Using Nasturtium As Companion Plants – They Make An Excellent Trap Crop In A Veg Garden
Elizabeth is a Permaculture Garden Designer, Sustainability Consultant and Professional Writer, working as an advocate for positive change. She graduated from the University of St. Andrews with an MA in English and Philosophy and obtained a Diploma in Applied Permaculture Design from the Permaculture Association.
Reviewed By COLIN SKELLY
Colin is a Horticulturist and Horticultural Consultant with experience in a range of practical and managerial roles across heritage, commercial and public horticulture. He holds the Royal Horticultural Society’s Master of Horticulture award and has a particular interest in horticultural ecology and naturalistic planting for habitat and climate resilience.
Contributions From EMILY CUPIT
Emily is a Gardening Writer, Photographer and Videographer from Derbyshire, UK. She is the Founder of Emily's Green Diary - a community of more than 75,000 people who share in her gardening journey.
IN THIS GUIDE
Nasturtiums are wonderfully easy flowers to grow and are great for new gardeners and for those growing with the youngest members of the family.
They can, of course, be wonderful as ornamental plants, but another thing to consider is that they also make great companion plants in a vegetable garden – and provide edible yields in their own right.
Nasturtiums make great companion plants because they:
- Attract bees and other pollinators.
- Draw in pest species like aphids, weevils and beetles, serving as a trap crop to keep these pests away from your fruit and vegetable crops.
- Attract predatory insects that like to eat the aphids and other pests mentioned above, to keep their numbers down.
- Have a scent that is said to confuse or repel certain pests.
- Create good ground cover, conserve soil moisture and protect the soil.
- Quickly grow, generating biomass that can be fed back into the system through composting, or chopping and dropping to help improve soil fertility for other plants close by.
Plants That Could Benefit
Nasturtiums, for the reasons mentioned above, can aim many plants in a vegetable garden to a degree.
They are a particularly good companion plant in a vegetable garden for brassicas (e.g. broccoli, brussels sprouts and kale), cucurbits (e.g. courgettes, cucumbers, squash and pumpkins), legumes (e.g. French beans or runner beans) and nightshades (e.g. aubergine, peppers, tomatoes).
Elsewhere in the garden, nasturtiums can also work very well as a companion plant on the sunny fringe of a fruit tree guild.
Companion Planting With Brassicas
When companion planting nasturtiums with brassicas some care is required, since brassicas are hungry plants and will easily be outcompeted by nasturtiums.
However, sowing nasturtiums near brassicas once the plants are reasonably well established can be a good idea.
The nasturtiums can spread below larger brassica plants, creating good ground cover and keeping the soil moist.
They can also help repel or confuse a range of pests such as caterpillars, which can become an issue for these crops.
Companion Planting With Cucurbits
My favourite place to include nasturtiums in my vegetable garden is close by courgettes, or summer squash, or on a trellis alongside cucumbers or larger squash.
Think carefully about spacing, since cucurbits are also hungry plants.
Creating the right level of competition is important.
Having nasturtiums alongside these plants is hugely beneficial because they draw in pollinators when these crops need them around, draw aphids, flea beetles and other pests to themselves as a trap crop, and therefore attract predatory species which keep pest numbers in check.
Companion Planting With Legumes
Alongside nasturtiums and squash growing on a trellis, climbing French beans or runner beans can also be a great addition to the polyculture.
The legumes are a good addition to a polyculture alongside nasturtiums since they will fix nitrogen from the air and ensure its availability in the soil.
While the nasturtiums should help with aphid problems on the beans.
Companion Planting With Nightshade
Tomatoes, peppers and aubergines can also all benefit from nasturtiums when it comes to pollinator attraction and pest control.
Nasturtiums growing as ground cover around the base of tomatoes and other related crops can also be beneficial in terms of retaining soil moisture.
While these are the main families of plants to consider growing nasturtiums alongside, they can be happy bedfellows with a range of other crops too – just don’t grow them with plants too easily outcompeted or smothered by this vigorous growing plant!
Using Nasturtiums Alongside Fruit Trees
Nasturtiums will not be perennial in our UK climate but they might still be included as an annual around the sunny fringes of a perennial guild (and will sometimes self-seed readily, making for an excellent low-maintenance system).
A fruit tree guild is a carefully constructed planting scheme, with plants chosen for their ability to aid the tree at the centre of the guild in some way.
Forest gardens are layered planting schemes designed to mimic a natural forest ecosystem but include plants that are useful to the system as a whole.
On the sunny fringe of a fruit tree guild or forest garden, nasturtiums can look very pretty as ground cover, in addition to providing their services as a companion plant mentioned above.
“Growing nasturtium in a fruit tree guild is a great idea,” shares Master Horticulturist Colin Skelly.
“It tends to work best where it can do its thing and spread freely, which means it can be difficult to manage in a vegetable garden or more formal space.
“The biggest challenge is preventing it from smothering adjacent plants, so plant it alongside robust shrubs and perennials that can cope with the competition.”
