When to Plant Arugula in Asotin County, WA
May in Asotin County, Washington — your action list
Here's what deserves your attention in Asotin County, Washington this month. Everything below is tailored to Zone 7a and timed around your local frost dates.
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Move arugula from tray to bed
Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.
A few tasks this May that'll pay off in June
- Starting indoors: arugula
- First harvests: arugula
Arugula is a fast-growing cool-season green with a peppery, nutty flavor. It is excellent in salads and can be harvested as baby greens or mature leaves.
Asotin County, Washington is in USDA Zone 7a. 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 85°F, providing good warmth for Arugula during the growing season. With low rainfall, drip irrigation is essential for growing Arugula successfully. Mulch heavily to conserve soil moisture.
Asotin County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.5
Drainage
Well Drained
Plant Planting Risk Windows
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 Arugula's growing requirements.
Soil pH
Your soil pH (5.5–6.5) overlaps with Arugula's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Asotin County is excellent for Arugula — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — Arugula will thrive.
How to Plant Arugula
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Arugula
Sow every 3.4 weeks. Last sowing by Aug 11 to harvest before frost.
For a dedicated fall crop, sow by Jul 22.
Plant Water Budget
Monthly Watering Guide for Arugula
Arugula needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.
| Month | Arugula Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | — | 0.9" | 0" | ❄️ Dormant |
| May | 2.6" | 0.8" | 1.8" | 🚿 Regular watering |
| Jun | 2.6" | 0.6" | 2" | 🚿 Regular watering |
| Jul | 2.6" | 0.2" | 2.4" | 🚿 Regular watering |
| Aug | 2.6" | 0.3" | 2.3" | 🚿 Regular watering |
| Sep | 2.6" | 0.5" | 2.1" | 🚿 Regular watering |
| Oct | — | 1.2" | 0" | ❄️ Dormant |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Asotin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Arugula 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.
Arugula Planting Timeline — Asotin County, WA
Arugula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 4 | Apr 4 – Apr 18 |
| Transplant Outdoors | May 9 | May 9 – May 23 |
| Direct Sow | April 25 | Apr 25 – May 16 |
| Harvest | June 13 | Jun 13 – Aug 15 |
| Fall Sowing | July 22 | Jul 22 – Aug 5 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Fall Sowing Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.6"/week · Only during dry spells
📅 Days to Maturity
30–50 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
144 days in Asotin County
Growing Tips for Arugula in Asotin County
Direct sow Arugula outdoors after May 09 in Asotin County when soil has warmed and frost danger has passed.
Your generous 144.0-day season in Asotin County allows multiple plantings of Arugula. Sow every 15.0 days for continuous harvest.
Common pests for Arugula in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Sow seeds directly every 2-3 weeks for continuous harvest. Provide afternoon shade in warm weather to prevent bolting. Harvest outer leaves first to extend production.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Arugula in Other Locations
Frequently Asked Questions
When should I plant Arugula in Asotin County, WA?
Asotin County is in Zone 7a with an average last frost of May 9. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.
What planting zone is Asotin County, WA?
Asotin County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is May 9 and first fall frost is September 30.
Your Asotin County Garden Planner — Free
A 24-page printable planner built for Asotin 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.