How to Grow Watermelon

Homegrown watermelon picked at the peak of sweetness tastes so much better than store-bought. Impress friends and family with your green thumb by adding this beloved fruit to your garden. Learn how to grow watermelon, and you’ll be enjoying juicy, homegrown watermelon all summer long!

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7 Tips for How to Grow Watermelon

Watermelon needs plenty of space and at least 80 days of warm temperatures to grow well. If you have both, learn how to grow watermelon with these tips.

1. Select the best variety of quality seeds for your climate and location

In warm climates, most varieties do well. Some favorites include Crimson Sweet and Moon and Stars.

In hot summer climates like the low desert of Arizona, choose short-season varieties or types adapted to the heat of the summer such as Desert King and Hopi Yellow.

In cooler climates, choose short-season varieties such as Golden Midget and Sugar Baby.

Smaller growing space? Choose shorter-vining varieties such as Bush Sugar Baby or Cal Sweet Bush. 

2. Choose and prepare a good location for planting watermelon

• Watermelon plants require a lot of space to grow and thrive, with some vines reaching up to 20 feet or more. Give them ample room. Planting at the edge of beds or growing watermelon vertically gives watermelon room to grow.
• Before planting, amend the area with compost and/or aged manure. Boost the soil further with a balanced organic fertilizer.
• Choose a site for planting that receives plentiful sunlight (at least 6-8 hours).

3. Plant watermelon seeds directly in warm soil

Wait to plant watermelon until the soil temperatures reach 21ºC (70ºF). Plant outside 2-3 weeks after your last frost date. Sow 3-4 seeds 2.5cm (1 inch) deep, 1.2-1.5m (4-5 feet) apart. Water well with seaweed emulsion after planting. Thin to the strongest plant when plants have 3-4 leaves. 

If using square foot gardening, plant shorter bush varieties, plant at the end or corner of a bed, and plan on one plant per 3-4 squares. 

The best time to plant in the low desert of Arizona is from February 15th through March.  

If desired, start seeds indoors one month prior to planting outside. Because watermelons can be very frost-sensitive, it’s important to avoid planting until there is no danger of frost.

4. Water watermelon correctly for the best-tasting watermelon

5. Feed watermelon throughout the growing season

6. Mulch the plant and protect the fruit

Mulch plants well to prevent weeds and conserve moisture. 

Once the fruit is set, use cardboard or a melon cradle to lift the fruit off the ground to protect it from pests and diseases. 

Growing watermelon vertically? Use melon hammocks to support growing fruit. I use zip ties to attach the melon hammock to the trellis.

7. Harvest watermelon at the right time

Knowing when a watermelon is ripe is often the most challenging part of growing them. Here are a few things to look for: 

• Three tendrils along the stem (going back to the root) end are brown, dry, hard, and curled.
• The underside of the watermelon turns creamy yellow or white.
• Low-pitched thump when you hit it lightly – practice thumping unripe melons to hear the difference.
• The sheen of the watermelon changes from slick to dull looking.

Comment below if you have questions about how to grow watermelon, or share tips and varieties of watermelon you’ve tried and enjoyed.