What Plants Not to Use Neem Oil On? 15 Exceptions That’s Best to Know

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what plants not to use neem oil on

Neem oil is a great plant-based pest control solution, and you might have heard it many times. But some plants shouldn’t use neem oil.

Plants are living beings, so they can get sick from the use of solutions not suitable for them. They also need to grow and thrive, and when you use too much pesticide, it can interrupt this process, causing damage to the plant itself.

This article will share what plants not to use neem oil on and what’s behind this solution that makes it dangerous for some plants.

What is neem oil?

Neem oil is a well-known natural insecticide and fungicide that can be used as a treatment for various plant diseases. It’s created from the seeds of the neem tree or also known as Azadirachta indica, which grows in India and parts of Southeast Asia.

The seeds are ground into a powder and then mixed with water. The mixture will give you a yellow-to-brown color, sulfur or garlic smell, and a bitter taste.

Believe it or not, some people use neem oil topically on their skin when they’re trying to treat acne or other skin problems that may be caused by bacteria or fungi. Some people even use it as an ingredient in homemade hair removal waxes or shampoos.

Neem oil is one of the safest ways to control pests, but not for all plants.

Why do we use neem oil on plants?

Neem oil is a versatile plant health product used on many plants. It has a number of uses, including the following.

  • A natural insecticide that kills off insects and controls pests like aphids and thrips. It can be used on fruits, vegetables, flowers, and other types of plants.
  • Helps to repel bugs by increasing the pH levels in the soil, making it less acidic and even repelling some types of weeds.
  • Helps to build up plant immunity as it fights off harmful bacteria and viruses that could potentially harm your plants.
  • Attract birds who eat insects and help keep garden pests away.

How does neem oil work on plants?

Neem oil functions by covering the foliage of the plant. The thin layer of oil dries within 1 to 2 hours. So, insects or pests present in the plant will ingest the chemical compounds of neem oil, especially azadirachtin (the most active component).

Azadirachtin is the component that can interfere with the pests’ hormone system. This will affect the pests in laying and growing eggs, which can stop their reproduction.

Neem oil also has other components other than azadirachtin. These remaining components aid in killing pests by hindering them from feeding themselves.

What plants not to use neem oil on?

In general, you can spray or apply neem oil to any plant. But you need to understand that it’s at your own risk. So, what plants not to use neem oil on?

  • Arugula
  • Basil
  • Caraway
  • Chives
  • Cilantro
  • Dill
  • Lettuce
  • Marjoram
  • Oregano
  • Parsley
  • Pea
  • Rue
  • Sage
  • Spinach
  • Thyme

If you notice, most neem oil-sensitive crops are herbs. But why does neem oil harmful to these plants?

The main reason is that neem oil is a powerful organic pesticide to the point that it can burn plants with delicate leaves like herbs. This is especially true if you apply neem oil on a hot sunny day when the temperature is high.

If there are neem-sensitive plants, there are also crops that don’t really need neem oil. These crops include:

  • Garlic
  • Lavender
  • Leeks
  • Onion
  • Scallion
  • Shallot

How to use neem oil on plants properly?

Sometimes, neem oil can also be harmful to humans. So, you must know how to dilute neem oil for plant use. Here are the steps you can follow.

  • Prepare your materials, such as a garden sprayer, a bottle of neem oil, and organic liquid soap.
  • Fill your garden sprayer with sufficient water.
  • Mix two tablespoons of neem oil per one gallon of water. So, if you have 2 gallons of water, mix it with four tablespoons of neem oil.
  • Then, mix one tablespoon of organic liquid soap per one gallon of water. 
  • Shake your mixture well and pressurize your garden sprayer.
  • Always spray neem oil before the sun sets and not during the day to avoid burning your plants.

Can neem oil affect humans?

Aside from knowing what plants not to use neem oil on, you might also wonder whether it can affect you. Here’s the thing, you can get exposed to the components found in neem oil through inhalation and skin contact. This is why you must wear protective wears like gloves, long sleeves, and a face mask when applying neem oil to your plants.

Here are some potential effects of neem oil on humans.

  • Skin and eye irritation
  • Stomach irritation if swallowed.

It also has some effects on animals like cats, and it includes the following.

  • Feeling sluggish
  • Too much salivation
  • Trembling
  • Convulsions
  • Impaired movement
  • Twitching

Is it ideal to use neem oil before the harvest?

It’s not enough to ask what plants not to use neem oil on, you also need to know how to properly harvest a plant with neem oil on it. Here are some things to remember when using neem oil before your harvest.

Spray neem oil as early as possible.

It’s important to check your plants regularly, especially when it’s nearing the harvest. This is because you need to see if there are infestations. If there is, you need to spray neem oil as quickly as possible because it takes 4 to 5 days to work.

If the timing isn’t perfect, like some are ready for harvest, then you need to pick those crops before treating the infested ones.

You can harvest 5 to 7 days after applying neem oil.

If you have crops that you spayed neem oil on, you can check it after 5 to 7 days and harvest it. At this rate, you’re sure that neem oils have already done their work.

Don’t harvest after spraying, and do not spray on sunny days.

Harvesting right after your spray neem oil won’t do any good for your plants and you. First, it doesn’t affect the infestation of your plant and will only harm you and the people who’ll be in contact with the plant with neem oil.

Be wise when using neem oil!

So there you have the answer regarding the question, What plants not to use neem oil on? There are a lot of plants that neem oil can be used on, but it’s important to keep in mind that not all plants are created equal. Neem oil is great for plants susceptible to pests and disease, but if you’re looking to do more than just kill insects, you may need something stronger or different.

If you’re just starting out with neem oil, don’t use it on everything! Start with your garden’s most common plant types and get a feel for how it works before trying something new.

You can save this post as a reference to save your plants from getting damaged or burned by neem oil.

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