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When to plant Borage in Foothill Ranch, CA

The best window to plant Borage in Foothill Ranch, is January 23–February 13, when soil warms to 50°F. Last frost typically hits February 13; first frost December 11. A second sowing from October 16 to October 30 extends the harvest into fall.

When to Plant Borage in Foothill Ranch, CA

Orange County, California Zone 10b June

This month in Orange County, California

We've pulled the most time-sensitive tasks for Orange County, California this June and put them front and centre. Tackle them in order.

Avg. last frost February 13
Avg. first frost December 11
Soil temp (4") 86°F
Watering Critical
Pest pressure High
Daylight 14.2 hrs
  1. Survive, don't thrive

    June-August is endurance gardening. Keep okra, peppers, sweet potatoes, and southern peas alive. Harvest everything daily before the heat damages produce on the vine.

  2. Start fall tomato seeds indoors

    Yes, indoors — under lights or in AC. They'll be ready to transplant in August when temperatures briefly moderate.

  3. Add compost to empty beds

    Empty beds get a thick layer of compost + mulch to suppress weeds and feed the soil for fall planting.

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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.

Foothill Ranch, California is in USDA Zone 10b. The average last spring frost is February 13 and the first fall frost is December 11, giving you a growing season of approximately 301 days.

At an elevation of 405 feet, Orange County receives approximately 13.8 inches of rainfall annually with predominantly loam soil. Summer highs average 88°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.

Foothill Ranch, CA (Zone 10b) Year-round
301 days
Last Spring Frost February 13
301 growing days
First Fall Frost December 11

Foothill Ranch Soil Profile

Soil Type

Loam

Soil pH

5.7-7.6

Drainage

Well Drained

Borage Planting Risk Windows

Early Start (70% safe) ✓ Fits season (202 days to spare)
Start indoors: Jan 5 Transplant: Jan 26 🍅 Harvest: Mar 23 – May 11
Recommended (50%) ✓ Fits season (203 days to spare)
Start indoors: Jan 16 Transplant: Feb 6 🍅 Harvest: Apr 3 – May 22
Safe Start (90%) ✓ Fits season (164 days to spare)
Start indoors: Mar 5 Transplant: Mar 26 🍅 Harvest: May 21 – Jul 9

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 Foothill Ranch

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

Soil pH

Your soil pH (5.7–7.6) overlaps with Borage's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). 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

7
successive plantings in your 301-day season

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

For a dedicated fall crop, sow by Oct 16.

Borage Water Budget

Plant needs
0.5″/week
Rainfall provides
0.2″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 994 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 2.4" 0" ❄️ Dormant
Feb 2.2" 2.6" 0" ✅ Rainfall sufficient
Mar 2.2" 2.2" 0" ✅ Rainfall sufficient
Apr 2.2" 1.1" 1.1" 🚿 Regular watering
May 2.2" 0.4" 1.8" 🚿 Regular watering
Jun 2.2" 0.1" 2.1" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.2" 2" 🚿 Regular watering
Oct 2.2" 0.7" 1.5" 🚿 Regular watering
Nov 2.2" 1.5" 0.7" 💧 Light watering
Dec 2.2" 2.7" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Orange 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 ~880 GDD — county provides 4,832 GDD Excellent fit

Borage Planting Timeline — Foothill Ranch, CA

Borage Planting Calendar

Activity When Date Range
Start Indoors January 16 Jan 16 – Jan 30
Transplant Outdoors February 6 Feb 6 – Feb 20
Direct Sow January 23 Jan 23 – Feb 13
Harvest April 3 Apr 3 – May 22
Fall Sowing October 16 Oct 16 – Oct 30

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

50–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 10b

📆 Growing Season

301 days in Orange County

Growing Tips for Borage in Foothill Ranch

Direct sow Borage outdoors after February 13 in Orange 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 →

When should I plant Borage in Foothill Ranch, CA?

In Foothill Ranch, CA, plant Borage after the last frost (around February 13) and before the first frost (around December 11). Best results when soil holds above 50°F.

What growing zone is Foothill Ranch, CA for Borage?

Foothill Ranch sits in USDA Zone 10b. Borage grows reliably in zones 3a through 11b, so it's a good fit here.

Can Borage grow in Foothill Ranch's climate?

Yes — Borage grows well in Foothill Ranch's temperate climate. Foothill Ranch averages a 302-day frost-free season, with last frost around February 13 and first frost around December 11.

🌱

Your Orange County Garden Planner — Free

A 22-page printable planner built for Orange County (Zone 10b). 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 Orange County, CA. Local conditions may vary. Last updated: June 2026.