When to Plant Arugula in Okanogan County, WA
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.
Okanogan County, Washington is in USDA Zone 5b. The average last spring frost is May 13 and the first fall frost is September 26, giving you a growing season of approximately 136 days.
At an elevation of 3,788 feet, Okanogan County receives approximately 21.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Arugula to ensure they mature before fall.
Okanogan County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.5
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 Okanogan County
How your county's soil matches Arugula's growing requirements.
Soil pH
Your soil pH (5.4–6.5) is more acidic than Arugula prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Okanogan County is excellent for Arugula — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Arugula.
Organic Matter
Organic matter is excellent (5.6%) — 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 07 to harvest before frost.
For a dedicated fall crop, sow by Jul 18.
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 | — | 2.9" | 0" | ❄️ Dormant |
| Feb | — | 2.4" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | — | 1.4" | 0" | ❄️ Dormant |
| May | 2.6" | 1.3" | 1.3" | 🚿 Regular watering |
| Jun | 2.6" | 0.7" | 1.9" | 🚿 Regular watering |
| Jul | 2.6" | 0.3" | 2.3" | 🚿 Regular watering |
| Aug | 2.6" | 0.4" | 2.2" | 🚿 Regular watering |
| Sep | 2.6" | 0.7" | 1.9" | 🚿 Regular watering |
| Oct | — | 1.7" | 0" | ❄️ Dormant |
| Nov | — | 3.6" | 0" | ❄️ Dormant |
| Dec | — | 3.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Okanogan 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 — Okanogan County, WA
Arugula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 8 | Apr 8 – Apr 22 |
| Transplant Outdoors | May 13 | May 13 – May 27 |
| Direct Sow | April 29 | Apr 29 – May 20 |
| Harvest | June 17 | Jun 17 – Aug 19 |
| Fall Sowing | July 18 | Jul 18 – Aug 1 |
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: too_acidic
🗺️ USDA Zone
Zone 5b
📆 Growing Season
136 days in Okanogan County
Growing Tips for Arugula in Okanogan County
Direct sow Arugula outdoors after May 13 in Okanogan County when soil has warmed and frost danger has passed.
Your generous 136.0-day season in Okanogan 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
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Arugula in Other Locations
Frequently Asked Questions
When should I plant Arugula in Okanogan County, WA?
Okanogan County is in Zone 5b with an average last frost of May 13. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.
What planting zone is Okanogan County, WA?
Okanogan County, Washington is in USDA Hardiness Zone 5b. The average last spring frost is May 13 and first fall frost is September 26.
Plan Your Garden with Confidence
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