I live in the UK and I have dabbled at growing melons in my unheated greenhouse a few times over the years, with mixed results. This year however, I have found a UK based seed company that offers watermelon seeds for the UK climate. So I’m looking at watermelon companion plants and I’ll share them with you here.
What Are Watermelons?
Watermelons are members of the curcubit family which includes pumpkins, squash, melons, cucumbers, and gourds. They are sweet flavoured and as the name suggests, very juicy. Watermelons develop differently to other members of the same family.
They have less dense flesh with a much higher water content and sugar content than squashes. Cucumbers also have a high water content but not as high as watermelons, and their sugar content is lower too.
Watermelon Companion Plants
The following list is suitable for all members of the curcubit family but with special emphasis on watermelons.
Legumes and Watermelons
Members of the legume family including peas and beans. These plants fix nitrogen in the air so will not take nitrogen from the soil. Leaving all that extra food for the hungry watermelon plants.
Try to grow bush variety beans and lower growing peas to not block sunlight from the watermelon plants.
Alliums and Watermelons
This family includes onions, garlic, leeks, shallots, and chives. Alliums deter many pests including aphids (black fly, white fly etc…), flea beetles and many others but these are the specific ones that can affect watermelons.
Radishes and Watermelons
These wonderful little plants make great companions for watermelons. They don’t take up much space, are harvested long before the watermelons are in need of more space, and they provide ground cover to suppress weeds. Radishes attract flea beetles so can be grown as a sacrificial crop but don’t grow them too close to watermelons if flea beetles are a problem.
More importantly radishes deter squash beetles which can cause untold devastation to your watermelon plants. The first evidence will be the death of the plants so prevention is definitely better than cure.
Marigolds and Watermelons
A good all round companion plant, the marigold attracts beneficial pollinators like bees and butterflies. They also deter many harmful pests including aphids and nematodes. Slugs and snails are also attracted to marigolds so keep this in mind and don’t grow them too close to watermelons.
Click this link to find out more about companion planting marigolds.
Oregano and Watermelons
This aromatic herb will improve the health of watermelons and any other plant just by growing in companion with them. It’s strong smell will help to disguise the watermelon plants from harmful predators whilst attracting good pollinators like lacewings and hoverflies. It’s also of much use in the kitchen.
Nasturtiums and Watermelons
Another great plant for repelling squash beetles and for attracting helpful pollinators. Be warned though, they also attract aphids so grow at the edge of plots to reap the benefits.
Borage and Watermelons
A wonder plant, as far as I am concerned you can never have too much borage. This dynamic accumulator digs deep for extra nutrients and attracts beneficial pollinating insects to your plot. Borage also repels squash beetles and cucumber beetles which can kill all members of the curcubit family.
Zucchini (courgettes) and Watermelons
These Summer squashes benefit from the same growing conditions as watermelons and so can be grown in companion with them. The only caveat to this is if you were wanting to save seeds from either crop as they will cross pollinate.
Winter Squash and Watermelons
As all squashes need similar conditions to grow, Winter Squash and Watermelons will make good companions. Unfortunately as they are of the same family, they will cross pollinate which is a problem if you are seed saving.
Sweetcorn and Watermelons
Part of the original three sisters companion plants, sweetcorn can be grown in companion with watermelons. Just remember that watermelons need full sun to develop into tasty fruits so allow them enough sunlight. The sweetcorn will benefit from the spreading nature of the watermelon vine to suppress weeds.
What Not To Grow With Watermelons
Never grow potatoes with watermelons
Due to their need for lots of nutrients, potatoes will compete with watermelons and both plants will suffer. Also many varieties of potatoes need lifting before the watermelons are fully grown. This will cause disruption and damage to the watermelon plants and subsequent crops.