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When to Plant Cauliflower in Jefferson County, FL

Jefferson County, Florida Zone 9a May

May in Jefferson County, Florida — your action list

Welcome to May in Zone 9a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 9
Avg. first frost November 21
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Harvest cauliflower as they ripen

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Looking ahead to June
  • First harvests: cauliflower

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Cauliflower is a cool-season brassica that produces dense white, purple, or green heads called curds. It is more finicky than broccoli but rewards with a mild, nutty flavor.

Jefferson County, Florida is in USDA Zone 9a. The average last spring frost is March 9 and the first fall frost is November 21, giving you a growing season of approximately 257 days.

At an elevation of 105 feet, Jefferson County receives approximately 56 inches of rainfall annually with predominantly sand soil. Summer highs average 95°F, so Cauliflower may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Cauliflower will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Cauliflower root diseases.

Jefferson County, FL (Zone 9a) Long season
257 days
Last Spring Frost March 9
257 growing days
First Fall Frost November 21
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Jefferson County Soil Profile

Soil Type

Sand

Soil pH

5.2-5.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (133 days to spare)
Start indoors: Feb 4 Transplant: Mar 4 🍅 Harvest: Apr 29 – Jul 1
Recommended (50%) ✓ Fits season (138 days to spare)
Start indoors: Feb 9 Transplant: Mar 9 🍅 Harvest: May 4 – Jul 6
Safe Start (90%) ✓ Fits season (141 days to spare)
Start indoors: Feb 27 Transplant: Mar 27 🍅 Harvest: May 22 – Jul 24

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 Jefferson County

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

Soil pH

Your soil pH (5.2–5.9) is more acidic than Cauliflower prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Jefferson County warms quickly in spring but drains fast. Cauliflower will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Cauliflower is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is low (1.3%). Add 2-3 inches of compost before planting Cauliflower.

How to Plant Cauliflower

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

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Cauliflower

5
successive plantings in your 257-day season

Sow every 6.3 weeks. Last sowing by Aug 13 to harvest before frost.

For a dedicated fall crop, sow by Sep 26.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 880 gal / 100 sq ft

Monthly Watering Guide for Cauliflower

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

Month Cauliflower Needs Rainfall You Supplement Action
Jan 3" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 4.3" 3.2" 1.1" 💧 Light watering
Apr 4.3" 2.4" 1.9" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 7.8" 0" ✅ Rainfall sufficient
Jul 4.3" 8.9" 0" ✅ Rainfall sufficient
Aug 4.3" 7.4" 0" ✅ Rainfall sufficient
Sep 4.3" 6.4" 0" ✅ Rainfall sufficient
Oct 4.3" 5" 0" ✅ Rainfall sufficient
Nov 4.3" 2.5" 1.8" 💧 Light watering
Dec 2.7" 0" ❄️ Dormant

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

Cauliflower 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.

Cauliflower needs ~1,647 GDD — county provides 5,461 GDD Excellent fit

Cauliflower Planting Timeline — Jefferson County, FL

Cauliflower Planting Calendar

Activity When Date Range
Start Indoors February 9 Feb 9 – Feb 23
Transplant Outdoors March 9 Mar 9 – Mar 23
Direct Sow February 16 Feb 16 – Mar 9
Harvest May 4 May 4 – Jul 6
Fall Sowing September 26 Sep 26 – Oct 10

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

55–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

257 days in Jefferson County

Growing Tips for Cauliflower in Jefferson County

Direct sow Cauliflower outdoors after March 09 in Jefferson County when soil has warmed and frost danger has passed.

Sandy soil in Jefferson County dries quickly — mulch Cauliflower with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Summer highs in Jefferson County reach 95°F — grow Cauliflower as a spring or fall crop. Use shade cloth if planting in summer.

Common pests for Cauliflower 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 weeks before transplanting. Blanch white varieties by tying outer leaves over the head. Provide consistent moisture and avoid temperature extremes.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cauliflower in Jefferson County, FL?

Jefferson County is in Zone 9a with an average last frost of March 9. Plan your Cauliflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, FL?

Jefferson County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is March 9 and first fall frost is November 21.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 9a). 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 Jefferson County, FL. 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.