When to Plant Spinach in Pierce County, WA
This month in Pierce County, Washington
May is a pivotal month for Pierce County, Washington gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Start spinach under lights
Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.
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It's harvest week for spinach
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
June will be here before you know it — start on
- 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.
Pierce County, Washington is in USDA Zone 8b. The average last spring frost is April 13 and the first fall frost is October 30, giving you a growing season of approximately 200 days.
At an elevation of 168 feet, Pierce County receives approximately 48.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Spinach to ensure they mature before fall.
Pierce County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.2
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 Pierce County
How your county's soil matches Spinach's growing requirements.
Soil pH
Your soil pH (5.4–6.2) is more acidic than Spinach prefers (6.5–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Pierce County is excellent for Spinach — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.4%) — 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 10 to harvest before frost.
For a dedicated fall crop, sow by Aug 21.
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 | — | 6.8" | 0" | ❄️ Dormant |
| Feb | — | 5.7" | 0" | ❄️ Dormant |
| Mar | — | 4.4" | 0" | ❄️ Dormant |
| Apr | 3" | 4.1" | 0" | ✅ Rainfall sufficient |
| May | 3" | 2.8" | 0.2" | 💧 Light watering |
| Jun | 3" | 2" | 1" | 💧 Light watering |
| Jul | 3" | 0.9" | 2.1" | 🚿 Regular watering |
| Aug | 3" | 0.9" | 2.1" | 🚿 Regular watering |
| Sep | 3" | 2" | 1" | 💧 Light watering |
| Oct | 3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Nov | — | 7.8" | 0" | ❄️ Dormant |
| Dec | — | 6.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Pierce 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 — Pierce County, WA
Spinach Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 9 | Mar 9 – Mar 23 |
| Transplant Outdoors | April 13 | Apr 13 – Apr 27 |
| Direct Sow | March 30 | Mar 30 – Apr 20 |
| Harvest | May 18 | May 18 – Jul 20 |
| Fall Sowing | August 21 | Aug 21 – Sep 4 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| 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
200 days in Pierce County
Growing Tips for Spinach in Pierce County
Direct sow Spinach outdoors after April 13 in Pierce County when soil has warmed and frost danger has passed.
Your generous 200.0-day season in Pierce 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.
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 Pierce County, WA?
Pierce County is in Zone 8b with an average last frost of April 13. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.
What planting zone is Pierce County, WA?
Pierce County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 13 and first fall frost is October 30.
Your Pierce County Garden Planner — Free
A 24-page printable planner built for Pierce 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.