Watermelons are an incredibly popular fruit, but you haven’t tasted real watermelon until you’ve had a homegrown one!
Considering how massive the plants (and fruit) can get, it’s entirely possible to grow them on a balcony. Read on to find out how.
Although you can grow watermelons in USDA Hardiness Zones 3-11 (which is most of the US), they thrive best in warmer climates. Watermelons have a long growing season – up to 3 months. So, if your climate is on the colder side, choose a quick-growing variety, such as Sugar Baby or Yellow Doll.
Watermelons are creeping vines that typically spread out over the floor. However, you can easily grow them vertically up a wall or your balcony railing, providing you use a trellis and plenty of support ties.
Sunlight: Full sun
Grow in pots: Yes – 5-gallon or larger
Grow indoors: No
Soil type: Well-draining
When to plant: Depends on climate
Plant your watermelons about 3 weeks after the last frost, once the soil temperature reaches at least 70F. In warm climates (zones 10-11), you can plant them directly in the soil in later winter or early spring.
In colder climates, you’ll need to start them indoors and then pot them out. Note that watermelons don’t transplant well, so you’ll need to use a non-invasive germination method.
The easiest is to take a toilet roll tube, fold one end up, and fill it with soil. Germinate a seed in the soil and then plant it directly into the big pot. The cardboard tube will rot and saves you from disturbing the seedling.
While you can get watermelon seedlings from a gardening store, they’re best grown from seed for the reasons mentioned above. Germinating the seeds is super easy and takes less than a week.
Here’s what you’ll need to grow watermelons on your balcony:
- 5-gallon pots (such as this)
- Potting soil (such as this)
- Watering can
- Trellis (such as this) and support ties
1. Fill your pots with soil, leaving it fairly loose.
2. Germinate your seeds. In warmer climates, do this directly in the big pot. Poke a hole in the soil with a pencil, drop in a seed or two, and cover over. You’ll want 3-4 seeds per pot.
3. Once the seedlings have grown their first set of proper leaves, look for the strongest and remove the rest.
4. If you’ve germinated indoors, transplant the whole seedling pod into the pot – one in each.
5. Set up your trellis, making sure it’s tied to a wall or railing.
6. As the plant starts creating vines, tie them to the trellis with plenty of support.
7. You might need to pollinate the flowers yourself, which you can do by shaking the plant or rubbing the flowers with a Q-tip.
8. Make sure the melons are loosely tied to the trellis once they begin forming.
Watermelons need a lot of watering (it’s in the name, after all). Keep the soil moist but not wet, and ensure water can drain out the pot. In containers, you might find yourself watering the plants once or twice a day.
Once the fruits set, though, reduce watering for sweeter melons. Fertilize weekly with an all-purpose fertilizer in the beginning. After flowering, switch to a liquid seaweed fertilizer.
For best results in a container, only grow one main vine per plant, trimming off side shoots.
Growing watermelons on a balcony is surprisingly easy, making it a great project for kids. Despite being big plants, growing them vertically means you get the most from them, even in compact spaces.