Gardening: repelling pests and fertilising garden plants with minimal environmental harm
During the summer months, there is nothing more relaxing than sitting out in the garden during the evening sunshine – unless you are surrounded by biting insects. This is made all the more difficult when trying to avoid negative environmental impacts that can be common side-effects of insect repellents. This How To provides some suggestions for keeping gardens as the wonderful relaxing space they should be, without literally costing the earth.
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Repelling biting insects
Nothing ruins an evening in the garden quite as much as a cloud of midges hovering between the patio and the door back into your dwelling. There are going to be bites and, by lunchtime tomorrow, they will be itching to the point of driving the victims mad! DEET (N,N-diethyl-meta-toluamide)-based insect repellent insect repellent is excellent for keeping biting insects away, but affects honeybee chemo sensing.[1] It can also (rarely) cause adverse skin reactions – particularly if you already have sensitive or damaged skin. These factors make it less desirable and humanmade repellents are generally very effective against most insects – whether you want them around or not. |
Figure 1. Pelargonium hortorum ‘Americana Dark
Red’ (red scented geranium).
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Choosing the right plants could drastically reduce the number of biting insects interrupting the pleasantries of your evening, whilst encouraging pollinators to further improve the niceties. Plants that achieve this include lavender, alliums (including onions), catnip, bee balm, marigolds, lantana, scented geraniums (e.g., Figure 1), ageratum (floss flower), and pennyroyal.
Lavender strongly benefits from cutting and regrowth. Bunches of lavender leaves and flowers can be tied together and hung in a cool, dry area to dehydrate over a couple of weeks. These can then be used as a natural air freshener to bring fragrance indoors.
Some varieties of lavender are also edible – though not all – and can be used to decorate cakes or introduce unusual flavours to sweet treats. However, it is crucial to ensure that you know the specific varieties you have before introducing them to your diet.
Apart from acting as a deterrent for biting insects, many of these plants provide a welcome source of nectar for pollinators. As a result, the population and variety of bees, butterflies, hoverflies, moths, and other pollinators will likely increase in your garden, over time. In turn, birds (and, possibly, bats) will begin to visit where they may not have done so before.
Other plants can provide kitchen ingredients whilst repelling biting insects. Among these are garlic, onions, and sage – which are low maintenance and easy to start from seed. There are also the options of mint, rosemary, basil, lemongrass, fennel, and thyme.
Trimming the newer stems and leaving the older ones gives your garden the fragrance that keeps most biting insects away, whilst allowing the addition of flavour to your food. Eucalyptus is also fragrant, repels biting insects without adverse effects to pollinators and can (with proper training) be used for medicinal purposes.
Reference
1. N. K. Singh, N. Eliash, Y. Kamer, I. Zaidman, E. Plettner, V. Soroker, The effect of DEET on chemosensing of the honey bee and its parasite Varroa destructor, Apidologie, 2015, 46(3), 380. https://doi.org/10.1007/s13592-014-0330-1.
Lavender strongly benefits from cutting and regrowth. Bunches of lavender leaves and flowers can be tied together and hung in a cool, dry area to dehydrate over a couple of weeks. These can then be used as a natural air freshener to bring fragrance indoors.
Some varieties of lavender are also edible – though not all – and can be used to decorate cakes or introduce unusual flavours to sweet treats. However, it is crucial to ensure that you know the specific varieties you have before introducing them to your diet.
Apart from acting as a deterrent for biting insects, many of these plants provide a welcome source of nectar for pollinators. As a result, the population and variety of bees, butterflies, hoverflies, moths, and other pollinators will likely increase in your garden, over time. In turn, birds (and, possibly, bats) will begin to visit where they may not have done so before.
Other plants can provide kitchen ingredients whilst repelling biting insects. Among these are garlic, onions, and sage – which are low maintenance and easy to start from seed. There are also the options of mint, rosemary, basil, lemongrass, fennel, and thyme.
Trimming the newer stems and leaving the older ones gives your garden the fragrance that keeps most biting insects away, whilst allowing the addition of flavour to your food. Eucalyptus is also fragrant, repels biting insects without adverse effects to pollinators and can (with proper training) be used for medicinal purposes.
Reference
1. N. K. Singh, N. Eliash, Y. Kamer, I. Zaidman, E. Plettner, V. Soroker, The effect of DEET on chemosensing of the honey bee and its parasite Varroa destructor, Apidologie, 2015, 46(3), 380. https://doi.org/10.1007/s13592-014-0330-1.
