267-day season

Sow every 5.7 weeks. Last sowing by Sep 29 to harvest before frost.

For a dedicated fall crop, sow by Oct 03.

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
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 10.2" 0" ❄️ Dormant
Feb 8.5" 0" ❄️ Dormant
Mar 2.2" 7" 0" ✅ Rainfall sufficient
Apr 2.2" 3.5" 0" ✅ Rainfall sufficient
May 2.2" 1.3" 0.9" 💧 Light watering
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 2.2" 1.8" 0.4" 💧 Light watering
Nov 2.2" 4.2" 0" ✅ Rainfall sufficient
Dec 6.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Tehama 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 ~632 GDD — county provides 3,070 GDD Excellent fit

Borage Planting Timeline — Tehama County, CA

Borage Planting Calendar

Activity When Date Range
Start Indoors February 6 Feb 6 – Feb 20
Transplant Outdoors February 27 Feb 27 – Mar 13
Direct Sow February 13 Feb 13 – Mar 6
Harvest April 24 Apr 24 – Jun 12
Fall Sowing October 3 Oct 3 – Oct 17

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 9b

📆 Growing Season

267 days in Tehama County

Growing Tips for Borage in Tehama County

Direct sow Borage outdoors after March 06 in Tehama 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 Tehama County, CA?

Tehama County is in Zone 9b with an average last frost of March 6. Plan your Borage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tehama County, CA?

Tehama County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 6 and first fall frost is November 28.

🌱

Your Tehama County Garden Planner — Free

A 24-page printable planner built for Tehama County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Tehama County, CA. 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.