How to Grow Watermelons


Learn How to Grow Watermelon Plants in Your Garden

Watermelon is a popular summertime, thirst-quenching fruit. Certainly, more gardeners would grow watermelon plants if only they didn’t take up more space. Well, the good news is that there are space-saving varieties that just might perfectly fit your garden plans. So, read this guide on “How to Grow Watermelons”, then buy some bush variety watermelon seeds, and you are on your way to your first homegrown watermelons! 

Watermelons are perfect for hot summer days, parties, picnics, and much more. Don’t forget to have a pit spitting contest when you serve watermelon….outdoors, please. Laugh if you will, “Pit Spitting” is a serious business, errr game. “Watermelon Pit Spitting” contests, with prizes, are common at summer community picnics and festivals.

The entire watermelon is edible. The rind can be pickled and is also used in stir-fries, too. And the seeds can be roasted and eaten as a snack, similar to pumpkin seeds.

The large, oval watermelons that first come to mind, require a lot of space, and a long growing season. That’s why most home gardeners don’t allot precious garden space for them. The much smaller, but equally sweet baby or “bush” variety that requires about 1/3 of the space, is popular in home gardens.

Did you know? Growing Watermelons is serious business. Watermelon competitions or “weigh-offs” are a common event at fall festivals. Many pumpkin weigh-offs include a giant watermelon category, complete with prizes for the largest melon. Just how big can a watermelon grow? Giant Watermelons can grow hundreds of pounds! The world record watermelon is 350.5 pounds, grown in 2013.

There is also a day set aside in honor of the watermelon… August 18th is National Watermelon Day. It’s just about perfect timing for this very special day, as your garden melons should be ripening.

Varieties of Watermelon

  • Standard watermelons are usually 20 to 30 pounds or more and are oblong-shaped.

  • Baby or bush varieties are round and much smaller. They weigh anywhere from a couple of pounds to ten pounds.

Popular Varieties: Some of the most popular varieties include:

  • Black Diamond – Almost black, bruise-resistant rind with sweet and juicy flesh. Fruit weighs 35-40 pounds.

  • Bush Sugar Baby – The home gardener’s favorite.  The space-saving bush grows just 3 1/2 feet long. The round fruit grows about 12 pounds and fits in your refrigerator.

  • Congo – Gigantic fruit grows 40 pounds or more. Luscious red flesh with high sugar content. Oblong, medium-green melon with dark green stripes.

  • Crimson Sweet – Exceptionally sweet, deep red flesh, and distinctive, dark green, striped rind. Round fruit grows up to 25 pounds.

  • Moon & Stars – A very sweet heirloom watermelon with red flesh, growing 30 to 40 pounds.

Watermelon Plant

How to GrowWatermelon - Planting Seeds

Starting Watermelon Seeds Indoors

If you have a short growing season or want to get a head start, plant watermelon seeds indoors in individual containers or pots. We recommend using peat pots or peat pellets, which can be planted directly in the garden with minimal transplant shock. Plant one to two seeds per pot.

Starting Watermelon Seeds Outdoors

Sow watermelon seeds in hills or rows. For regular watermelons, sow three to four seeds per hill, spacing the hills eight to ten feet apart. Space the rows ten feet apart or more, if you have room. Thin watermelon seedlings in each hill, to two seedlings one week after they have germinated. When planting in rows, space the seeds four to six inches apart and thin seedlings to ten to twelve inches apart. For bush varieties, final spacing can be cut in half or even more if you are tight for space.

Important: Make sure you know how many days you need to reach maturity for the variety you buy. Give a little more time than the seed packet suggests to reach harvest, before that first killing frost.

How to Grow Watermelon Plants - Season Long Care

Watermelon plants need full sun to grow healthy vines and big fruit. Plant after the last frost date for your area. Watermelons are heavy feeders. Add generous amounts of manure, compost, and leaves to your garden. Work the soil well. Make sure it drains well.

Ideal soil pH: 5.5 – 6.5   More on soil pH

Fertilize regularly. Use a high nitrogen fertilizer until flowers form. Then, switch over to a high phosphorous and potassium fertilizer. We also recommend the use of liquid fertilizers and foliar feeding.

Watermelon plants like lots of water. There is no surprise here. Make sure to add water during dry spells. Keep the soil moist at all times.

Weeding is also important especially early in the season. Weeds will compete for moisture and nutrients.

Tip: For extra big watermelons, cover the vines with garden soil. This will promote secondary root growth where leaf stems meet the vine. It can add many pounds to the fruit.

Also, see:

Plant Problems

Soil Temperatures

Ideal Soil pH for all vegetables.

Insects and Pests

Watermelon is susceptible to a variety of pests. Cucumber beetles are perhaps the watermelon’s pumpkin enemy #1. Cucumber beetles will rob the plant of nutrients, eat pollen, and spread plant disease. A variety of other pests will also enjoy the watermelon plants in your home garden. Use of insecticides early is important, especially against the dreaded cucumber beetle.

Plant Disease

A wide variety of viruses and funguses can affect your crop. Of particular note is powdery and downy mildews. Maintaining a healthy plant is the first step in disease control. This includes weeding, pruning, and proper spacing to allow good air circulation, especially in wet and humid weather. Fungicides can be effective if used early.

Plant Problems – Diagnosis, causes, and cures for many common plant problems.

How to Grow Carrots - HarvestTime

Days to Maturity: 80 to 90 days for baby bush varieties, and 90 to 100 days or more for the larger varieties.

So, how do you know when a watermelon is ripe? Most people tap on the fruit, and listen for a dull thump. If you grow many of them, this is an art form.

Other signs include:

  • Ceasing of growth

  • Yellowing of the underside

  • Drying or shriveling of the stem near the base of the fruit

Watermelon Humor: When do you start on red and stop on green? … when eating watermelon.

Plant Hardiness

Watermelon plants are a tender annual. Spring and fall frosts will kill the plant. They thrive in hot weather. Their growth will slow to a crawl during cold nights. Provide plenty of protection for your tender seedlings. Use hotcaps or coldframes on cool nights or when frost is a possibility.

A fall frost will not damage the fruit and it can still be harvested.

Related Articles

Growing Watermelons – more information from Garden Hobbies.

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