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When to Plant Broccoli in Marshall County, KS

Marshall County, Kansas Zone 6a May

May in the garden — Marshall County, Kansas

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 22
Avg. first frost October 14
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.2 hrs
  1. Fire up the seed-starting tray: broccoli

    These need a head start before your last frost (April 22). Sow into cells now so you're ready to transplant in a few weeks.

June will be here before you know it — start on
  • First harvests: broccoli

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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.

Marshall County, Kansas is in USDA Zone 6a. The average last spring frost is April 22 and the first fall frost is October 14, giving you a growing season of approximately 175 days.

At an elevation of 840 feet, Marshall County receives approximately 22.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Broccoli to ensure they mature before fall.

Marshall County, KS (Zone 6a) Moderate season
175 days
Last Spring Frost April 22
175 growing days
First Fall Frost October 14
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Marshall County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Jun 18 – Jul 30
Recommended (50%) ✓ Fits season (70 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jun 24 – Aug 5
Safe Start (90%) ✓ Fits season (72 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Jul 6 – Aug 17

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 Marshall County

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

Soil pH

Your soil pH (6.6–7.8) is more alkaline than Broccoli prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Marshall County is excellent for Broccoli — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Broccoli.

Organic Matter

Organic matter is excellent (4.0%) — Broccoli will thrive.

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 175-day season

Sow every 6.9 weeks. Last sowing by Jul 16 to harvest before frost.

For a dedicated fall crop, sow by Aug 05.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,411 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Broccoli

Broccoli needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Broccoli Needs Rainfall You Supplement Action
Jan 0.6" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 4.3" 2.2" 2.1" 💧 Light watering
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 3.2" 1.1" 💧 Light watering
Aug 4.3" 2.4" 1.9" 💧 Light watering
Sep 4.3" 2.1" 2.2" 🚿 Regular watering
Oct 4.3" 1.7" 2.6" 🚿 Regular watering
Nov 0.7" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Marshall County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Broccoli 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.

Broccoli needs ~975 GDD — county provides 2,275 GDD Excellent fit

Broccoli Planting Timeline — Marshall County, KS

Broccoli Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 8 Apr 8 – Apr 29
Harvest June 24 Jun 24 – Aug 5
Fall Sowing August 5 Aug 5 – Aug 19

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

175 days in Marshall County

Growing Tips for Broccoli in Marshall County

Direct sow Broccoli outdoors after April 22 in Marshall 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.

Marshall County receives only 23" of rain annually. Broccoli needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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

Check more plant combinations with our Companion Planting Checker →

🌾 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 35°F, under 50% humidity.

Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.

Frequently Asked Questions

When should I plant Broccoli in Marshall County, KS?

Marshall County is in Zone 6a with an average last frost of April 22. Plan your Broccoli planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marshall County, KS?

Marshall County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 22 and first fall frost is October 14.

🌱

Your Marshall County Garden Planner — Free

A 24-page printable planner built for Marshall County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Marshall County, KS. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.