When to Plant Spinach in King County, TX
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.
King County, Texas is in USDA Zone 7b. The average last spring frost is March 31 and the first fall frost is November 7, giving you a growing season of approximately 221 days.
At an elevation of 3,170 feet, King County receives approximately 60.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 99°F, so Spinach may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Spinach will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Spinach root diseases.
King County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.8-8.4
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 King County
How your county's soil matches Spinach's growing requirements.
Soil pH
Your soil pH (7.8–8.4) is more alkaline than Spinach prefers (6.5–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in King County warms quickly in spring but drains fast. Spinach will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is low (1.1%). Add 2-3 inches of compost before planting Spinach.
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 18 to harvest before frost.
For a dedicated fall crop, sow by Aug 29.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 4.7" | 0" | ❄️ Dormant |
| Feb | — | 3.2" | 0" | ❄️ Dormant |
| Mar | 3" | 3.9" | 0" | ✅ Rainfall sufficient |
| Apr | 3" | 2.3" | 0.7" | 💧 Light watering |
| May | 3" | 1.5" | 1.5" | 🚿 Regular watering |
| Jun | 3" | 2.2" | 0.8" | 💧 Light watering |
| Jul | 3" | 10.4" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 11.5" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 8.1" | 0" | ✅ Rainfall sufficient |
| Oct | 3" | 5.7" | 0" | ✅ Rainfall sufficient |
| Nov | 3" | 3" | 0" | ✅ Rainfall sufficient |
| Dec | — | 3.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in King 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 — King County, TX
Spinach Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 24 | Feb 24 – Mar 10 |
| Transplant Outdoors | March 31 | Mar 31 – Apr 14 |
| Direct Sow | March 17 | Mar 17 – Apr 7 |
| Harvest | May 5 | May 5 – Jul 7 |
| Fall Sowing | August 29 | Aug 29 – Sep 12 |
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 |
| 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_alkaline
🗺️ USDA Zone
Zone 7b
📆 Growing Season
221 days in King County
Growing Tips for Spinach in King County
Direct sow Spinach outdoors after March 31 in King County when soil has warmed and frost danger has passed.
Sandy soil in King County dries quickly — mulch Spinach with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
Summer highs in King County reach 99°F — grow Spinach as a spring or fall crop. Use shade cloth if planting in summer.
Your generous 221.0-day season in King 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 King 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 King County, TX?
King County is in Zone 7b with an average last frost of March 31. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.
What planting zone is King County, TX?
King County, Texas is in USDA Hardiness Zone 7b. The average last spring frost is March 31 and first fall frost is November 7.
Plan Your Garden with Confidence
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