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When to Plant Lemon Balm in Island County, WA

Island County, Washington Zone 8b May

May to-do list for Island County, Washington

We've pulled the most time-sensitive tasks for Island County, Washington this May and put them front and centre. Tackle them in order.

Avg. last frost March 30
Avg. first frost November 3
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 15 hrs
June prep starts now
  • First harvests: lemon balm

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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.

Island County, Washington is in USDA Zone 8b. The average last spring frost is March 30 and the first fall frost is November 3, giving you a growing season of approximately 218 days.

At an elevation of 9 feet, Island County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Lemon Balm during the growing season.

Island County, WA (Zone 8b) Long season
218 days
Last Spring Frost March 30
218 growing days
First Fall Frost November 3
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Island County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (102 days to spare)
Transplant: Mar 29 🍅 Harvest: May 31 – Jul 19
Recommended (50%) ✓ Fits season (99 days to spare)
Transplant: Apr 6 🍅 Harvest: Jun 8 – Jul 27
Safe Start (90%) ✓ Fits season (89 days to spare)
Transplant: May 7 🍅 Harvest: Jul 9 – Aug 27

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 Island County

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

Soil pH

Your soil pH (5.6–6.7) is within Lemon Balm's preferred range (5.5–7.5).

Soil Texture

The silt loam soil in Island County is excellent for Lemon Balm — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.3%) — Lemon Balm will thrive.

How to Plant Lemon Balm

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

Succession Planting Lemon Balm

4
successive plantings in your 218-day season

Sow every 6.9 weeks. Last sowing by Aug 25 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/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 6.8" 0" ❄️ Dormant
Feb 4.7" 0" ❄️ Dormant
Mar 2.2" 4.5" 0" ✅ Rainfall sufficient
Apr 2.2" 3.7" 0" ✅ Rainfall sufficient
May 2.2" 2.3" 0" ✅ Rainfall sufficient
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 0.7" 1.5" 🚿 Regular watering
Aug 2.2" 0.8" 1.4" 🚿 Regular watering
Sep 2.2" 1.6" 0.6" 💧 Light watering
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 2.2" 7" 0" ✅ Rainfall sufficient
Dec 7.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Island 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 ~894 GDD — county provides 2,997 GDD Excellent fit

Lemon Balm Planting Timeline — Island County, WA

Lemon Balm Planting Calendar

Activity When Date Range
Transplant Outdoors April 6 Apr 6 – Apr 20
Harvest June 8 Jun 8 – Jul 27

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May
June Harvest
July Harvest
August
September
October
November
December
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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 8b

📆 Growing Season

218 days in Island County

Growing Tips for Lemon Balm in Island County

Direct sow Lemon Balm outdoors after March 30 in Island County when soil has warmed and frost danger has passed.

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 Island County, WA?

Island County is in Zone 8b with an average last frost of March 30. Plan your Lemon Balm planting based on this frost date — see the calendar above for exact timing.

What planting zone is Island County, WA?

Island County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is March 30 and first fall frost is November 3.

🌱

Your Island County Garden Planner — Free

A 24-page printable planner built for Island County (Zone 8b). 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 Island County, WA. 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.