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When to Plant Collard Greens in St. Johns County, FL

St. Johns County, Florida Zone 9b April

Your April planting checklist for St. Johns County, Florida

April rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in St. Johns County, Florida.

Avg. last frost February 9
Avg. first frost December 2
Soil temp (4") 70°F
Watering Moderate
Pest pressure High
Daylight 12.7 hrs
  1. Collect collard greens at their peak

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

To set up a strong May, finish these tasks
  • First harvests: collard greens

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Collard greens are a heat-tolerant member of the cabbage family with large, sturdy leaves. They are a Southern staple and one of the most nutritious leafy greens.

St. Johns County, Florida is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 2, giving you a growing season of approximately 296 days.

At an elevation of 57 feet, St. Johns County receives approximately 51.1 inches of rainfall annually with predominantly sand soil. Summer highs average 99°F, so Collard Greens may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Collard Greens will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Collard Greens root diseases.

St. Johns County, FL (Zone 9b) Year-round
296 days
Last Spring Frost February 9
296 growing days
First Fall Frost December 2

St. Johns County Soil Profile

Soil Type

Sand

Soil pH

4.9-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (188 days to spare)
Start indoors: Dec 28 Transplant: Jan 25 🍅 Harvest: Mar 22 – May 24
Recommended (50%) ✓ Fits season (177 days to spare)
Start indoors: Jan 12 Transplant: Feb 9 🍅 Harvest: Apr 6 – Jun 8
Safe Start (90%) ✓ Fits season (168 days to spare)
Start indoors: Feb 11 Transplant: Mar 11 🍅 Harvest: May 6 – Jul 8

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 St. Johns County

How your county's soil matches Collard Greens's growing requirements.

Soil pH

Your soil pH (4.9–6.1) is more acidic than Collard Greens prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in St. Johns County warms quickly in spring but drains fast. Collard Greens will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.5%). Add 2-3 inches of compost before planting Collard Greens.

How to Plant Collard Greens

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 Collard Greens

6
successive plantings in your 296-day season

Sow every 6.3 weeks. Last sowing by Sep 18 to harvest before frost.

For a dedicated fall crop, sow by Oct 07.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.7″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 245 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Collard Greens

Collard Greens needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Collard Greens Needs Rainfall You Supplement Action
Jan 2.4" 0" ❄️ Dormant
Feb 3.5" 2.4" 1.1" 💧 Light watering
Mar 3.5" 2.8" 0.7" 💧 Light watering
Apr 3.5" 2.8" 0.7" 💧 Light watering
May 3.5" 3.5" 0" ✅ Rainfall sufficient
Jun 3.5" 7" 0" ✅ Rainfall sufficient
Jul 3.5" 7.1" 0" ✅ Rainfall sufficient
Aug 3.5" 7.6" 0" ✅ Rainfall sufficient
Sep 3.5" 6.9" 0" ✅ Rainfall sufficient
Oct 3.5" 4.3" 0" ✅ Rainfall sufficient
Nov 3.5" 2.1" 1.4" 💧 Light watering
Dec 3.5" 2.3" 1.2" 💧 Light watering

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

Collard Greens 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.

Collard Greens needs ~1,576 GDD — county provides 7,202 GDD Excellent fit

Collard Greens Planting Timeline — St. Johns County, FL

Collard Greens Planting Calendar

Activity When Date Range
Start Indoors January 12 Jan 12 – Jan 26
Transplant Outdoors February 9 Feb 9 – Feb 23
Direct Sow January 19 Jan 19 – Feb 9
Harvest April 6 Apr 6 – Jun 8
Fall Sowing October 7 Oct 7 – Oct 21

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Only during dry spells

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

296 days in St. Johns County

Growing Tips for Collard Greens in St. Johns County

Direct sow Collard Greens outdoors after February 09 in St. Johns County when soil has warmed and frost danger has passed.

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

With summer highs reaching 99°F in St. Johns County, provide afternoon shade for Collard Greens and water deeply in the morning.

Common pests for Collard Greens 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 or direct sow 4-6 weeks before last frost. Harvest lower leaves first, leaving the growing tip intact. Flavor improves after exposure to frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Collard Greens in St. Johns County, FL?

St. Johns County is in Zone 9b with an average last frost of February 9. Plan your Collard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Johns County, FL?

St. Johns County, Florida is in USDA Hardiness Zone 9b. The average last spring frost is February 9 and first fall frost is December 2.

🌱

Your St. Johns County Garden Planner — Free

A 24-page printable planner built for St. Johns County (Zone 9b). 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 St. Johns County, FL. Local conditions may vary. Last updated: April 2026.

Sources & credits

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