How to Grow Watermelons in Containers | Why to Grow Watermelons Vertically in Containers

Seedtolife
7 min readApr 13, 2021

Seed to Life YouTube Channel

Gardeners in you must be very excited as the spring has begun. I know I’m. I can’t wait to get outside to see new surprises in my garden. All the seedlings have started sprouting and spring flowers are blooming. As the temperatures have started rising, to stay hydrated we can grow some juicy watermelons.

History of Watermelons

Did you know that watermelons are ancient fruits that are being cultivated since prehistoric times? They were growing in wild in the Kalahari desert in Africa. Those fruits were not sweet-tasting like today’s watermelons. They were also found in the tombs of Egypt at multiple archaeological sites. These discoveries show that watermelon was being cultivated since ancient times. Inner green and bitter parts gradually were replaced with red mellow parts by selective breeding and advances in agricultural technology. Seedless watermelons were discovered by Japanese scientist Professor H. Kihara.

Growing Climate

Watermelons grow well in a tropical and temperate climate. Last year, I grew some baby watermelons in a container. Usually, summer in my region is harsh and the temperature is consistently is above 100°F. It affects even heat-loving plants like watermelons. But last year, I installed a quick homemade trellis in a 17-gallon container and I could enjoy a refreshing harvest.

The benefits of growing watermelons in containers

  • You can control the amount of space it occupies and also the amount of water. Watermelons like consistent watering. Perfectly watered watermelons are sweeter in taste with juicy pulp.
  • Also, you can protect the plants better by covering them using either a tarp or shade clothe during constant rain and extreme summer heat if the plant is contained.
  • Keeping watermelon plants potted and growing them vertically also saves a lot of space. Planting them in the ground occupies a considerable amount of space since if grown directly in the ground the recommended spacing between two plants is about 6 feet. If you have a big yard then it is not a problem but for urban gardeners, potted plants work the best.
  • The plant is a creeping branching vine. The tendrils are the coiled structures that easily grab onto the trellis helping the vine grow upwards. With the plants wrapping around on the trellis, a beautiful vertical structure can be created in the garden. The vines still can get unruly like a toddler and try to wrap onto the branches of the adjacent plants. So you may need to keep guiding them and if you choose a big fruit variety you may even need to support the fruit to ensure that it doesn’t break off of the vine.
  • When grown vertically in containers, it is easier to protect fruits from animals. I have seen a friend of mine was growing watermelon and rodents used to nibble on the fruits.

Growing Watermelons in the Ground

  • When grown in the ground watermelons can act as a ground cover, somewhat like a mulch, and retain moisture in the ground. The fruits may need extra protection to keep them dry. You can use some straw, cardboard or readymade stands to keep them away from the ground and getting damaged by moisture.
  • The harvest is definitely bigger if watermelons are grown in the ground as plants can grow unrestricted.
  • You can grow bigger varieties easily in the ground.

Why choose a Small Fruit Variety?

  • If you have decided to grow watermelon in containers then I would recommend picking a small fruit variety like baby watermelons. They mature faster compared to the regular varieties.
  • If you have a small family then it is better to grow these tiny varieties because you don’t have to worry about storing the leftover fruit after cutting it open.
  • If you want to avoid sweet fruits for some reason then smaller fruits are better for potion control.

Soil Requirement/ Sun Requirement/

Watermelon like the soil well-draining sandy loam and moist with pH between 6–7 i.e. slightly acidic. Watermelons are heat and sun-loving plants.

Optimal Temperature

They are not at all cold tolerant. They do not well when the temperature drops down to 50°F and below. At these lower temperatures, plants may survive but the fruit doesn’t mature. The optimal temperature for growth is 65–95°F. I live in Texas where summers are exceptionally hot and the temperatures are in the mid to high hundreds and it is normal to have heat waves lasting up to a week or more at a time. In my zone, ie zone 8, Watermelon plants do well from spring-early summer and then again late summer-early fall in my region. During the extreme heat of summer, the leaves start drying up and turn yellow. You might even feel that they are not going to survive the summer but they recover as soon as the temperature starts dropping down.

Watering Needs for Watermelons

Watermelons need a good amount of water and nutrients to keep growing as they also grow a lot of foliage too. During summertime, I keep pruning the leaves to divert all the nutrition towards growing fruits.

When to Start the New Plants

Now let’s see when to start the plants. If you have a short summer in your region then you can start the seedlings indoors in late winter, about 6–8 weeks before the temperature in your region reaches about 70°F. At that time they will be ready for transplanting outdoors.

Or start the plants directly outdoors 2–3 weeks after the danger of the frost is over and the temperature is consistently warm. The seed to harvest time for watermelon is approximately 80 days. It is longer for the bigger varieties.

What to feed the plant to get the best fruits?

In the initial period, I want the plant to mature faster so I feed fish fertilizer every 2 weeks for a couple of months and also when I transplant the plants in the final spot I add a mixture of blood and bone meal to provide both nitrogen and phosphorus so that the fruit-bearing and maturation occurs. I also add some azomite to give my plants complete nutrition. The blood and bone meal are long-term fertilizers and I start seeing their result in about 2 months after the application. I frequently feed some compost to my plants.

Are Watermelons Annual or Perennial Plants?

Watermelons are annual plants so you have to start them every year. They can easily be grown from seeds. Unlike a longer growing period, germination time is much shorter, usually between 3–10 days. You can see healthy seeds sprouting only in a couple of days. This year, I’ve decided to grow some of the germinated plants in a raised bed. I’m still planning to grow them vertically though.

Parts of the Watermelon Plant

Roots

Watermelon has a taproot system and the roots are delicate. It matters more when you grow the seedlings in some pot and then try to transfer it in the ground. They can easily get damaged especially while separating the seedlings and if you are not gentle with them while planting.

Leaves

The leaves are partitioned into several parts and look very attractive. But they also attract several pests like aphids, cucumber beetle and several other. Beneficial insects play a key role in taking care of the plants in a safe way. I keep removing the dead and yellow leaves during summertime to reduce the energy needs of the plant.

The stems are covered in hairy structures and they branch. They also have coiled structures on their stems called tendrils that help the plant get support.

Flowers

Flowers start developing after about a couple of months. At first predominantly male flowers develop and once the plant is mature enough to bear fruits, both female and male flowers appear. It is not hard to distinguish between male and female flowers. female flowers have a small fruit-like structure under the flower. If the pollination is successful this tiny fruit becomes a mature fruit. It takes another 1 1/2- 2 1/2 months for the fruits to get ready for the harvest.

How do you know that the watermelons are ready for picking?

It can be tricky to know if the watermelon is ready to be picked or not. If you wait too long then the fruit might fall off from the vine or if picked early, it may not reach its maximum level of sweetness. I keep checking on the fruits mainly the tendril near it. Once the tendril turns brown, you can harvest the fruit. Waiting longer even after the harvest makes the watermelon much sweeter. You can see here the skin is very thin and the fruit is very juicy.

Watermelon Nutrition

About 92% of the watermelon is water. The rest is mainly carbohydrates mainly sugars, anti-oxidants, vitamin A(31%), vitamin C (37%), vitamin-B 6 (5%), and Magnesium (7%). It contains very little proteins. The fat co

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Seedtolife

I’m a gardener for whom gardening is not just a hobby now but has become an integral part of my life. I would like to share with you all the beauty of gardening