Neem oil is a commonly used pesticide for garden plants. It is inexpensive and readily available, and is effective against aphids, mites and several types of fungi.
While neem oil is a popular choice of pesticide, it is important to know how to apply it properly to your plants, because spraying too much, or too frequently, can lead to unwanted damage to the plant.
An ideal ratio is one gallon of water to two tablespoons of mild dish soap to two tablespoons of neem oil, which should be enough to get rid of any unwanted pests on your plants.
In this article, we will learn more about the correct mixture of a neem oil plant spray and how to apply it to your plants. So, if you are considering using this substance in your garden and wish to learn more about it, just keep reading.
What is neem oil?
Neem oil is extracted from the seeds of the neem tree, which is native to India. This substance has been used in traditional medicine for centuries, and has gained popularity as a biopesticide because it is non-toxic to humans, unlike most commercially available pesticides. While ready-to-use, premixed neem oil spray can be bought at a store, it is very easy to mix your own spray at home using 100% pure neem oil, and this will also save you some money.
Is neem oil toxic to animals?
No. As mentioned above, neem oil is non-toxic to humans, and the same is true for most animals, including pets and any wildlife that may find its way into your garden.
You are only going to be using a small amount of neem oil in your spray mixture, and this low concentration will not harm you or your pets. Even if you or your pet do ingest a significant amount of neem oil accidentally, it is non-carcinogenic and will have no long-term effects.
Fortunately, neem oil is also non-toxic to beneficial insects such as butterflies, spiders, ladybugs and bees, as long as they are only exposed to it after the plant has been sprayed. Try not to spray the neem oil mixture directly onto these insects.
Do note that exposure to high concentrations of neem oil can be slightly toxic to amphibians and fish, so make sure to keep those pets away while you are handling neem oil.
Is neem oil effective against all kinds of pests?
While neem oil is effective for most commonly observed houseplant pests, it is not a universal pesticide. For example, it cannot get rid of caterpillars that feed on the leaves of plants, and it is also limited regarding the types of fungi it can eradicate.
Neem oil is most effective against insects that have softer exoskeletons, such as white flies, scale insects, mealybugs, spider mites, thrips and aphids. The oil covers the insect’s body and either kills them immediately or disrupts their feeding and reproductive capabilities.
Neem oil contains the compound azadirachtin, and it is this that effectively interferes with insects’ mating, egg-laying, molting and feeding.
How to mix neem oil for plants
- Before making your neem oil spray mixture for your plants, you will need to prepare two tablespoons of mild dish soap, two tablespoons of neem oil, one gallon of warm water, and a container big enough to hold all of those ingredients. You can wear gloves if you would like to, but they are not necessary.
- Pour the water and the dish soap into the container. The dish soap is going to act as the emulsifying agent. Remember that water and oil do not mix, so the soap will help the other two ingredients incorporate better. Mix the water and dish soap thoroughly. This combination by itself is already a good pesticide against insects with soft exoskeletons, but adding neem oil will make it even more effective.
- After mixing the water and dish soap, add the two tablespoons of neem oil little by little while continuously agitating the solution. When all of the oil has been added, take some time to ensure it has been blended well.
- Pour the neem oil mixture into a garden sprayer and apply it to the tops and undersides of all your plants’ leaves. You can wear gloves if you do not want any drops of the oil getting onto your hands. This can be a useful precaution, especially for people who might have an allergic reaction to the oil.
Can I use this spray mixture on all my plants?
No. Neem oil spray can be too harsh for seedlings, because they are so delicate. Wait until the plant is at least two months old before exposing it to neem oil. You might have to reduce the neem oil to one tablespoon for younger plants and only use the two tablespoons in the full recipe for mature plants.
What time of day is best to spray the neem oil mixture?
The ideal time of day to spray your plant with the neem oil mixture is just as the sun is about to set. The first reason is that if you apply the mixture when the sun is still high, the presence of the spray on the leaves can lead to sunburn. Another reason to wait until the late afternoon is that, at this point, the beneficial insects are probably tucked away and will be better protected from being directly hit by the solution. This way, only the pests are significantly affected and the solution will have the entire night to work its magic.
How often should I spray my plants with the neem oil mixture?
You must not spray your plants any more frequently than once a week. There is no lasting effect, but there also does not seem to be any noticeable difference in effectiveness between spraying once a week or spraying more often.
As to how many weeks you should continue applying the neem oil mixture, this is dependent on the situation. Make sure you check the plant every week before you spray it to check whether the application is necessary. If the plant looks completely pest-free, then you are free to discontinue spraying it.
Tips for neem oil use
- Remember not to add too much neem oil to your mixture, as increased concentrations can lead to sunburn.
- Wait until the plant is at least two months old before spraying it with the mixture.
- Make a new batch of neem oil mixture on the day of intended use, because stored, old mixture will have a different consistency and will be difficult to spray. Only prepare a batch big enough for you to finish on the day.
- You can use a hand soap that contains peppermint extract as added insect repellant. Some insects instinctively shy away from the smell of peppermint.
- Neem oil is also effective against some fungi, so you can try using it on your trees – especially those afflicted with powdery mildew.
Conclusion
Neem oil is an inexpensive, readily-available, non-toxic pesticide that can eradicate most soft-skinned pests and some fungi.
While commercially available neem oil sprays are an option, it is cheaper to make your own mixture at home. Mix one gallon of water with two tablespoons of dish soap and two tablespoons of neem oil. Mix the solution thoroughly before transferring it to a sprayer.
Spray the solution once a week for as long as needed. Make sure you spray your plants during the late afternoon so that the leaves do not burn under the hot sun.
Image: istockphoto.com / Ninetechno