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When to Plant Soybeans in Duval County, FL

Duval County, Florida Zone 9b May

Your May gardening checklist

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 February 24
Avg. first frost November 29
Soil temp (4") 76°F
Watering Moderate
Pest pressure High
Daylight 13.5 hrs
  1. It's harvest week for soybeans

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Looking ahead to June
  • First harvests: soybeans

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Soybeans (edamame) are a high-protein legume that fixes nitrogen in the soil. Fresh green soybeans harvested at the edamame stage are a nutritious snack.

Duval County, Florida is in USDA Zone 9b. The average last spring frost is February 24 and the first fall frost is November 29, giving you a growing season of approximately 278 days.

At an elevation of 337 feet, Duval County receives approximately 56.9 inches of rainfall annually with predominantly sand soil. Summer highs average 102°F, so Soybeans may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Soybeans will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Soybeans root diseases.

Duval County, FL (Zone 9b) Year-round
278 days
Last Spring Frost February 24
278 growing days
First Fall Frost November 29

Duval County Soil Profile

Soil Type

Sand

Soil pH

5-5.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (143 days to spare)
Transplant: Feb 11 🍅 Harvest: May 6 – Jul 1
Recommended (50%) ✓ Fits season (138 days to spare)
Transplant: Feb 24 🍅 Harvest: May 19 – Jul 14
Safe Start (90%) ✓ Fits season (134 days to spare)
Transplant: Mar 21 🍅 Harvest: Jun 13 – Aug 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 Duval County

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

Soil pH

Your soil pH (5.0–5.8) is more acidic than Soybeans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is low (1.4%). Add 2-3 inches of compost before planting Soybeans.

How to Plant Soybeans

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

Succession Planting Soybeans

4
successive plantings in your 278-day season

Sow every 9.1 weeks. Last sowing by Aug 01 to harvest before frost.

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 356 gal / 100 sq ft

Monthly Watering Guide for Soybeans

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

Month Soybeans Needs Rainfall You Supplement Action
Jan 2.6" 0" ❄️ Dormant
Feb 4.3" 2.8" 1.5" 💧 Light watering
Mar 4.3" 3.6" 0.7" 💧 Light watering
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 8.7" 0" ✅ Rainfall sufficient
Jul 4.3" 7.8" 0" ✅ Rainfall sufficient
Aug 4.3" 8.9" 0" ✅ Rainfall sufficient
Sep 4.3" 6.3" 0" ✅ Rainfall sufficient
Oct 4.3" 4.7" 0" ✅ Rainfall sufficient
Nov 4.3" 2.6" 1.7" 💧 Light watering
Dec 2.4" 0" ❄️ Dormant

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

Soybeans 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.

Soybeans needs ~2,650 GDD — county provides 7,393 GDD Excellent fit

Soybeans Planting Timeline — Duval County, FL

Soybeans Planting Calendar

Activity When Date Range
Direct Sow March 3 Mar 3 – Mar 24
Harvest May 26 May 26 – Jul 21

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

Month-by-Month Timeline

MonthActivities
January
February
March Direct Sow
April
May Harvest
June Harvest
July Harvest
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

278 days in Duval County

Growing Tips for Soybeans in Duval County

Direct sow Soybeans outdoors after February 24 in Duval County when soil has warmed and frost danger has passed.

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

With summer highs reaching 102°F in Duval County, provide afternoon shade for Soybeans and water deeply in the morning.

Common pests for Soybeans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after soil warms to 60F. Plant in blocks rather than rows for better pollination. Harvest for edamame when pods are plump and bright green.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Soybeans in Duval County, FL?

Duval County is in Zone 9b with an average last frost of February 24. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Duval County, FL?

Duval County, Florida is in USDA Hardiness Zone 9b. The average last spring frost is February 24 and first fall frost is November 29.

🌱

Your Duval County Garden Planner — Free

A 24-page printable planner built for Duval 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 Duval 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.