Pest Problems

How to Use Neem Oil to Protect Plants from Garden Pests

Natural and effective, neem oil can kill garden insects on plants. Neem oil is a natural vegetable oil that is acquired from the seeds of nim trees. It contains two important elements which serve gardeners pretty well. One of them is Azadirachtin, which is used in many store-bought pesticides.

Azadirachtin is toxic to insects, but it is biodegradable and not a threat to mammals. It affects over 200 different species of insects, acting as a growth disruptor. It stops the development of pests and sterilizes adults, so they won’t be able to lay more eggs.

Another valuable element making the neem oil spray so praised amongst gardeners is Nimbin. This compound is highly antifungal, which could be used as a treatment against parasitic fungi like powdery mildew on plants. Due to its waxy properties, the oil can easily cover and suffocate pest eggs, making it difficult to find a better solution than neem oil insecticide. But where to buy neem oil insecticide in the UK?

Table of Contents:

You will find this useful if:

  • You are a beginner gardener, and you are looking for organic insecticide spray;
  • There are fungi on your plants, and you want to prepare neem oil spray;
  • You are dealing with an insect infestation in your garden;

How to make Neem oil spray for plants

When shopping for neem oil, make sure you are buying a cold-pressed product which still has Azadirachtin in it. Some of the products out on the market don’t contain Azadirachtin, so you can just use olive oil with the same success. What is the ratio of neem oil to the water?

Needed items:

  • Neem oil (with Azadirachtin) – 2 tablespoons;
  • Soap – 1 tablespoon;
  • Water – 2 litres;
  • Mixing container (transparent);
  • Garden sprayer – 2L (or bigger, but you should increase the dose).
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How to mix neem oil for plants

Now that you have everything you need to make your neem oil spray, we can explain how to properly mix it.


  1. Add two tablespoons of neem oil to your water.
  2. Add a tablespoon of soap. (use soap with no additives for better results)
  3. Mix the substance and pay attention to how quickly the oil rises to the top of the container.
  4. Add some more soap if the oil doesn’t start forming a layer at the top of the container within a minute.

Neem oil is hydrophobic, which means it will need the help of a surfactant to dissolve in water. In our case, that would be the soap.

How to use Neem oil spray on plants

Give your sprayer a good shake before using your product. Spray on a small area and wait for at least 12 hours. If there is no damage to the leaves, you can proceed with treating your plants.

Spray from top to bottom, and don’t forget to coat the leaves underside. The good thing is that, unlike homemade pepper spray, this neem oil solution is not toxic to pollinators. Only insects that chew on your plants and their eggs will be affected.

Always test-spray a small area before coating every plant. And as with other plant pesticides, it is best to apply neem oil pesticide early in the morning or in the evening when the temperatures are low.

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When should you use a neem oil spray?

Thanks to its flawless insecticidal properties, neem oil spray is effective against a large number of garden pests.

Pests you can treat with neem oil pesticide:

  • Whiteflies;
  • Green flies;
  • Aphids;
  • Locusts;
  • Scale;
  • Spider mites;
  • Mealybugs;
  • And others.

Thanks to its fungicidal properties, neem oil spray is effective against:

  • Rust;
  • Black spot;
  • Mildew;
  • Leaf spot;
  • Scab;
  • Anthracnose;
  • Blight;
  • and botrytis.

Note that homemade pest control solutions may be effective in treating your plants; however, when it comes to home infestations, it is best to contact a professional pest controller. Some garden infestations can grow inside your home. Treating such infestations with DIY pesticides may give the critters enough time to make nests and reproduce.

What plants NOT to use neem oil on?

Herbs such as basil, caraway, cilantro, dill, marjoram, oregano, parsley, or thyme should not be treated with neem oil. Neem oil can burn foliage on plants with delicate or wispy leaves, such as arugula, lettuce, peas, and spinach.

Rely on tested professional pest control methods for your home!

We can inspect your home for pests and provide the right solution!

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  • Neem oil plant spray is effective against fungi as well;
  • Be careful how much soap you add to the mixture;
  • Always test-spray an area before treating your plants;


Have you ever tried neem oil sprays for any purpose? Was it effective? Share your experience with our reader in the comment section!

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