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When to Plant Sweet Corn in Jack County, TX

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.

Jack County, Texas is in USDA Zone 7b. The average last spring frost is March 26 and the first fall frost is November 9, giving you a growing season of approximately 228 days.

At an elevation of 2,081 feet, Jack County receives approximately 66.9 inches of rainfall annually with predominantly clay soil. Summer highs average 89ยฐF, providing good warmth for Sweet Corn during the growing season. Clay soil retains moisture well for Sweet Corn, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Corn root diseases.

Jack County, TX (Zone 7b) Long season
228 days
Last Spring Frost March 26
228 growing days
First Fall Frost November 9

Jack County Soil Profile

Soil Type

Clay

Soil pH

7.3-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (123 days to spare)
Transplant: Mar 19 🍅 Harvest: May 21 – Jul 2
Recommended (50%) ✓ Fits season (123 days to spare)
Transplant: Mar 26 🍅 Harvest: May 28 – Jul 9
Safe Start (90%) ✓ Fits season (117 days to spare)
Transplant: Apr 16 🍅 Harvest: Jun 18 – Jul 30

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 Jack County

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

Soil pH

Your soil pH (7.3โ€“7.6) is more alkaline than Sweet Corn prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (42% clay) in Jack County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Drainage

Drainage is adequate for Sweet Corn.

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Sweet Corn.

How to Plant Sweet Corn

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

Succession Planting Sweet Corn

4
successive plantings in your 228-day season

Sow every 6.9 weeks. Last sowing by Aug 11 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 โ€” 2" 0" โ„๏ธ Dormant
Feb โ€” 2.3" 0" โ„๏ธ Dormant
Mar 6.5" 3.7" 2.8" ๐Ÿ’ง Light watering
Apr 6.5" 8" 0" โœ… Rainfall sufficient
May 6.5" 9.7" 0" โœ… Rainfall sufficient
Jun 6.5" 9.6" 0" โœ… Rainfall sufficient
Jul 6.5" 8.5" 0" โœ… Rainfall sufficient
Aug 6.5" 7.6" 0" โœ… Rainfall sufficient
Sep 6.5" 6.7" 0" โœ… Rainfall sufficient
Oct 6.5" 4.3" 2.2" ๐Ÿ’ง Light watering
Nov 6.5" 2.6" 3.9" ๐Ÿšฟ Regular watering
Dec โ€” 1.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Jack County). Supplement amounts are based on average rainfall โ€” 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" 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.

Sweet Corn needs ~1,256 GDD — county provides 3,819 GDD Excellent fit

Sweet Corn Planting Timeline โ€” Jack County, TX

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow April 2 Apr 2 โ€“ Apr 23
Harvest June 4 Jun 4 โ€“ Jul 16

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Direct Sow
May โ€”
June Harvest
July Harvest
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 Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 7b

๐Ÿ“† Growing Season

228 days in Jack County

Growing Tips for Sweet Corn in Jack County

Direct sow Sweet Corn outdoors after March 26 in Jack County when soil has warmed and frost danger has passed.

With Jack County's clay soil (42% clay), work in 3-4 inches of compost before planting Sweet Corn. Avoid tilling when soil is wet to prevent compaction.

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

  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Corn in Jack County, TX?

Jack County is in Zone 7b with an average last frost of March 26. Plan your Sweet Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jack County, TX?

Jack County, Texas is in USDA Hardiness Zone 7b. The average last spring frost is March 26 and first fall frost is November 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jack County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.

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