Neem oil is a naturally occurring pesticide pressed from the seeds of the Azadirachta indica tree (also known as the neem tree), a tree found primarily in eastern India but also in other Asian countries such as Pakistan, Burma and Bangladesh.

The oil ranges in color from yellow to brown and smells distinctly of a mix of garlic and sulfur. For savvy gardeners looking for a gentle, organic, yet effective method of controlling pests in their garden, neem oil is fast becoming the go-to pesticide.

Neem Oil: A Versatile Substance

For hundreds, if not thousands, of years, neem oil has been used to create pesticides and medicines in India, but its transition into western civilization is still relatively recent. Now, various components of the oil can be found in everything from toothpaste to pet shampoos, cosmetics to soaps and even in some foods and drinks. Neem oil is an incredibly versatile substance, which is one of the reasons it makes a fantastic pesticide.

How Neem Oil Works as a Pesticide

When used as a pesticide, the most active component in neem oil is azadirachtin. For the most part, you won’t notice an immediate drop in your pest population after you start using neem oil, but don’t panic. This is all part of the process. When insects ingest neem-coated foliage, the substance begins to disrupt their hormone system.

For some insects, this results in a loss of appetite while for others it interferes with their reproduction patterns. In either case, this means the insects fail to reproduce and subsequently die out. For insects unlucky enough to sit atop the foliage when neem oil is sprayed on it, the process is much quicker.

The substance smothers their bodies, rendering them unable to breathe. Similarly, insect eggs coated with neem oil will be unable to hatch, preventing any colonies in your garden from growing. The final way neem oil serves as a pesticide is by deterring insects from feeding on them in the first place. As soon as neem oil is applied to your plants, they’ll begin to taste bitter and unappealing to insects, thus they’ll quickly move on to the next piece of foliage.

The Effects of Neem Oil

Neem oil can be used as a pesticide to target dozens of pesky insects—the uncommon ones as well as the common ones. Here’s a quick list of the insects neem oil affects:

  • Ants
  • Snails & slugs
  • Grasshoppers
  • Earwigs
  • Whiteflies
  • Aphids
  • Beetles
  • Moths
  • Worms
  • Loopers
  • Fruit Flies

One of the best things about neem oil is that, unlike many pesticides, it differentiates between the insects we want in our gardens and those we don’t. Growers can use neem oil persistently without having to worry about it affecting earthworms, bees, wasps, ladybugs or other beneficial garden creatures.

Even better, small concentrations of neem oil have no effect on mammals or birds, so your pets and other frequent garden visitors will not be at risk from the substance. In addition to working as a pesticide, neem oil also effectively kills the majority of algae and mosses, and it also kills and prevents most fungal diseases such as rush, mildew, black spot and anthracnose.

Is Neem Oil Safe?

One of the biggest issues surrounding neem oil is whether or not it’s safe to use. The simple answer to that is yes. It’s been used in medicines, as an ingredient in food and in other human-ingested substances for years, so you need not fear about eating crops it has been applied to, or accidentally inhaling it during spraying. It has been reported that some people find neem oil irritating when it comes in contact with the eyes; however, the effects pass within a matter of hours and this can easily be prevented by wearing protective eyewear while applying.

As a precaution, it’s advised you wear protective clothing when working with neem oil, but there is no evidence to support that this is absolutely necessary. The Environmental Protection Agency has done many studies surrounding neem oil and has not set forth any advisories or restrictions concerning the use of the substance.

Fruit trees, herbs and vegetables can be sprayed with neem oil right up until the day they are harvested without posing a safety concern to those who consume them. The substance will not harm your hard-earned harvest in any way and there are no plants neem oil cannot be used on.

Neem oil is completely organic and not harmful to the environment. As previously mentioned, it poses only a minimal threat to mammals and has the added benefit of being completely biodegradable. When exposed to sunlight, neem oil biodegrades in a matter of weeks and has no lasting effects on the environment.

Tips for Using Neem Oil

Like all pesticides, there are certain things you can do to use neem oil more effectively.

  • When storing concentrated neem oil, it is best to keep it in low light conditions at roughly 40°F so it retains its potency for longer.
  • When using concentrated neem oil, only mix up the amount you’re going to need because over time the oil and water will separate.
  • Neem oil comes in various concentrates, so be sure to read the instructions carefully before mixing up a batch or applying it to your plants.
  • You can purchase neem oil as either a concentrate, which you only need to add water to, or as a ready-to-use formula, whichever suits your needs best. The only real downside to the use of neem oil is that its effects can wear off quickly, so in some cases it may need to be re-applied every few days.

If you want a healthy, organic garden that is also pest free, visit your nearest garden center or indoor garden shop and get started with this long-used, versatile substance. Neem oil is indeed an organic gardener’s dream.