When to Plant Sweet Corn in Ontario County, NY
Your May planting checklist for Ontario County, New York
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Ontario County, New York.
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Put sweet corn seeds straight in the ground
Your soil is 60°F — warm enough for these to germinate without babying.
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.
Ontario County, New York is in USDA Zone 6b. The average last spring frost is April 29 and the first fall frost is October 20, giving you a growing season of approximately 174 days.
At an elevation of 33 feet, Ontario County receives approximately 50 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Sweet Corn to ensure they mature before fall.
Ontario County Soil Profile
Soil Type
Silt Loam
Soil pH
4.9-6.6
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 Ontario County
How your county's soil matches Sweet Corn's growing requirements.
Soil pH
Your soil pH (4.9–6.6) is more acidic than Sweet Corn prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Ontario County is excellent for Sweet Corn — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Sweet Corn.
How to Plant Sweet Corn
Succession Planting Sweet Corn
Sow every 6.9 weeks. Last sowing by Jul 22 to harvest before frost.
Plant Water Budget
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 | — | 3.3" | 0" | ❄️ Dormant |
| Feb | — | 3.6" | 0" | ❄️ Dormant |
| Mar | — | 3.9" | 0" | ❄️ Dormant |
| Apr | 6.5" | 3.8" | 2.7" | 💧 Light watering |
| May | 6.5" | 4.8" | 1.7" | 💧 Light watering |
| Jun | 6.5" | 5" | 1.5" | 💧 Light watering |
| Jul | 6.5" | 4.7" | 1.8" | 💧 Light watering |
| Aug | 6.5" | 4.4" | 2.1" | 💧 Light watering |
| Sep | 6.5" | 4.4" | 2.1" | 💧 Light watering |
| Oct | 6.5" | 4.1" | 2.4" | 💧 Light watering |
| Nov | — | 4.1" | 0" | ❄️ Dormant |
| Dec | — | 4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Ontario 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 — Ontario County, NY
Sweet Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 6 | May 6 – May 27 |
| Harvest | July 8 | Jul 8 – Aug 19 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.5"/week · Only during dry spells
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6b
📆 Growing Season
174 days in Ontario County
Growing Tips for Sweet Corn in Ontario County
Direct sow Sweet Corn outdoors after April 29 in Ontario County when soil has warmed and frost danger has passed.
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.
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 Ontario County, NY?
Ontario County is in Zone 6b with an average last frost of April 29. Plan your Sweet Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Ontario County, NY?
Ontario County, New York is in USDA Hardiness Zone 6b. The average last spring frost is April 29 and first fall frost is October 20.
Your Ontario County Garden Planner — Free
A 24-page printable planner built for Ontario County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.