Blog

When to Plant Lemon Balm in Yakima County, WA

Yakima County, Washington Zone 7a May

May to-do list for Yakima County, Washington

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

Avg. last frost May 6
Avg. first frost October 3
Soil temp (4") 54°F
Watering Critical
Pest pressure Low
Daylight 14.8 hrs
  1. Harden off and plant lemon balm

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

Instant PDF download. No spam, unsubscribe any time.

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.

Yakima County, Washington is in USDA Zone 7a. The average last spring frost is May 6 and the first fall frost is October 3, giving you a growing season of approximately 150 days.

At an elevation of 3,150 feet, Yakima County receives approximately 18 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Lemon Balm during the growing season. With low rainfall, drip irrigation is essential for growing Lemon Balm successfully. Mulch heavily to conserve soil moisture.

Yakima County, WA (Zone 7a) Moderate season
150 days
Last Spring Frost May 6
150 growing days
First Fall Frost October 3
Share this guide:

Yakima County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Transplant: May 7 🍅 Harvest: Jul 9 – Aug 27
Recommended (50%) ✓ Fits season (31 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Sep 2
Safe Start (90%) ✓ Fits season (28 days to spare)
Transplant: Jun 2 🍅 Harvest: Aug 4 – Sep 22

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 Yakima County

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

Soil pH

Your soil pH (5.5–6.3) is within Lemon Balm's preferred range (5.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) — Lemon Balm will thrive.

How to Plant Lemon Balm

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

Succession Planting Lemon Balm

2
successive plantings in your 150-day season

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

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/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 2.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 2.2" 1" 1.2" 🚿 Regular watering
Jun 2.2" 0.6" 1.6" 🚿 Regular watering
Jul 2.2" 0.3" 1.9" 🚿 Regular watering
Aug 2.2" 0.3" 1.9" 🚿 Regular watering
Sep 2.2" 0.6" 1.6" 🚿 Regular watering
Oct 2.2" 1.4" 0.8" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 3.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Yakima 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 ~942 GDD — county provides 2,175 GDD Excellent fit

Lemon Balm Planting Timeline — Yakima County, WA

Lemon Balm Planting Calendar

Activity When Date Range
Transplant Outdoors May 13 May 13 – May 27
Harvest July 15 Jul 15 – Sep 2

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

Month-by-Month Timeline

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

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 7a

📆 Growing Season

150 days in Yakima County

Growing Tips for Lemon Balm in Yakima County

Direct sow Lemon Balm outdoors after May 06 in Yakima 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 Yakima County, WA?

Yakima County is in Zone 7a with an average last frost of May 6. Plan your Lemon Balm planting based on this frost date — see the calendar above for exact timing.

What planting zone is Yakima County, WA?

Yakima County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is May 6 and first fall frost is October 3.

🌱

Your Yakima County Garden Planner — Free

A 24-page printable planner built for Yakima County (Zone 7a). 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 Yakima 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.