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When to Plant Broccoli in DeKalb County, MO

Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.

DeKalb County, Missouri is in USDA Zone 5b. The average last spring frost is April 14 and the first fall frost is October 18, giving you a growing season of approximately 187 days.

At an elevation of 917 feet, DeKalb County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Broccoli during the growing season.

DeKalb County, MO (Zone 5b) Moderate season
187 days
Last Spring Frost April 14
187 growing days
First Fall Frost October 18

DeKalb County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (79 days to spare)
Start indoors: Mar 6 Transplant: Apr 10 🍅 Harvest: Jun 12 – Jul 24
Recommended (50%) ✓ Fits season (82 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jun 16 – Jul 28
Safe Start (90%) ✓ Fits season (79 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jul 2 – Aug 13

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 DeKalb County

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

Soil pH

Your soil pH (5.5โ€“7.1) overlaps with Broccoli's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Broccoli.

How to Plant Broccoli

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Broccoli

3
successive plantings in your 187-day season

Sow every 6.9 weeks. Last sowing by Jul 20 to harvest before frost.

For a dedicated fall crop, sow by Aug 09.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 206 gal / 100 sq ft
Broccoli needs ~1,144 GDD — county provides 2,851 GDD Excellent fit

Broccoli Planting Timeline โ€” DeKalb County, MO

Broccoli Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 โ€“ Mar 24
Transplant Outdoors April 14 Apr 14 โ€“ Apr 28
Direct Sow March 31 Mar 31 โ€“ Apr 21
Fall Sowing August 9 Aug 9 โ€“ Aug 23
Harvest June 16 Jun 16 โ€“ Jul 28

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May โ€”
June Harvest
July Harvest
August Fall Sowing
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

187 days in DeKalb County

Growing Tips for Broccoli in DeKalb County

Direct sow Broccoli outdoors after April 14 in DeKalb County when soil has warmed and frost danger has passed.

Common pests for Broccoli in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Level Up Your Garden

๐ŸŒพ Save Your Own Broccoli Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow plants to flower 2nd year; collect dry pods.
Storage Store airtight; viable 5 years at 35ยฐF, under 50% humidity.

Isolate 1/2 mile from other brassicas. Biennial โ€” must overwinter roots.

Frequently Asked Questions

When should I plant Broccoli in DeKalb County, MO?

DeKalb County is in Zone 5b with an average last frost of April 14. Plan your Broccoli planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is DeKalb County, MO?

DeKalb County, Missouri is in USDA Hardiness Zone 5b. The average last spring frost is April 14 and first fall frost is October 18.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help DeKalb County gardeners in Zone 5b 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 DeKalb County, MO. Local conditions may vary. Last updated: April 2026.