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Watermelon Growing Guide
Growing Guide

Watermelon

Watermelon is the quintessential Summertime treat in most areas of the world. Because of their popularity in home gardens, we get a lot of questions from both beginner and long-time gardeners when Spring garden planning begins. So let’s address the questions we get the most when deciding to grow your watermelons at home.

Quick Overview

Category Details
Planting Time Late spring after frost
Soil Temperature 70–95°F (best growth at 75–85°F)
Sunlight Requirements Full Sun (8+ hours)
Watering Requirements 1–2" per week
Spacing (In-Ground) Rows: 36–48″; Plants: 18–36″
Spacing (Raised Bed) Plants: 24–36″
Fertilizer Guidelines Moderate feeder – compost + balanced fertilizer

Growing Guide Details

Plant Classifications

Watermelons come in several main types based on fruit size and seed type. Standard seeded watermelons are known for their rich flavor and reliable production. Seedless watermelons are popular for fresh eating but require a seeded variety nearby for pollination. Icebox watermelons produce smaller fruits that mature faster and are perfect for small gardens or limited space.

What Variety to Choose?

💡

• Sugar Baby: Compact icebox watermelon producing small, sweet fruits—perfect for small gardens.

• Crimson Sweet: Classic large watermelon with bright red flesh and dependable yields.

• Charleston Gray: Large oblong melon with excellent disease resistance and sweet flavor.

• Jubilee: Long melon with crisp, sweet flesh and excellent productivity in warm climates.

When to Plant

Indoor Start:
Start watermelon seeds indoors 3–4 weeks before your last expected frost date if you want an earlier harvest.

Outdoor Planting:
Direct sow or transplant watermelons only after all danger of frost has passed and soil temperatures reach at least 70°F. Watermelons grow best in warm soil and will struggle in cool conditions.

Light & Space Requirements

Sunlight:
Watermelons require full sun for maximum fruit production. Aim for at least 8 hours of direct sunlight daily.

In-Ground Spacing:
Row spacing: 6–8 feet
Plant spacing: 3–4 feet

Watermelon vines spread aggressively and need plenty of room to grow.

Raised Beds:
Space plants 2–3 feet apart and allow vines to trail outside the bed if needed.

Pro Tip:
Plant on raised mounds or hills to improve drainage and warm soil faster in spring.

Sweetie Pie Watermelon

Soil & Fertility

Watermelons prefer loose, sandy soil rich in organic matter.

Soil Requirements:
pH: 6.0–6.8
Well-drained soil is essential
Add compost or aged manure before planting

Fertilizer Schedule:

Before Planting:
Mix 1½ cups of HOSS Complete Organic Fertilizer per 10 ft of row.

2 Weeks After Transplanting:
Using the Hoss Fertilizer Injector, Mix 1 cup ofHoss Premium 20-20-20 Fertilizer -AND -1-2 cups of Hoss Micro-Boost Micronutrient Supplement per 20 ft. of row.

Rotate Every 7 Days After Vines Beging to Run:
Mix 1 cup of Hoss Premium Calcium Nitrate -AND -1-2 cups of Hoss Micro-Boost Micronutrient Supplement per 20 ft. of row.

Pro Tip:
Flowering & Fruiting: Switch to a fertilizer higher in phosphorus and potassium to support fruit development.

Pest & Disease Control

Pest/Disease Control Method
Thrips

Garden Insect Spray, Take Down, Take Out
Aphids

Neem Oil, Horticulture Oil, Bug Buster-O, Take Down, Take Out
Cutworms

Monterey Bt, Diatomaceous Earth
Anthracnose

Complete Disease Control
Downy Mildew

Liquid Copper, Garden Phos
Gummy Stem Blight

Garden Phos
Damping Off (seed treatment)

Garden Phos

Irrigation & Watering Schedule

Watermelons require consistent moisture for proper fruit development.

Provide 1–2 inches of water per week, especially during flowering and fruit growth. Reduce watering slightly as melons near maturity to improve sweetness.

Drip irrigation or soaker hoses are ideal to deliver water directly to the roots while keeping foliage dry.

Mulching helps retain soil moisture and suppress weeds.

Crimson Sweet Watermelon

Crimson Sweet Watermelon

Harvesting & Storage

Harvest:
Watermelons are ready to harvest when the tendril closest to the fruit turns brown and dry. The underside of the melon (the ground spot) should also turn from white to creamy yellow.

Cut melons from the vine with pruning shears rather than pulling to avoid damaging the plant.

Storage:
Whole watermelons can be stored at room temperature for about a week or refrigerated for up to two weeks.

Preservation Tip:
Cut watermelon should be stored in an airtight container in the refrigerator and used within 3–4 days.

Sustainability & Garden Tips

• Rotate crops yearly to reduce soilborne diseases
• Use mulch to conserve moisture and control weeds
• Encourage pollinators for better fruit set
• Plant cover crops after harvest to restore soil nutrients

FAQs

How long does it take to grow a watermelon?

Most varieties take 70–100 days from planting to harvest.

Why are my watermelon vines growing but not producing fruit?

Poor pollination is often the cause. Encourage bees and other pollinators to visit your garden.

Can I grow watermelon in containers?

Yes, but choose smaller icebox varieties and use large containers with room for vines to spread.

Do watermelons need pollinators?

Yes. Bees are essential for proper pollination and fruit development.

Why are my watermelons not sweet?

Lack of sunlight, excessive watering near harvest, or harvesting too early can reduce sweetness.

Published on June 07, 2023
Updated on April 06, 2026