When to Plant Sweet Corn in Madera County, CA
What to do in May
Here's what deserves your attention in Madera County, California this month. Everything below is tailored to Zone 9a and timed around your local frost dates.
To set up a strong June, finish these tasks
- First harvests: sweet corn
Sweet corn is bred for high sugar content in its kernels, which convert to starch rapidly after harvest. Modern supersweet varieties hold their sweetness longer.
Madera County, California is in USDA Zone 9a. The average last spring frost is April 18 and the first fall frost is November 9, giving you a growing season of approximately 205 days.
At an elevation of 187 feet, Madera County receives approximately 14.5 inches of rainfall annually with predominantly loam soil. Summer highs average 104°F, so Sweet Corn may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Sweet Corn successfully. Mulch heavily to conserve soil moisture.
Madera County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.8
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 Madera County
How your county's soil matches Sweet Corn's growing requirements.
Soil pH
Your soil pH (6.2–7.8) overlaps with Sweet Corn's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Madera County is excellent for Sweet Corn — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Sweet Corn.
How to Plant Sweet Corn
Succession Planting Sweet Corn
Sow every 6.9 weeks. Last sowing by Aug 11 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Sweet Corn
Sweet 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 | Sweet Corn Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.6" | 0" | ❄️ Dormant |
| Feb | — | 2.9" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 6.5" | 1.3" | 5.2" | 🚿 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" | 0.1" | 6.4" | 🚿 Regular watering |
| Oct | 6.5" | 0.7" | 5.8" | 🚿 Regular watering |
| Nov | 6.5" | 1.4" | 5.1" | 🚿 Regular watering |
| Dec | — | 2.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Madera County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sweet 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.
Sweet Corn Planting Timeline — Madera County, CA
Sweet Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 25 | Apr 25 – May 16 |
| Harvest | June 27 | Jun 27 – Aug 8 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.5"/week · 2-3 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
205 days in Madera County
Growing Tips for Sweet Corn in Madera County
Direct sow Sweet Corn outdoors after April 18 in Madera County when soil has warmed and frost danger has passed.
With summer highs reaching 104°F in Madera County, provide afternoon shade for Sweet Corn and water deeply in the morning.
Common pests for Sweet Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.
Madera County receives only 14" of rain annually. Sweet 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 for wind pollination. Direct sow after soil is warm. Isolate supersweet varieties from other corn types to prevent cross-pollination.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Sweet Corn in Other Locations
Frequently Asked Questions
When should I plant Sweet Corn in Madera County, CA?
Madera County is in Zone 9a with an average last frost of April 18. Plan your Sweet Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Madera County, CA?
Madera County, California is in USDA Hardiness Zone 9a. The average last spring frost is April 18 and first fall frost is November 9.
Your Madera County Garden Planner — Free
A 24-page printable planner built for Madera County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.