When to Plant Spinach in Snohomish County, WA
May in Snohomish County, Washington — your action list
A quick May briefing for Snohomish County, Washington gardeners — what's urgent, what's next, and what can wait.
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It's harvest week for spinach
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
Before June arrives, get these ready
- First harvests: spinach
Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.
Snohomish County, Washington is in USDA Zone 8b. The average last spring frost is March 25 and the first fall frost is November 2, giving you a growing season of approximately 222 days.
At an elevation of 230 feet, Snohomish County receives approximately 50.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Spinach during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Spinach root diseases.
Snohomish County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.8
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 Snohomish County
How your county's soil matches Spinach's growing requirements.
Soil pH
Your soil pH (5.7–6.8) is more acidic than Spinach prefers (6.5–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Snohomish County is excellent for Spinach — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.4%) — Spinach will thrive.
How to Plant Spinach
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Spinach
Sow every 4 weeks. Last sowing by Sep 13 to harvest before frost.
For a dedicated fall crop, sow by Aug 24.
Plant Water Budget
Monthly Watering Guide for Spinach
Spinach needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Spinach Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 7.7" | 0" | ❄️ Dormant |
| Feb | — | 5.6" | 0" | ❄️ Dormant |
| Mar | 3" | 5" | 0" | ✅ Rainfall sufficient |
| Apr | 3" | 3.6" | 0" | ✅ Rainfall sufficient |
| May | 3" | 2.6" | 0.4" | 💧 Light watering |
| Jun | 3" | 1.6" | 1.4" | 💧 Light watering |
| Jul | 3" | 0.7" | 2.3" | 🚿 Regular watering |
| Aug | 3" | 1" | 2" | 🚿 Regular watering |
| Sep | 3" | 2" | 1" | 💧 Light watering |
| Oct | 3" | 4.2" | 0" | ✅ Rainfall sufficient |
| Nov | 3" | 8" | 0" | ✅ Rainfall sufficient |
| Dec | — | 8.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Snohomish County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Spinach 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.
Spinach Planting Timeline — Snohomish County, WA
Spinach Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 18 | Feb 18 – Mar 4 |
| Transplant Outdoors | March 25 | Mar 25 – Apr 8 |
| Direct Sow | March 11 | Mar 11 – Apr 1 |
| Harvest | April 29 | Apr 29 – Jul 1 |
| Fall Sowing | August 24 | Aug 24 – Sep 7 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow Harvest |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
35–50 days
🧪 Soil pH
Needs 6.5–7.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 8b
📆 Growing Season
222 days in Snohomish County
Growing Tips for Spinach in Snohomish County
Direct sow Spinach outdoors after March 25 in Snohomish County when soil has warmed and frost danger has passed.
Your generous 222.0-day season in Snohomish County allows multiple plantings of Spinach. Sow every 17.0 days for continuous harvest.
General growing tips
Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.
Recommended Spinach Varieties for Snohomish County
Slow-bolting spinach for warm springs — best as fall crop here
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Wind pollinated — isolate 1/2 mile for purity. Easy to let bolt in heat.
Spinach in Other Locations
Frequently Asked Questions
When should I plant Spinach in Snohomish County, WA?
Snohomish County is in Zone 8b with an average last frost of March 25. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.
What planting zone is Snohomish County, WA?
Snohomish County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is March 25 and first fall frost is November 2.
Your Snohomish County Garden Planner — Free
A 24-page printable planner built for Snohomish 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.