While insects are a valuable part of our gardens’ ecosystems, sometimes they end up tucking into our vegetable harvests or eating their way through our flower buds before they bloom.
These moments can have us reaching for the insecticides. However, filled with toxic chemicals, commercial insecticides often stand at odds with the sustainable garden ideas that we want our plots to embody.
This is where homemade insect sprays and deterrents come into their own. Created from items you would find in your store cupboard, they are quick and effective ways to ward bugs off your prized plants.
‘Homemade garlic, nettle, soap, tomato and basil sprays are effective against aphids, mites and thrips. The aim is not to kill off all the insects in your garden, but rather aim for a healthy ecosystem,’ says garden expert Leigh Clapp.
Bug sprays – 6 homemade recipes for plants
Bug sprays should only be used as a short term solution – at the same time as treating pests, think of adding other plants to your garden that will encourage insects and animals that prey on the problem bug.
‘Disaster-proof your garden through plant diversity. The wider the range of plants, the less they are plagued by pests, so that if a disease or pest occurs only a limited number of susceptible plants will be affected,’ continues Leigh.
For example, if you want to get rid of slugs, can you attract more birds? If you need to get rid of aphids, could you plant angelica, fennel and dill nearby to attract ladybirds? There are lots of different companion planting ideas that will help you to reduce pests in your plot. By creating a balanced garden, you will find that you have less and less need for bug sprays.
Before using any of these bug sprays on your plants, always do a patch-test. Spray a small amount onto a few leaves of the plant and wait 24 hours to see if there is any damage. Avoid using any foliar sprays during the heat of the day as the exposure to the sun can cause leaf burn.
1. Insecticidal soap
A popular bug spray for treating a wide range of pests, homemade insecticidal soap, consists of soap, oil and water. Homemade insecticidal soap is often the first port of call for many gardeners as the ingredients are all store cupboard essentials.
To create insecticidal soap combine one cup of vegetable oil with one tablespoon of dishwashing soap or pure Castile liquid soap. For this method, as well as any others that call for dishwashing soap, avoid those that contain a degreaser or bleach as these can cause more harm than good. Use this oil and soap mixture as a concentrate and dilute one teaspoon with two cups of warm water into a spray bottle. Once mixed with water, the solution’s efficacy will only last for a day.
Insecticidal soap is one of the best ways of getting rid of aphids, as well as lacebugs, leafhoppers, mealybugs and thrips.
2. Neem oil bug spray
An organic insecticide, neem oil has seen a rise in popularity as a method to treat everything from insects through to fungi.
‘Neem oil has been used in India for thousands of years and is a trusted method to keep on top of pests, without any of the nasties,’ explains John Maree, co-owner of OxyPlants. ‘A spray of Neem oil on the tops and undersides of your plant’s leaves will help remove several pests, including mites, whitefly, aphids, thrip, and mealybugs, at every stage in their life cycle. Using neem oil also helps to prevent powdery mildew, too.’
To use neem oil as a homemade bug spray mix one to two tablespoons of pure, cold-pressed neem oil with a gallon of water. You can also add one to two teaspoons of dish soap to the mix to help the neem oil adhere to the plants.
Alternatively, you can use neem oil as a root soak to treat root rot. Mix one gallon of water with two tablespoons of neem oil and one teaspoons of pure Castile liquid soap (to help the neem oil adhere). Apply a small amount as a test and wait 24 hours. If all is well, then apply two or three cups to the soil around the plant, then continue the treatment as a replacement to the watering cycle.
A benefit of using neem oil over other pesticides is that it doesn’t harm birds, pets or beneficial insects. This is because neem oil gets absorbed into the plant’s tissue rather than just sitting on the surface and so only affects any insects that ingest the plant.
It seems that there is no end to the abilities of vinegar, especially when you take into account the numerous ways of cleaning with vinegar, but did you know that it can also be used as a bug spray?
One of the easiest homemade bug sprays, simply mix one cup of white vinegar with three cups of water. You can also add half a teaspoon of dishwashing soap to help the solution adhere. Shake thoroughly and apply to affected areas.
The acetic acid in the vinegar will treat a wide range of garden pests but it requires contact. If you have whitefly eggs be sure to spray under the leaves. Furthermore, white vinegar has a strong odor which has been reported to repel ants and other scent driven pests.
‘If you are wanting to treat houseplants with a vinegar spray, try adding a few drops of essential oil or some slices of lemon peel or rosemary sprigs to help temper the vinegar smell,’ advises Period Living editor Melanie Griffiths.
4. Garlic spray
You may have heard that onions and garlic make good companion plants as the scent of their foliage helps to repel aphids, slugs and carrot fly. This spray takes it to the next level.
‘Puree two garlic bulbs with one tablespoon of vegetable oil, let it sit overnight, strain, add one teaspoon of mild liquid soap and four cups of water to fill the spray container,’ recommends Leigh Clapp.
Store this mixture in the fridge until needed. In the evening, spray both sides of the leaves with the spray and then reapply every few days when your plants are suffering with infestation. Alternatively, use every one to two weeks as a dig up.
If you want to be even more sustainable, why not learn how to grow garlic so that you can have an endless supply of garlic spray – plus extra cloves that you can add to your favorite meals?
5. Tomato leaf spray
If you’ve ever tried growing tomatoes, you will be familiar with the characteristic scent of their leaves, but did you know that these leaves contain a compound called alkaloid which can be used to create a spray that is toxic to aphids and mites? To make a tomato leaf spray, mix equal quantities of chopped up tomato leaf with water and leave to steep overnight. Let this steep overnight, before straining into a spray bottle and applying to the plant’s leaves.
This is a great way to recycle tomato leaves once you’ve pruned them – you can learn how to prune tomato plants for a maximum yield.
6. Cinnamon Spray
If you’ve ever grown plants in pots, you’ll be familiar with the problem of stray mushrooms. However, this can be easily resolved with a simple cinnamon spray. Mix two teaspoons cinnamon powder into four cups of warm water. Allow this to steep overnight and then strain through a coffee filter and then pour into a spray bottle. Mist the potting soil and plants.
Cinnamon spray is also reported to be an effective treatment to get rid of ants. If you have an ant problem in your pots or want to keep ants away from dining or patio areas, try applying cinnamon oil or powdered cinnamon to create an effective barrier.
What is a natural bug killer for plants?
Vinegar is a really effective natural bug killer for plants. Dilute it 1:1 with water in a spray bottle and spray it over and under the leaves of affected plants. You can also use it around the house to detect bugs inside; the vinegary smell will quickly dissipate.
Which homemade bug spray is best for repelling mosquitoes?
The best homemade bug sprays for repelling mosquitoes are those with a strong smell that mosquitoes hate. Other than citronella, which you are probably already familiar with as a mosquito repellent, they include the following essential oils:
- cinnamon bark
- lemon eucalyptus