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When to Plant Tomatoes in Clark County, WA

Tomatoes

Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

Clark County, Washington is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 27, giving you a growing season of approximately 196 days.

At an elevation of 482 feet, Clark County receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Tomatoes during the growing season.

Clark County, WA (Zone 8b) Moderate season
196 days
Last Spring Frost April 14
196 growing days
First Fall Frost October 27

Clark County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.3

Drainage

Well Drained

How Much Tomatoes to Grow

10-15 lbs
Average yield per plant
3
Plants per person
6 sq ft
Space per person

For a family of 4, plant approximately 12 tomatoes plants in about 24 sq ft. In Clark County's 196-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Monthly Watering Guide for Tomatoes

Tomatoes needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Tomatoes Needs Rainfall You Supplement Action
Jan 5.4" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 4" 0" ❄️ Dormant
Apr 4.3" 2.6" 1.7" 💧 Light watering
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 0.6" 3.7" 🚿 Regular watering
Aug 4.3" 0.8" 3.5" 🚿 Regular watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 5.9" 0" ❄️ Dormant
Dec 7.2" 0" ❄️ Dormant

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

Tomatoes Planting Timeline — Clark County, WA

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors April 28 Apr 28 – May 12
Direct Sow April 21 Apr 21 – May 12
Harvest June 30 Jun 30 – Sep 8

Plant 0.5" deep · 24" apart · Rows 36" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 8b

📆 Growing Season

196 days in Clark County

Growing Tips for Clark County

Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35°F, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Clark County, WA?

Clark County is in Zone 8b with an average last frost of April 14. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, WA?

Clark County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 27.

🌱

Your Clark County Garden Planner — Free

A 22-page printable planner built for Clark 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.

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 Clark County, WA. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.