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When to Plant Watermelon in Teton County, WY

Teton County, Wyoming Zone 4b May

May to-do list for Teton County, Wyoming

Your Teton County, Wyoming garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost June 16
Avg. first frost September 6
Soil temp (4") 34°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
Looking ahead to June
  • Direct-sowing: watermelon

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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.

Teton County, Wyoming is in USDA Zone 4b. The average last spring frost is June 16 and the first fall frost is September 6, giving you a growing season of approximately 82 days.

At an elevation of 6,591 feet, Teton County receives approximately 19.3 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Watermelon to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Watermelon successfully. Mulch heavily to conserve soil moisture.

Teton County, WY (Zone 4b) Very short season
82 days
Last Spring Frost June 16
82 growing days
First Fall Frost September 6
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Teton County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 18 Transplant: Jun 20 🍅 Harvest: Aug 29 – Oct 17
Recommended (50%) ✗ May not fit
Start indoors: May 5 Transplant: Jul 7 🍅 Harvest: Sep 15 – Nov 3
Safe Start (90%) ✗ May not fit
Start indoors: May 17 Transplant: Jul 19 🍅 Harvest: Sep 27 – Nov 15

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 Teton County

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

Soil pH

Your soil pH (6.8–7.6) overlaps with Watermelon's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help 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 Teton County's 82-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 448 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 1.6" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 2.2" 0" ❄️ Dormant
Jun 6.5" 1.3" 5.2" 🚿 Regular watering
Jul 6.5" 1.8" 4.7" 🚿 Regular watering
Aug 6.5" 1.8" 4.7" 🚿 Regular watering
Sep 6.5" 1.8" 4.7" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Teton 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 ~1,105 GDD — county provides 1,066 GDD Tight fit

Watermelon Planting Timeline — Teton County, WY

Watermelon Planting Calendar

Activity When Date Range
Start Indoors May 5 May 5 – May 19
Transplant Outdoors July 7 Jul 7 – Jul 21
Direct Sow June 30 Jun 30 – Jul 21
Harvest September 15 Sep 15 – Nov 3

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

82 days in Teton County

Growing Tips for Watermelon in Teton County

Direct sow Watermelon outdoors after June 16 in Teton County when soil has warmed and frost danger has passed.

Your 82.0-day growing season in Teton County is tight for Watermelon (70.0-100.0 days to maturity). Start indoors and choose early-maturing varieties.

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.

Teton County receives only 19" of rain annually. Watermelon needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Teton County

Compact, early melons for shorter seasons

Sugar Baby (75d) Blacktail Mountain (70d) Golden Midget (70d)

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 Teton County, WY?

Teton County is in Zone 4b with an average last frost of June 16. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Teton County, WY?

Teton County, Wyoming is in USDA Hardiness Zone 4b. The average last spring frost is June 16 and first fall frost is September 6.

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Your Teton County Garden Planner — Free

A 24-page printable planner built for Teton County (Zone 4b). 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 Teton County, WY. 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.