Garden prep is important
Proper preparation of your garden is key.
Watermelons require well-draining, sandy, loamy soil.
Choose a sunny spot in your garden, as they love warmth and need plenty of sunlight to grow.
A site that receives at least 8-10 hours of direct sun each day will suit them well.
Remember, they also need some wind protection, so plan for that.
Add compost or well-rotted manure to improve soil fertility, and it will give your watermelons a good start.
Sowing watermelon seeds
The best time to plant watermelon in New Zealand is from late September to early November, just as the spring temperatures and soil begin to warm up.
The soil needs to be over 20C.
Sow the seed directly into the ground about 2 cm deep and about 100 cm apart.
You can start seeds indoors in pots 4-6 weeks earlier and then transplant them into your garden once the risk of frost has passed.
If running out of time to grow seed, your garden centre will have a good range of plants available.
The best place to plant
If you have a small garden, consider growing watermelons on a vertical frame using a trellis and lots of support.
This will help air circulation around the plants, which is beneficial for preventing diseases.
Remember to support any hanging fruit as it gets large.
If you have some spare flat ground around your compost bin, you will find they will grow well there as well.
I have also grown them in old tyres.
What watermelons need
The plants require consistent moisture, especially during their early growth stages.
However, it’s crucial to avoid letting them get waterlogged as this can lead to root rot.
Mulching around your plants can help retain moisture during hot summer days, while also keeping the weeds at bay.
Fertilise after the seedlings have developed their first true leaves with something like liquid seaweed fertiliser.
When is my watermelon ripe?
Growing time can vary from 80 to 100 days after planting, depending on the variety.
Look for several signs to determine if your watermelon is ripe.
The tendril closest to the fruit will turn brown and dry out, the surface should have a consistent colour, and the bottom spot, where it was resting on the ground, should be a creamy yellow colour.
A gentle tap will produce a deep, hollow sound when it is ready to pick.
Tips
Choose the right variety for your area.
Popular varieties in New Zealand include Sugar Baby, Moon and Stars and Crimson Sweet.
Watermelons are cross-pollinating, and female flowers need male pollen for fruit to form.
Planting in groups with bee-friendly flowers such as borage, nasturtium, lavender, and colourful marigolds will attract pollinators like bees.
This will be an advantage for your other plants in the garden as well.
Ensure regular watering during the flowering phase to promote fruit set and ensure ample space between plants for both growth and air circulation.
Growing watermelons in your garden is both rewarding and delicious, a perfect way to enjoy fresh, sweet produce during the warmer months.
With a bit of preparation, regular care, and as much sunshine as possible, you’ll soon be harvesting plump, juicy watermelons in no time.
