I found several aphids on one of my container vegetable plants and wanted to get rid of them. I heard neem oil can work well to get rid of such pests and keep them away. But I also wanted to check if I can spray it on edible plants.
Neem oil is safe to use on edible plants but you need to be careful with the amount you use. A small amount will protect the plants from pests. But an overdose will kill the plants and it’s toxic to humans as well.
You will find neem oil used in some pesticides or you can use it in pure form as well. I’ve researched more details on how to use neem oil and prevent it from becoming toxic.
Is neem oil toxic to humans and pests?
Neem oil contains Azadirachtin which is a chemical that can act as a pesticide to kill insects. This chemical is found in neem seeds and pesticide makers extract it to create a pesticide.
You can also find this chemical in neem oil. So diluting the neem oil with water will give you a potent homemade pesticide.
The small doses of this neem oil are safe to use but larger doses can be toxic to humans.
Pests neem oil can repel
Neem oil can discourage pests like aphids, whiteflies, and mealybugs from invading your plants. You can use the oil to treat the infestation when such pests show up on your plants.
And once you get rid of the pests, you can continue applying the oil to keep the pests away from the plants.
These pests find the smell of the neem oil to be strong and discouraging. That’s the reason they will move away from the plants.
You can also apply the neem oil to keep fungus that causes mold or mildew away from your edible plants.
Pests neem oil can kill
Neem oil is beneficial to kill pests like mites and nematodes. It also stops the life cycle of such insects by preventing reproduction and feeding ability.
It prevents insects from laying eggs and can stunt the growth of some of the pests. While these processes don’t kill the pests, preventing future generations of insects can limit infestation on your edible plants.
Beneficial insects and neem oil
The good thing about neem oil is that it does not indiscriminately kill all kinds of insects. This means beneficial insects like bees, butterflies, or lady beetles are not harmed by it.
As long as these beneficial insects can bear the smell of neem oil, it is harmless to them. They won’t eat your edible plants and so the neem oil won’t affect them.
It’s always good to keep your pets away from the garden. But neem oil is not harmful to your pets even if they manage to consume a little bit.
How to use neem oil on your edible plants
Neem oil is natural and can work well as a pesticide in the garden. But when it comes to spraying neem oil on edible plants, you need to take some precautions.
You need to avoid applying pure neem oil on your plants. It is toxic and will burn your plants.
Many commercial pesticides might have a little neem oil in them. But the concentration is quite low so it won’t harm you or your plants.
You can make a pesticide from neem oil if you use it at three percent concentration. That is sufficient to repel or kill unwanted pests in the garden without affecting the plants, humans, or animals.
Dilute neem oil with water
If you plan to make homemade insecticide, you’ll need pure neem oil such as Harris Neem Oil. This is unrefined and does not contain any additives making it suitable for use in an organic garden.
Grab a large bucket and fill it with a gallon of water. Mix one ounce of neem oil with the water until it dissolves. You can add an ounce of organic dish soap that is free from chemicals.
The dish soap will help the neem oil to stick to the leaves and stay there longer so it can be effective.
If you need more or less, you can adjust the ratios between the water and neem oil. Make sure that you don’t use more than an ounce of oil for every gallon of water.
Spray neem oil on plants
Once you have your mixture and are ready to use it, put it in a spray bottle. Spray a little neem oil on the plant and leave for 24 hours.
Then you can check if the neem oil has caused any damage to the plant. If it has, you need to dilute it more with water and try again.
If there’s no damage to the plant, use the bottle to spray the solution all over the leaves of your plant.
Make sure to spray on the upper and underside of the leaves where pests will make their homes.
If you’re using the solution to get rid of existing pests, you should use it once per week. But if you want to use neem oil to prevent pests, you can use it every one to two weeks.
You can set a schedule in your calendar to remind you when you need to apply the mixture. Either way, you don’t want to use it too often. Otherwise, the leaves might have too much neem oil for you to consume safely.
When should you spray neem oil?
You can spray the neem oil on the plants every couple of weeks to keep the unwanted insects away from them.
When your edible plants are close to harvest, you can reduce the frequency or completely stop using the neem oil.
You should not spray neem oil on the plant if it’s already under stress. This could be due to heavy infestation of pests, overwatering, underwatering, or fungal, viral, bacterial infections.
You need to help the plant get better from the above problems before you can think of using neem oil on it.
What are the different types of neem oil?
Azadirachtin is the active ingredient in neem oil. Once that is extracted, you get hydrophobic neem oil.
Too much Azadirachtin will kill your plants and it is also an irritant that will harm your eyes and skin. Hydrophobic neem oil is free from these problems and is safe for you and the plants.
If you use neem oil with Azadirachtin, you need to be careful how much you use on the plants and how often. Even with a low concentration, you may need to wait longer after the last use before eating your edible plants.
How long does neem oil stay active on the plants?
You should also consider how long neem oil can live on your plants. Its active ingredient has a half-life in soil from a few days to about a month and a half.
When in water, the oil’s half-life ranges from an hour to four days. The half-life on plant leaves is about one to two days.
After those times, half of the neem oil will still be there. It takes five half-lives for less than three percent of the original content to remain.
While you can eat some neem oil safely, you should give as much time as possible between the plant’s last neem oil exposure to when you eat it. Then, you can make sure the concentration is as low as it can be.
If you don’t want to wait that long, you can wash your plants. Make sure to wash the plant thoroughly to get rid of as much of the oil.
Neem oil is an excellent natural pesticide, and you can use it throughout your garden. As long as you keep the concentration low and use it infrequently, you can use it on edible plants. Then, you can enjoy the fruits of your labor while avoiding pests in the process.