Blog

When to Plant Radish in Wahkiakum County, WA

Wahkiakum County, Washington Zone 8b May

Top priorities for Wahkiakum County, Washington gardeners in May

Your garden in Wahkiakum County, Washington is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 13
Avg. first frost November 4
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.8 hrs
  1. Collect radish at their peak

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Instant PDF download. No spam, unsubscribe any time.

Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.

Wahkiakum County, Washington is in USDA Zone 8b. The average last spring frost is April 13 and the first fall frost is November 4, giving you a growing season of approximately 205 days.

At an elevation of 180 feet, Wahkiakum County receives approximately 35.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Radish during the growing season.

Wahkiakum County, WA (Zone 8b) Long season
205 days
Last Spring Frost April 13
205 growing days
First Fall Frost November 4

Wahkiakum County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (161 days to spare)
Transplant: Apr 2 🍅 Harvest: Apr 30 – May 21
Recommended (50%) ✓ Fits season (156 days to spare)
Transplant: Apr 13 🍅 Harvest: May 11 – Jun 1
Safe Start (90%) ✓ Fits season (168 days to spare)
Transplant: Apr 30 🍅 Harvest: May 28 – Jun 18

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 Wahkiakum County

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

Soil pH

Your soil pH (5.4–6.3) is more acidic than Radish prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.6%) — Radish will thrive.

How to Plant Radish

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Radish

11
successive plantings in your 205-day season

Sow every 2.4 weeks. Last sowing by Sep 30 to harvest before frost.

For a dedicated fall crop, sow by Aug 26.

Plant Water Budget

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

Monthly Watering Guide for Radish

Radish 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 Radish Needs Rainfall You Supplement Action
Jan 4.9" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 3.6" 0" ❄️ Dormant
Apr 2.2" 2.6" 0" ✅ Rainfall sufficient
May 2.2" 1.8" 0.4" 💧 Light watering
Jun 2.2" 1.4" 0.8" 💧 Light watering
Jul 2.2" 0.6" 1.6" 🚿 Regular watering
Aug 2.2" 0.7" 1.5" 🚿 Regular watering
Sep 2.2" 1.4" 0.8" 💧 Light watering
Oct 2.2" 2.9" 0" ✅ Rainfall sufficient
Nov 2.2" 5.8" 0" ✅ Rainfall sufficient
Dec 5.3" 0" ❄️ Dormant

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

Radish 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.

Radish needs ~392 GDD — county provides 2,818 GDD Excellent fit

Radish Planting Timeline — Wahkiakum County, WA

Radish Planting Calendar

Activity When Date Range
Direct Sow March 30 Mar 30 – Apr 20
Harvest April 27 Apr 27 – May 18
Fall Sowing August 26 Aug 26 – Sep 9

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

205 days in Wahkiakum County

Growing Tips for Radish in Wahkiakum County

Direct sow Radish outdoors after April 13 in Wahkiakum County when soil has warmed and frost danger has passed.

Your generous 205.0-day season in Wahkiakum County allows multiple plantings of Radish. Sow every 11.0 days for continuous harvest.

Common pests for Radish in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radish in Wahkiakum County, WA?

Wahkiakum County is in Zone 8b with an average last frost of April 13. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Wahkiakum County, WA?

Wahkiakum County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 13 and first fall frost is November 4.

🌱

Your Wahkiakum County Garden Planner — Free

A 24-page printable planner built for Wahkiakum 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 Wahkiakum 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.