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When to Plant Corn in Solano 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.

Solano County, California is in USDA Zone 9a. The average last spring frost is February 9 and the first fall frost is December 3, giving you a growing season of approximately 297 days.

At an elevation of 376 feet, Solano County receives approximately 40.4 inches of rainfall annually with predominantly loam soil. Summer highs average 95ยฐF, so Corn may need afternoon shade and extra watering during peak heat.

Solano County, CA (Zone 9a) Year-round
297 days
Last Spring Frost February 9
297 growing days
First Fall Frost December 3

Solano County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (186 days to spare)
Transplant: Jan 25 🍅 Harvest: Mar 29 – May 24
Recommended (50%) ✓ Fits season (178 days to spare)
Transplant: Feb 9 🍅 Harvest: Apr 13 – Jun 8
Safe Start (90%) ✓ Fits season (162 days to spare)
Transplant: Mar 13 🍅 Harvest: May 15 – Jul 10

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 Solano County

How your county's soil matches Corn's growing requirements.

Soil pH

Your soil pH (6.8โ€“7.3) is more alkaline than Corn prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Solano County is excellent for Corn โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Corn.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Corn.

How to Plant Corn

1"
Planting Depth
12"
Between Plants
36"
Between Rows

Succession Planting Corn

5
successive plantings in your 297-day season

Sow every 6.9 weeks. Last sowing by Aug 25 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.7″/week
Watering frequency 2-3 times/week
Season total 4,394 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” 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 โ€” 8.9" 0" โ„๏ธ Dormant
Feb 6.5" 8.4" 0" โœ… Rainfall sufficient
Mar 6.5" 6.6" 0" โœ… Rainfall sufficient
Apr 6.5" 2.7" 3.8" ๐Ÿšฟ Regular watering
May 6.5" 1" 5.5" ๐Ÿšฟ Regular watering
Jun 6.5" 0.2" 6.3" ๐Ÿšฟ Regular watering
Jul 6.5" 0" 6.5" ๐Ÿšฟ Regular watering
Aug 6.5" 0" 6.5" ๐Ÿšฟ Regular watering
Sep 6.5" 0.4" 6.1" ๐Ÿšฟ Regular watering
Oct 6.5" 1.9" 4.6" ๐Ÿšฟ Regular watering
Nov 6.5" 3.3" 3.2" ๐Ÿ’ง Light watering
Dec 6.5" 7.1" 0" โœ… Rainfall sufficient

Water needs are for active growing months only (Febโ€“Dec in Solano County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 needs ~1,700 GDD — county provides 6,332 GDD Excellent fit

Corn Planting Timeline โ€” Solano County, CA

Corn Planting Calendar

Activity When Date Range
Direct Sow February 16 Feb 16 โ€“ Mar 9
Harvest April 20 Apr 20 โ€“ Jun 15

Plant 1" deep ยท 12" apart ยท Rows 36" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February Direct Sow
March Direct Sow
April Harvest
May Harvest
June Harvest
July โ€”
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.5"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

60โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 9a

๐Ÿ“† Growing Season

297 days in Solano County

Growing Tips for Corn in Solano County

Direct sow Corn outdoors after February 09 in Solano County when soil has warmed and frost danger has passed.

Common pests for 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 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 Solano County

Heat-tolerant varieties that silk well in high temps

Silver Queen (92d) Incredible (85d)

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Celery

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Corn in Solano County, CA?

Solano County is in Zone 9a with an average last frost of February 9. Plan your Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Solano County, CA?

Solano County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 9 and first fall frost is December 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Solano County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Solano County, CA. Local conditions may vary. Last updated: April 2026.