When to plant Corn in Marin County, CA
The best window to plant Corn in Marin County, is March 5–March 26, when soil warms to 50°F. Last frost typically hits February 26; first frost November 26.
When to Plant Corn in Marin County, CA
Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.
Marin County, California is in USDA Zone 9b. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.
At an elevation of 302 feet, Marin County receives approximately 36 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 81°F, so choose short-season varieties of Corn to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Corn will need more frequent watering and organic matter to retain nutrients.
Marin County Soil Profile
Soil Type
Sandy Loam
Soil pH
6-6.9
Drainage
Well Drained
How Much Corn to Grow
For a family of 4, plant approximately 60 corn plants in about 120 sq ft. In Marin County's 273-day season, you'll have plenty of time for a full harvest. Plan your garden layout →
Monthly Watering Guide for Corn
Corn needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Corn Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 7.2" | 0" | ❄️ Dormant |
| Feb | 4.3" | 6.5" | 0" | ✅ Rainfall sufficient |
| Mar | 4.3" | 6.2" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| May | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Jun | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Jul | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Aug | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Sep | 4.3" | 0.4" | 3.9" | 🚿 Regular watering |
| Oct | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Nov | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Dec | — | 6.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Marin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Corn Planting Timeline — Marin County, CA
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | March 5 | Mar 5 – Mar 26 |
| Harvest | May 7 | May 7 – Jul 2 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Direct Sow |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
60–100 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 9b
📆 Growing Season
273 days in Marin County
Growing Tips for Marin County
Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Corn in Other Locations
Frequently Asked Questions
When should I plant Corn in Marin County, CA?
Marin County is in Zone 9b with an average last frost of February 26. Plan your Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marin County, CA?
Marin County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 26 and first fall frost is November 26.
When should I plant Corn in Marin County, CA?
In Marin County, CA, plant Corn after the last frost (around February 26) and before the first frost (around November 26). Best results when soil holds above 50°F.
What growing zone is Marin County, CA for Corn?
Marin County sits in USDA Zone 9b. Corn grows reliably in zones 3a through 11b, so it's a good fit here.
Can Corn grow in Marin County's climate?
Yes — Corn grows well in Marin County's temperate climate. Marin County averages a 274-day frost-free season, with last frost around February 26 and first frost around November 26.
Your Marin County Garden Planner — Free
A 22-page printable planner built for Marin County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.