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When to Plant Lemon Balm in Siskiyou County, CA

Siskiyou County, California Zone 8a May

Your May planting checklist for Siskiyou County, California

May is a pivotal month for Siskiyou County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 15
Avg. first frost October 1
Soil temp (4") 67°F
Watering Critical
Pest pressure Moderate
Daylight 14.3 hrs
  1. Move lemon balm from tray to bed

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

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Lemon balm is a vigorous perennial herb with bright green, lemon-scented leaves. It makes a refreshing tea and is easy to grow but can spread aggressively.

Siskiyou County, California is in USDA Zone 8a. The average last spring frost is May 15 and the first fall frost is October 1, giving you a growing season of approximately 139 days.

At an elevation of 251 feet, Siskiyou County receives approximately 36 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 84°F, so choose short-season varieties of Lemon Balm to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Lemon Balm will need more frequent watering and organic matter to retain nutrients.

Siskiyou County, CA (Zone 8a) Short season
139 days
Last Spring Frost May 15
139 growing days
First Fall Frost October 1

Siskiyou County Soil Profile

Soil Type

Sandy Loam

Soil pH

6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (19 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Sep 2
Recommended (50%) ✓ Fits season (20 days to spare)
Transplant: May 22 🍅 Harvest: Jul 24 – Sep 11
Safe Start (90%) ✓ Fits season (9 days to spare)
Transplant: Jun 25 🍅 Harvest: Aug 27 – Oct 15

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 Siskiyou County

How your county's soil matches Lemon Balm's growing requirements.

Soil pH

Your soil pH (6.0–6.9) is within Lemon Balm's preferred range (5.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Lemon Balm.

How to Plant Lemon Balm

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Lemon Balm

2
successive plantings in your 139-day season

Sow every 6.9 weeks. Last sowing by Jul 23 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Lemon Balm

Lemon Balm 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 Lemon Balm Needs Rainfall You Supplement Action
Jan 7.3" 0" ❄️ Dormant
Feb 7.1" 0" ❄️ Dormant
Mar 5.3" 0" ❄️ Dormant
Apr 3.3" 0" ❄️ Dormant
May 2.2" 1" 1.2" 🚿 Regular 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" 1.6" 0.6" 💧 Light watering
Nov 3.1" 0" ❄️ Dormant
Dec 6.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Siskiyou County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Lemon Balm 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.

Lemon Balm needs ~845 GDD — county provides 1,807 GDD Excellent fit

Lemon Balm Planting Timeline — Siskiyou County, CA

Lemon Balm Planting Calendar

Activity When Date Range
Transplant Outdoors May 22 May 22 – Jun 5
Harvest July 24 Jul 24 – Sep 11

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July Harvest
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–70 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 8a

📆 Growing Season

139 days in Siskiyou County

Growing Tips for Lemon Balm in Siskiyou County

Direct sow Lemon Balm outdoors after May 15 in Siskiyou County when soil has warmed and frost danger has passed.

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

General growing tips

Start from seed, cuttings, or divisions. Contain in pots or use barriers to prevent spreading. Harvest frequently to keep plants bushy and prevent flowering.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemon Balm in Siskiyou County, CA?

Siskiyou County is in Zone 8a with an average last frost of May 15. Plan your Lemon Balm planting based on this frost date — see the calendar above for exact timing.

What planting zone is Siskiyou County, CA?

Siskiyou County, California is in USDA Hardiness Zone 8a. The average last spring frost is May 15 and first fall frost is October 1.

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Your Siskiyou County Garden Planner — Free

A 24-page printable planner built for Siskiyou County (Zone 8a). 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 Siskiyou 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.