When to Plant Corn in Alameda 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.
Alameda County, California is in USDA Zone 9b. The average last spring frost is January 18 and the first fall frost is December 12, giving you a growing season of approximately 328 days.
At an elevation of 379 feet, Alameda County receives approximately 16.4 inches of rainfall annually with predominantly loam soil. Summer highs average 97°F, so Corn may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Corn successfully. Mulch heavily to conserve soil moisture.
Alameda County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.7
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 Alameda County
How your county's soil matches Corn's growing requirements.
Soil pH
Your soil pH (6.3–7.7) overlaps with Corn's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Alameda County is excellent for Corn — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Corn.
How to Plant Corn
Succession Planting Corn
Sow every 6.9 weeks. Last sowing by Sep 03 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Corn
Corn needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.
| Month | Corn Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | 6.5" | 3" | 3.5" | 🚿 Regular watering |
| Feb | 6.5" | 3.6" | 2.9" | 💧 Light watering |
| Mar | 6.5" | 2.6" | 3.9" | 🚿 Regular watering |
| Apr | 6.5" | 1.2" | 5.3" | 🚿 Regular watering |
| May | 6.5" | 0.4" | 6.1" | 🚿 Regular watering |
| Jun | 6.5" | 0.1" | 6.4" | 🚿 Regular watering |
| Jul | 6.5" | 0" | 6.5" | 🚿 Regular watering |
| Aug | 6.5" | 0" | 6.5" | 🚿 Regular watering |
| Sep | 6.5" | 0.2" | 6.3" | 🚿 Regular watering |
| Oct | 6.5" | 0.6" | 5.9" | 🚿 Regular watering |
| Nov | 6.5" | 1.5" | 5" | 🚿 Regular watering |
| Dec | 6.5" | 3.1" | 3.4" | 🚿 Regular watering |
Water needs are for active growing months only (Jan–Dec in Alameda County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Corn 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.
Corn Planting Timeline — Alameda County, CA
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | January 25 | Jan 25 – Feb 15 |
| Harvest | March 29 | Mar 29 – May 24 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Direct Sow |
| February | Direct Sow |
| March | Harvest |
| April | Harvest |
| May | Harvest |
| June | — |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.5"/week · 2-3 times/week
📅 Days to Maturity
60–100 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 9b
📆 Growing Season
328 days in Alameda County
Growing Tips for Corn in Alameda County
Direct sow Corn outdoors after January 18 in Alameda County when soil has warmed and frost danger has passed.
With summer highs reaching 97°F in Alameda County, provide afternoon shade for Corn and water deeply in the morning.
Common pests for Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.
Alameda County receives only 16" of rain annually. Corn needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
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.
Recommended Corn Varieties for Alameda County
Heat-tolerant varieties that silk well in high temps
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 Alameda County, CA?
Alameda County is in Zone 9b with an average last frost of January 18. Plan your Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Alameda County, CA?
Alameda County, California is in USDA Hardiness Zone 9b. The average last spring frost is January 18 and first fall frost is December 12.
Plan Your Garden with Confidence
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