Growing Watermelon

Summer is all about watermelons – biting into the cool flesh and having the juice run down your chin and onto the lawn (because eating watermelon inside should be banned!). Is there anything better than the cold, pink flesh of a perfectly ripe watermelon?

We absolutely love the newer, family-sized watermelons that are available these days. About the size of a soccer ball, these ‘personal watermelons’, as they’re referred to in the industry, are an up-and-coming thing.

Up and Coming Varieties

Earlier in the year the Grow to Eat team visited the Starke Ayres Farmers Day, held at their Kaalfontein Research Farm. There we were able to meet with all of the Starke Ayres team, including the various product specialists. We’re not exaggerating when we say that all these guys do is research and farm their specific crop – all day, every day.

Riaan Duvenhage is the Starke Ayres product specialist for melons, so we asked him to share just a tiny bit of his watermelon knowledge with us.

Note: Riaan deals with the commercial side of things, so not all the varieties he mentions are available to the home gardener.

“There are two main types of varieties in South Africa. The first is the ‘All Sweet’ types, which are the most popular types. They produce long and very large fruits and the most popular varieties are ‘Star 9906’, ‘Turbo’, and the new-to-market ‘Santa Matilde’.”

“The second group is ‘Crimson Sweet’, the fruit of which is more oval in shape. These are more popular in the south of the country, particularly in the Western Cape.”

“A third type is the ‘Jubilee’ watermelons, which have a different skin type to the other two, more popular melons. Of these, ‘Tiger’ is the most popular because it matures earlier than the others.”

Then there are the ‘Personal’ types, which are slightly bigger than a sweet melon (like a spanspek) and their appeal lies in the fact that they’re small enough to fit in the fridge whole; they can be eaten in one sitting by a family, and they don’t break the plastic bags you’re trying to carry them in. Probably the most popular ‘Personal’ watermelon is ‘Boxy’, which produces round fruit of about 4 – 8kg in weight and has firm and fragrant flesh. Some of the other ‘Personal’ varieties offered by Starke Ayres are ‘Vanessa’, ‘Valdoria’ and ‘Ivona’, while ‘Fashion’ is a larger round watermelon. ‘Sugarbaby’ is a smallish round heirloom watermelon that is very popular with home-growers.


Seed should be sown in spring through to early summer. While watermelons prefer sandy soils, they can actually be grown in just about any soil that drains well. For best result, dig the soil over deeply, as the roots develop to 30 – 40 cm deep.

Add generous quantities of organic matter, and once planted don’t overwater. In fact, once the fruit is the size of a tennis ball, limit watering to when the soil is completely dry, and don’t water at all from about a month before harvesting.

Bees are needed for pollination, and the plants will have both male and female flowers on the same plant.

Varieties available to the home gardener are ‘Crimson Sweet’ and ‘All Sweet’, ‘Congo’, ‘Sugar Baby’, available in seed form from either Stark Ayres and Mayford. The heirloom seed companies like Living Seeds often have a wider variety of interesting watermelon seeds such as ‘Moon and Stars’ and ‘Georgia Rattlesnake’. ‘Moon and Stars’ yellow is a great yellow-fleshed variety.


Harvesting generally occurs about 11 – 17 weeks after planting, and if you harvest carefully you will get a second set of fruit. The fruit should be fully ripe at harvest, when the flesh is mid-pink to deep pink or even red in colour (dependant on the cultivar – there are even some yellow-fleshed watermelons), and firm and crisp.

Riaan’s tip for when to harvest is, “to look at the stem where it joins the flesh. When it is ripe there will be little cracks around the stem, that looks like a wagon wheel. As soon as you can see the wagon wheel it is mature.” Other people suggest that the ground spot (where the fruit lies on the ground) should be a buttery yellow, or the fruit should make a dull sound when smacked. Leaves and tendrils drying out near the fruit are also indications of ripeness.

When harvesting, cut the stem a few centimetres from the fruit using a sharp knife or secateurs.


There are dozens of ways to use watermelon, but nothing beats simply biting into a thick triangle of the cold flesh. Otherwise the flesh can be added to smoothies, fruit salads, used in sorbets or blitzed with ice for a refreshing drink. You can also use the rind in a preserve or pickle.

The Gardener