Helle Troelsen, a Danish horticulturist, gives her opinion on how you can attract insects to the garden with the right plants and deter mildew, lice and other pests.
Written by Nanna Stærmose
Edited by Louise Curley
Photos: Helle Troelsen
There was a time when gardeners would use a cocktail of chemicals to control pests and diseases in the garden, but as increasing evidence has shown that these chemicals are toxic, not just to creatures considered pests but also to beneficial insects and the wider environment, gardeners have turned to organic growing techniques.
One of these is known as companion planting, which uses certain plants to deter pests from crops.
Here are some plant partnerships to try:
- Nasturtiums and cucumbers – nasturtiums are said to repel cucumber beetles.
- Summer savoury and broad beans – this aromatic herb masks the smell of the beans from broad bean aphids.
- Hyssop and brassicas – the fragrant foliage of hyssop acts as a repellent to cabbage white butterflies
- Tagetes and tomatoes – French marigolds not only look pretty but their pungent foliage will protect greenhouse tomatoes from whitefly.
- Basil and tomatoes – this classic flavour combination also has pest control benefits as the whitefly will head to the basil before the tomatoes.
Filling a garden with flowers that are attractive to insects, such as hover flies, ladybirds, lacewings and wasps, will also help to control pests as these beneficial insects and their larvae will feed on pests such as aphids.
- Umbellifers such as fennel, dill and ammi
- Garlic chives
- Poached egg plant
Mint can also act as a deterrent to ants, but you need to keep the roots of mint restricted in a container otherwise it will become invasive.
Om Nanna Stærmose
Nanna is the Danish writer of many of the articles in the Greenhouse Forum.
Nanna visits happy greenhouse owners and tells their stories about basic cultivation, but also those stories that are more oblique.