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When to Plant Purslane in Asotin County, WA

Purslane is a succulent edible plant rich in omega-3 fatty acids, often considered a weed but increasingly valued as a nutritious green. It has a lemony, peppery flavor.

Asotin County, Washington is in USDA Zone 6b. The average last spring frost is May 9 and the first fall frost is September 30, giving you a growing season of approximately 144 days.

At an elevation of 2,029 feet, Asotin County receives approximately 14 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Purslane during the growing season. With low rainfall, drip irrigation is essential for growing Purslane successfully. Mulch heavily to conserve soil moisture.

Asotin County, WA (Zone 6b) Short season
144 days
Last Spring Frost May 9
144 growing days
First Fall Frost September 30

Asotin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jun 9 – Jul 14
Recommended (50%) ✓ Fits season (67 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jun 20 – Jul 25
Safe Start (90%) ✓ Fits season (60 days to spare)
Start indoors: May 2 Transplant: Jun 6 🍅 Harvest: Jul 18 – Aug 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 Asotin County

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

Soil pH

Your soil pH (5.5โ€“6.5) is within Purslane's preferred range (5.5โ€“7.5).

Soil Texture

The silt loam soil in Asotin County is excellent for Purslane โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.7%) โ€” Purslane will thrive.

How to Plant Purslane

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Succession Planting Purslane

4
successive plantings in your 144-day season

Sow every 4.6 weeks. Last sowing by Aug 01 to harvest before frost.

For a dedicated fall crop, sow by Jul 22.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 117 gal / 100 sq ft

Monthly Watering Guide for Purslane

Purslane 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 Purslane Needs Rainfall You Supplement Action
Jan โ€” 2" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 1.5" 0" โ„๏ธ Dormant
Apr โ€” 0.9" 0" โ„๏ธ Dormant
May 2.2" 0.8" 1.4" ๐Ÿšฟ Regular watering
Jun 2.2" 0.6" 1.6" ๐Ÿšฟ Regular watering
Jul 2.2" 0.2" 2" ๐Ÿšฟ Regular watering
Aug 2.2" 0.3" 1.9" ๐Ÿšฟ Regular watering
Sep 2.2" 0.5" 1.7" ๐Ÿšฟ Regular watering
Oct โ€” 1.2" 0" โ„๏ธ Dormant
Nov โ€” 2.4" 0" โ„๏ธ Dormant
Dec โ€” 1.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Asotin County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Purslane 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" โ€” every day above 50ยฐF 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.

Purslane needs ~688 GDD — county provides 1,980 GDD Excellent fit

Purslane Planting Timeline โ€” Asotin County, WA

Purslane Planting Calendar

Activity When Date Range
Start Indoors April 4 Apr 4 โ€“ Apr 18
Transplant Outdoors May 9 May 9 โ€“ May 23
Direct Sow April 25 Apr 25 โ€“ May 16
Harvest June 20 Jun 20 โ€“ Jul 25
Fall Sowing July 22 Jul 22 โ€“ Aug 5

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

40โ€“60 days

๐Ÿงช Soil pH

Needs 5.5โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

144 days in Asotin County

Growing Tips for Purslane in Asotin County

Direct sow Purslane outdoors after May 09 in Asotin County when soil has warmed and frost danger has passed.

Asotin County receives only 14" of rain annually. Purslane needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost or allow to self-seed. Purslane thrives in hot, dry conditions. Harvest stem tips regularly. Contains more omega-3 fatty acids than any other leafy green.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Purslane in Asotin County, WA?

Asotin County is in Zone 6b with an average last frost of May 9. Plan your Purslane planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Asotin County, WA?

Asotin County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is May 9 and first fall frost is September 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Asotin County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Asotin County, WA. Local conditions may vary. Last updated: April 2026.