When to plant Spinach in Harmony, CA
Plant Spinach in Harmony, when soil hits 50°F — usually March 2. Continue planting through March 23 for the spring crop. A second sowing from September 14 to September 28 extends the harvest into fall.
When to Plant Spinach in Harmony, CA
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.
Harmony, California is in USDA Zone 10a. The average last spring frost is March 23 and the first fall frost is November 9, giving you a growing season of approximately 231 days.
At an elevation of 2,412 feet, San Luis Obispo County receives approximately 18.4 inches of rainfall annually with predominantly loam soil. Summer highs average 98°F, so Spinach may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Spinach successfully. Mulch heavily to conserve soil moisture.
Harmony Soil Profile
Soil Type
Loam
Soil pH
6.6-7.8
Drainage
Well Drained
Monthly Watering Guide for Spinach
Spinach needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Spinach Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 4" | 0" | ❄️ Dormant |
| Feb | — | 3.9" | 0" | ❄️ Dormant |
| Mar | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Apr | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| May | 4.3" | 0.5" | 3.8" | 🚿 Regular watering |
| Jun | 4.3" | 0.1" | 4.2" | 🚿 Regular watering |
| Jul | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Aug | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Sep | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Oct | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Nov | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Dec | — | 2.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in San Luis Obispo County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Spinach Planting Timeline — Harmony, CA
Spinach Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 23 | Feb 23 – Mar 9 |
| Transplant Outdoors | March 23 | Mar 23 – Apr 6 |
| Direct Sow | March 2 | Mar 2 – Mar 23 |
| Harvest | April 27 | Apr 27 – Jun 29 |
| Fall Sowing | September 14 | Sep 14 – Sep 28 |
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 Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
35–50 days
🧪 Soil pH
Needs 6.5–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 10a
📆 Growing Season
231 days in San Luis Obispo County
Growing Tips for Harmony
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
When should I plant Spinach in Harmony, CA?
In Harmony, CA, plant Spinach after the last frost (around March 23) and before the first frost (around November 9). Best results when soil holds above 50°F.
What growing zone is Harmony, CA for Spinach?
Harmony sits in USDA Zone 10a. Spinach grows reliably in zones 2a through 10b, so it's a good fit here.
Can Spinach grow in Harmony's climate?
Yes — Spinach grows well in Harmony's temperate climate. Harmony averages a 231-day frost-free season, with last frost around March 23 and first frost around November 9.
Your San Luis Obispo County Garden Planner — Free
A 22-page printable planner built for San Luis Obispo County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.