Wondering how to control pests on your plants without harmful and toxic chemicals? Try these natural alternatives to pesticides.
In my first proper growing year, caterpillars stripped my kale bare, aphids
decorated young foliage like stubborn festival glitter and snails and slugs
munched happily through my ambitious hopes of self-sufficiency. If I didn't work for an organic vegetable delivery scheme, I might have rushed out to buy whatever potions promised to do away with these critters. Instead, I enjoyed the influx of butterflies
, left the slugs to the beetles and looked for eco friendly alternatives to pesticides
. The kind of methods that would protect my hopes for the garden without killing its inhabitants.
Can you guess the top 10 garden pests?
What are pesticides, and are they harmful?
Pesticides are chemical substances designed to destroy pests
. It shouldn't come as a surprise that aggro and garden chemicals developed to kill pests might also be harmful to unintended targets, including the very pollinators our global food supply depends on.
Studies exposing the toxic effects of neonicotinoids on bees, insects and human health have led to all but two - acetamiprid; and thiacloprid being banned in the EU. Thiacloprid is being phased out, which would leave just acetamiprid - the active ingredient in Bug Clear Ultra. However, a recent government decision to approve the use of neonicotinoid thiamethoxam on Sugar Beet
seed has left wildlife organisations reeling.
Insect populations have plummeted by 25%
in the last 30 years, but there is reason to be hopeful. Recent research found that home gardens provide as much as 85%
of food for our pollinators. This means what we do in our gardens, however small, has the power to reverse - or strengthen this figure.
Pest control is available at the click of a button, but that doesn't make it safe, says Susan Mulvihill. In a recent Epic Gardening
podcast, the Vegetable Garden Pest Handbook author said the main issue with garden sprays is "they're non-selective", meaning you'll not only kill your pests but the very insects that could have fixed the problem for you.
Just like fungus gnats
are a sign of an overwatered house plant, persistent pests are a sign something is out of kilter. What if the pest isn't the problem but a symptom of our way of gardening? One major thing we can do is avoid mono-crops by planting mixed borders, just like nature intended. Read on for our 10 tips on how to keep unwanted wildlife at bay.
1 Feed your soil
Healthy soil = healthy plants, which means plants that can withstand whatever nature throws their way. Use a peat-free compost, topped up with a balanced diet of leaf mould, mulch and preferably homemade compost. Additionally, swap artificial fertilisers for organic certified fertilisers and remember to dilute accordingly. If you're watching the pennies, consider mixing your own comfrey tea. You can also perk up your soil with green manures.
2 Choose pest-resistant crops
When browsing seed catalogues, you'll naturally be drawn to what you eat and what looks good, but you should also pick varieties that have been bred to be pest and disease resistant. The Garden Organic Network recommends Blight resistant potatoes such as 'Remarka' and 'Sarpo', and root aphid resistant lettuces such as 'Milan'.
3 Rotate your crops
On large scale, organic farms, farmers split their crops up and rotate them to avoid pests getting a taste for the spoils. In 2014, research
by Scotland’s Rural College found that growing legumes in a rotation helped control weeds
, reduced pests and improved the soil structure. But you don't need acres to incorporate crop rotation as part of your plot. Get to know which vegetables belong to which family and switch up where you plant them every year.
4 Sacrifice plants, not pests
When planning your garden, plant a mixture of flowers that will attract predators and decoys. This will distract hungry pests from your main crops. Try to avoid overcrowding as this could lead to overspill (when pests jump from your companion plants to your main crop!) and means your plants are competing for light and nutrients. Get it right, and this will not only look visually impressive but create a more balanced system where your garden can take care of itself, and you can put your feet up with a cuppa.
Plants used as a pesticide alternative include Nasturtiums for black fly, lettuce as an underplant to distract the slugs and Winter Cress, the diamondback moth
lays its eggs on the leaves – instead of on the leaves of brassicas.
Read up on companion planting here:
5 Relocation, relocation, relocation
Slug pellets will be consumed further down the food chain and could eventually end up killing hedgehogs. Instead, relocate slugs and snails (a 20-metre distance
has been shown to overcome the homing instinct) or leave them out for the birds. Any eggs you discover can also be scattered for the birds to enjoy.
6 Encourage gardener's little helpers
A colleague once told me she was throwing woodlice
off her balcony
as they were eating all of her plants. Woodlice mainly eat dead matter and are rarely anything to worry about. But my colleague's reaction isn't unusual. The gardener is bombarded with quick fixes and soon forgets the food webs we learnt about at school. But if we take the time to identify the 'pests' on our patch, we will soon realise we should welcome them and acknowledge their attributes.
Use Candide to help you identify any critters you're unsure of, and check out this resource on the beneficial insects our gardens need to thrive; some might surprise you.
Don't see your bolted crops as failures, but as food for the bugs, you want to attract. No dig grower Stephanie Hafferty
does this with her brassicas. Bolted coriander and fennel can attract beneficial predators as well as the following flowers:
7 Create your own organic pesticide
Neem oil, soapy water, and garlic sprays are popular natural alternatives to pesticides.
Instead of splashing out on toxic sprays, you could make your own natural remedies from stuff you've already got in your kitchen cupboards. However, it's important to remember that 'natural' doesn't mean harmless. With all sprays, whether natural or synthetic, we'd advise spraying at dawn or dusk when you're less likely to zap pollinators accidentally.
This article shows you how to make a natural bug repellent using just a bulb of garlic, water, and an old spray bottle.
8 Put up barriers
Net and plastic bottle cloches are great at keeping pests such as carrot fly
, leaf weevils
out. Remember, the finer the mesh, the more effective it will be. Other gardeners swear by copper rings and beer traps. Slugs and snails are said to be deterred by eggshells, coffee granules and sawdust.
9 Remove unnecessary hiding places
Raised planters look great but aren't always necessary. Plant direct into the soil if you can and regularly check your containers as they are ideal laybys for snails and slugs on their way to your plants.
10 Tidy less, plant more
Pristine gardens with neat edges and manicured lawns leave scant places for the predators you want to woo. Rotting wood, leaf litter, and rock piles are excellent hiding places for beetles and other useful predators and their prey too!
Here are some common 'pests', with what you can do to attract their predators.
Add a birdbath, feeders and bird boxes to attract birds, while a mixed flower border will attract ladybirds, lacewings and hoverflies - all keen for an aphid-buffet.
Ground cover plants, log piles and leaf litter will provide shelter for slug-eating centipedes
and ground beetles
. A pond will bring frogs and toads back to your garden. Allow weeds such as Fat Hen to grow as it provides ground cover for Ground Beetles.
How to deal with common critters you might encounter on your houseplants
How do you control pests? Let us know your tips in the comments.