Neem oil is a natural remedy for controlling certain pests. It is an organic pest control solution with many other benefits and uses.
Neem oil comes from the seeds of the neem tree (Azadirachta indica), a tropical evergreen tree [1].
It reduces insect feeding and disrupts insect hormone systems, making it difficult for them to lay eggs and grow.
Neem oil is particularly effective against insects that chew on leaves. Its smell also naturally repels many pests in the home and garden.
The Benefits of Using Neem Oil on Plants
Neem oil is a natural fungicide and insecticide, and it is used in a wide variety of garden and home products.
It can kill insects and fungi. So, it controls many pests and plant diseases.
Additionally, the deoiled residue (neem cake) from crushed neem kernels is widely used as an organic fertilizer [2].
Below are the main benefits and uses of this remedy in the garden.
1. Treatment of Bacterial and Fungal Disease Issues
Many gardeners use it to treat fungal and bacterial diseases in plants.
Neem oil fights fungi and bacteria. It helps keep your garden clean by reducing mildew, black spots, leaf spots, anthracnose, fire blight, rust, and mold.
Regularly spraying neem oil solution on plants in and around the garden can help control many bacterial and fungal problems.
2. Control Pests
Neem oil can also help control many pests that destroy food crops and other plants.
Neem oil pesticides are often the first choice for organic gardeners. They are effective against many types of destructive bugs and pests and can be applied in several ways.
A spray solution around plants and directly on leaves kills some pests and repels others, reducing the number of garden pests.
Some garden pests that neem oil works against include:
- Caterpillars
- Leaf-footed bugs
- Leafhoppers
- Aphids (greenflies)
- Spider mites
- Lace bugs
- Fungus Gnats
- Leaf miners
- Some beetles
- Grubs
- Spotted lanternflies
- Tarnished plant bug
- Mealybugs
- Whiteflies
- Squash bugs
- Grasshoppers
- Locusts
- Worms
Moderate neem oil applications can benefit the soil. They reduce harmful nematodes but leave earthworms unharmed.
3. Natural Fertilizer
Because it works as a systemic insecticide when applied to the soil, neem oil acts as a fertilizer, increasing plant immunity.
Why is this so? It reduces nitrogen release, so plants can take up more nitrogen from the soil, improving soil quality.
Neem oil also makes a great foliar fertilizer, and neem cakes are a great NPK fertilizer for your garden [3].
4. Glossy Foliage
When used correctly, neem oil sprays leave foliage healthy and looking glossy.
Neem oil can be used to clean the leaves of indoor plants, especially in enclosed spaces like greenhouses.
You can dampen a rag and wipe the top and bottom of each leaf with your DIY solution (recipe below).
How to Use Neem Oil in the Garden
Be careful when using, as some irritation may occur on sensitive skin and in the eyes.
Make a homemade neem oil spray by combining 5 ml of neem oil, 2 ml of organic liquid soap, and 1 liter of water. Shake well and spray both sides of the plant leaves.
Alternatively, purchase a neem oil concentrate online or at your local garden center. Use it according to the label’s instructions.
Apply the solution every three weeks. However, if there is an infestation, apply it once a week to keep pests under control.
However, do not use neem oil in hot weather, as it will likely cause foliage burns. It can also damage newly transplanted or stressed plants.
Spraying in the spring and other suitable times throughout the year can target the eggs and larvae of various pests.
To wipe down houseplant leaves, mix one teaspoon of neem oil with half a teaspoon of liquid soap in a liter of warm water. Use this solution to wipe down the plant leaves to achieve a glossy shine.
Ingredients
Various ingredients can be found in neem oil.
One popular one is azadirachtin. This component is toxic to some pests, disrupting their molting process.
Other active ingredients include picrin, nimbin, and sialin [4].
What Plants Not to Use Neem Oil On
Generally, neem oil is safe for use on most plants.
However, please do not use it on herbs like thyme, cilantro, oregano, parsley, or dill. These plants are sensitive to neem oil.
It can also cause leaf burns when used on leafy vegetables such as lettuce, spinach, and arugula. Moreover, neem oil can block the pores of ferns’ sensitive leaves.
High doses can burn plant leaves, so read the label carefully, as it lists any restrictions.
How It Affects Beneficial Insects
Neem oil insecticides control bugs and pests that feed by sucking or chewing on plant leaves.
Therefore, if used correctly, it will not affect butterflies and bees because these insects do not eat leaves.
Wasps and ladybugs, which effectively deal with aphids and other small insect pests, are unaffected unless neem oil is sprayed directly on them.
Do not spray on blossoms or flowers that these pollinators might land on. And do not spray helpful insects with it.
Effect on Pets and Animals
Neem oil is safe for cats and dogs when used correctly. Various grooming products for pets contain nourishing neem oil.
Also, experts have tested using neem leaf meal in broiler rations instead of antibiotics [5].
However, some slight toxicity has been shown in fish, so do not use neem oil near ponds or rivers.
Effect on Humans
Studies have shown that neem oil is potentially toxic to children and adults if ingested in large doses [6].
However, for gardening purposes, you can use it throughout the growing season up until the day of harvest. Just be sure to wash your produce correctly.
Where to Buy Neem Oil to Use on Your Plants
Pure neem oil, sprays, and liquid concentrates are sold online, at gardening stores, and at other retail outlets.
Neem cake is also sold as a soil supplement and fertilizer for plants.
Takeaway
As you can see, neem oil benefits the garden in many ways. As a result, it is widely used in many agricultural products.
The benefits of using it on plants are vast, especially for the organic gardener.
I use neem oil for diseases on tomatoes , and keeping moths from laying eggs on my cherries
Thanks for this information. Much appreciated.
Is this safe to spray on a fruit tree after the flowers come out?
It will not harm the flowers but it might harm pollinators.