How Many Watermelons Grow Per Vine? [ANSWERED]

So you’ve got it in your head that you want to grow your own home-grown watermelon. But how many plants do you need to grow? How many watermelons per plant?

In a study performed by the UC Master Gardeners of Santa Clara, they grew 17 varieties of watermelon to observe the growth and production rates. During the study, the average number of fruits produced by each plant was 5.7 watermelons. A wide number of factors can influence the number of watermelons your watermelon plants will produce, such as care, weather and growing conditions. We’ll discuss these factors in more detail later – so keep reading.

There is plenty we can take away from the Master Gardeners project. By far the most exciting lessons are the methods they used in their study. By learning the techniques they used for germinating and tending to their watermelon plants, we can hopefully create productive watermelon crops that will replicate their results.

Planting Watermelon Crops: Facts and Tips

Watermelons are a staple at summer gatherings. Whether it is in a smoothie, a star ingredient in a fruit salad, or simply cut up and served fresh – you can be sure it will be a winner.

So, as home gardeners, it only makes sense that we’d have a natural curiosity to see how hard it is to grow our very own organic watermelons!

We did a bit of digging around and put together a quick beginners guide on the facts about growing watermelons at home.

How Many Watermelons Per Plant?

Let’s circle back to the topic at hand – how many watermelons can you expect to grow per plant? If we were to use the Santa Clara Master Gardeners study as a guide – you would expect between 5-6 watermelons per plant (or 5.7 to be exact!).

However, given that we are in the beginning stages of attempting to grow watermelons, we would say a more conservative estimation of 2-5 watermelons per plant would be more accurate. This allows for any mistakes we make along the journey, and the learning curve of mastering the cultivation of a new type of fruit.

How to Grow Watermelons: The Basics

Okay, let’s get into the fun stuff – learning the fundamentals of growing watermelons.

• A lot of Space – Watermelons need A LOT of space. Like pumpkins, watermelons grow on vines (not trees as some people believe) that will sprawl along the ground and garden beds. The best practice for growing watermelon plants is in dedicated garden beds with plenty of space on the sides of the beds for the vines to grow into.
• Hungry Hungry Watermelons – if you want a productive watermelon plant, make sure to provide plenty of food for your crops. Regular fertilizing and plenty of organic decomposed compost will set your heavy feeder watermelon plants up with the best opportunity to flourish.
• Thirsty Thirsty Watermelons – given that watermelons are 90% water, it only makes sense that they need plenty of water while they are producing the fruits. The key is to water your watermelon plants with at least 1-2 inches of water a week. Particularly when they are in bloom and trying to set the fruit. Try not to spray the leaves or fruits with water, otherwise it can attract unwanted pests and diseases.
• Proper Soil – the last fundamental rule in watermelon growing is using the right soil for the job. With plenty of watering happening during their growing periods, watermelons need a rich loamy organic soil with plenty of compost and excellent drainage. The best way to achieve this is to amend the soil BEFORE you plant your watermelon seeds. Add aged manure, seaweed organic fertilizer and compost and mix it in well for the perfect start for your watermelon crops.

How to Thin Out Watermelon Plants

The practice of thinning plants out is used to manipulate where and how a plant uses its precious energy.

The first step in thinning (pruning) watermelon plants is to remove dead or diseased parts of the plant. In doing so, your plant will focus its energy on the productive parts, like flowers and fruits.

The next step is to decide the kind of watermelons you would like your plant to produce. If you prefer larger (prize-winning) watermelons, cull your watermelon plant down to 1-2 vines. This will concentrate the energy into only a few fruits, encouraging larger fruits.

Alternatively, if you are looking for quantity over quality, then leave more vines on the plant. This will result in more average-sized fruits.

What are the Best Watermelon Varieties to Grow?

Here are three of our top watermelon varieties to grow at home

1. Sugar Baby – with a name like this, who wouldn’t want a few sugar babies growing out back? Sugar baby watermelons usually net around 10-20 pounds per watermelon fruit. They are the quintessential sweet watermelon that you can bring along to a picnic or cut up at home after harvest. You may need as much room when growing sugar baby watermelons. Because the vines are compact, and not as wide or sparse as some other varieties.
2. Moon and Stars – for a watermelon that is a bit different and will certainly strike up some lively conversation, you can try growing Moon and Stars Watermelon. This interesting watermelon is characteristic of producing an extremely dark skin, with contrasting yellow spots speckled around the fruit. Like the sugar baby, their vine is more compact than other commercial brands, which makes them perfect for smaller gardens.
3. Crimson Sweet – for our final recommendation, you can’t go past a favorite, the Crimson Sweet Juicy Watermelon. This beauty produces large rotund fruits that can weigh 25 pounds (11kgs) on average. They develop the signature dark and light green stripes, that we are so familiar with, running the length of the fruit. With deep pink flesh that smells fresh and sweet. If you want to grow these in your home, we hope you have plenty of space, because they have long vines that reach up to 10 feet (3 meters) in length.

Watermelon Growing: Care & Maintenance

So we know that we want to grow those delicious watermelons, we understand they need space and good quality rich soil. What do we do once they are growing?

Here are our tips for caring and maintaining watermelon plants.

Flowering

The flowering period for watermelon plants is around one day – which is extremely short.

In order for our plant to successfully fruit, the female flowers need to be pollinated with the pollen from a male flower. Fortunately, watermelon plants produce both male and female flowers.

We don’t know about you, but we think it is awfully risky to leave the pollination process to one day. Hoping with our fingers and toes crossed that there are enough bees or pollinators to complete the pollination process.

To ensure our plants do produce fruit we monitor the flower situation, and when they bloom we manually pollinate our watermelon plants. To do this simply remove the petals from the male flower to reveal the stamen. Then simply rub the pollen on the stamen in the center of the female flowers to complete the process.

Harvesting Watermelons – When is it Ripe?

Let’s say you have a bountiful crop of watermelons growing in your backyard. How do you know when to harvest them off the vine?

Our favorite way of determining when a watermelon is ripe is to lightly drum our fingers on the skin of a watermelon. If the watermelon sounds hollow, then it is ripe.

Another indication that your watermelons are ripening is when the tendrils located close to your watermelon begin to brown and die off. Some gardeners take this as a sign that the plant has finished supplying nutrients to the fruit, and it is ready to be eaten.How To Store Watermelon

How to Store Watermelon?

Once you have harvested your ripe watermelons, they should be stored in a cool area, away from direct sunlight. It would also help to make sure there is plenty of air circulation to avoid any diseases, like downy mildew, from developing.

Harvested watermelons will last approximately 4-6 weeks, before they begin to rot. Once the watermelon has been cut, keep it in a refrigerator to maintain the freshness.

How Many Watermelons Per Plant – Common Questions

How long does it take 1 watermelon to grow?

Although instructions on watermelon seed packets indicate watermelons will take between 70-100 days. A study of 17 different varieties of watermelon, by the Santa Clara Master Gardeners, revealed an average of 121 days for one watermelon to grow.

Of course, there are many factors that will influence this duration, such as weather, growing conditions and maintenance provided.

How much space do you need for a watermelon plant?

Watermelon plants require a lot of space. Like pumpkins, they produce sprawling watermelon vines that cover the ground. Each vine can reach up to 13 feet (4 meters) in length, and each plant can have up to 4-5 vines.

With all this in mind we suggest allowing up to 20 square feet of garden space for each watermelon plant.