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When to plant Watermelon in Monroe County, FL

Watermelon planted in Monroe County between January 22 and February 12 matures in 100 days — well before the December 31 first frost.

When to Plant Watermelon in Monroe County, FL

Watermelon
Monroe County, Florida Zone 11b June

Your June gardening checklist

A quick June briefing for Monroe County, Florida gardeners — what's urgent, what's next, and what can wait.

Avg. last frost January 22
Soil temp (4") 88°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Survive, don't thrive

    June-August is endurance gardening. Keep okra, peppers, sweet potatoes, and southern peas alive. Harvest everything daily before the heat damages produce on the vine.

  2. Start fall tomato seeds indoors

    Yes, indoors — under lights or in AC. They'll be ready to transplant in August when temperatures briefly moderate.

  3. Add compost to empty beds

    Empty beds get a thick layer of compost + mulch to suppress weeds and feed the soil for fall planting.

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Watermelon is a sprawling vine crop that produces sweet, juicy fruits in hot weather. Varieties range from personal-sized icebox types to 50-pound giants.

Monroe County, Florida is in USDA Zone 11b. The average last spring frost is January 22 and the first fall frost is April 15, giving you a growing season of approximately 83 days.

At an elevation of 169 feet, Monroe County receives approximately 55.6 inches of rainfall annually with predominantly sand soil. Summer highs average 93°F, providing good warmth for Watermelon during the growing season. Sandy soil warms quickly in spring — great for early planting — but Watermelon will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watermelon root diseases.

Monroe County, FL (Zone 11b) Year-round
365 days
Last Spring Frost No frost
365 growing days
First Fall Frost No frost

Monroe County Soil Profile

Soil Type

Sand

Soil pH

4.8-5.7

Drainage

Well Drained

Soil Compatibility in Monroe County

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

Soil pH

Your soil pH (4.8–5.7) is more acidic than Watermelon prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Watermelon.

Organic Matter

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

How to Plant Watermelon

1"
Planting Depth
30"
Between Plants
42"
Between Rows

How Much Watermelon to Grow

15-20 lbs
Average yield per plant
1
Plants per person
8.8 sq ft
Space per person

For a family of 4, plant approximately 4 watermelon plants in about 35 sq ft. In Monroe County's 365-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Watermelon Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 4,256 gal / 100 sq ft

Monthly Watering Guide for Watermelon

Watermelon needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Watermelon Needs Rainfall You Supplement Action
Jan 6.5" 2.3" 4.2" 🚿 Regular watering
Feb 6.5" 2.7" 3.8" 🚿 Regular watering
Mar 6.5" 3.8" 2.7" 💧 Light watering
Apr 6.5" 2.5" 4" 🚿 Regular watering
May 6.5" 3.2" 3.3" 🚿 Regular watering
Jun 6.5" 7.1" 0" ✅ Rainfall sufficient
Jul 6.5" 8.2" 0" ✅ Rainfall sufficient
Aug 6.5" 8.7" 0" ✅ Rainfall sufficient
Sep 6.5" 7.7" 0" ✅ Rainfall sufficient
Oct 6.5" 4.8" 1.7" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

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

Watermelon 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.

Watermelon needs ~1,679 GDD — county provides 7,208 GDD Excellent fit

Watermelon Planting Timeline — Monroe County, FL

Watermelon Planting Calendar

Activity When Date Range
Start Indoors December 25 Dec 25 – Jan 8
Transplant Outdoors January 29 Jan 29 – Feb 12
Direct Sow January 22 Jan 22 – Feb 12
Harvest April 9 Apr 9 – May 28

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 11b

📆 Growing Season

365 days in Monroe County

Growing Tips for Watermelon in Monroe County

Direct sow Watermelon outdoors after January 22 in Monroe County when soil has warmed and frost danger has passed.

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

Common pests for Watermelon in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 3-4 weeks early or direct sow after soil is warm. Plant on mounds with plenty of space. Check ripeness by looking for a yellow ground spot and dull thump when tapped.

Recommended Watermelon Varieties for Monroe County

Full-size melons that thrive with your long season

Crimson Sweet (85d) Charleston Gray (85d) Moon and Stars (95d)

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Watermelon in Monroe County, FL?

Monroe County is in Zone 11b with an average last frost of January 22. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monroe County, FL?

Monroe County, Florida is in USDA Hardiness Zone 11b. The average last spring frost is January 22 and first fall frost is .

When should I plant Watermelon in Monroe County, FL?

In Monroe County, FL, plant Watermelon after the last frost (around January 1) and before the first frost (around December 31). Best results when soil holds above 50°F.

What growing zone is Monroe County, FL for Watermelon?

Monroe County sits in USDA Zone 11b. Watermelon grows reliably in zones 4a through 11b, so it's a good fit here.

Can Watermelon grow in Monroe County's climate?

Yes — Watermelon grows well in Monroe County's temperate climate. Monroe County averages a 365-day frost-free season, with last frost around January 1 and first frost around December 31.

🌱

Your Monroe County Garden Planner — Free

A 22-page printable planner built for Monroe County (Zone 11b). 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 Monroe County, FL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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