Anyone with a garden, of any kind, will eventually have to deal with garden pests of some sort. Finding solutions for unwanted pests can be a real challenge, especially if we want to be environmentally friendly and support our local ecosystem at the same time. There are some natural solutions for pesticides however, which can be quite effective in our garden spaces. Neem oil is an interesting example: it has a long history of use by humans but seems to be less well known to contemporary gardeners. So, as we often do, let’s dig in and learn a bit about neem oil and how we can use this organic pesticide in our gardens!
Gardzen Executive Summary:
· Neem oil is a product of the neem tree, Azadirachta indica. The English name “neem” is derived from the Hindi name nim, which in turn comes from the Sanskrit nimba.
· As the origin of the name suggests, the neem tree is native to South and Southeast Asia. Since then it’s been widely introduced to tropical regions around the world.
· Products derived from the neem tree have been used as pesticides and insect repellents for centuries.
· Neem oil contains a mixture of oils and compounds which work as both pesticides—killing unwanted insects and larvae—and pest repellents, keeping them away from our plants and gardens.
· Neem oil products are widely available now, and are often used by gardeners and farmers who want organic, nature-friendly solutions to their pest issues.
· Proper use of neem oil is important; always use garden products according to the manufacturer’s instructions.
· Neem oil can be toxic to both humans and pets if taken internally. Please store neem oil products safely, use them according to the manufacturer’s instructions, and if accidentally ingested seek emergency medical care.
Azadirachta indica: The Source of Neem Oil
The best place to start is the beginning, and for neem oil that means the neem tree. Azadirachta indica is native to tropical South and Southeast Asia, where it’s been widely used by humans for a long time. It’s an impressive tree, capable of growing quite large with lush green foliage and beautiful red-brown bark that tends to form a grid-like pattern as it grows. The fruit it produces develop from little white or yellow flowers that grow in clusters that are, frankly, beautiful to see in season.
These trees serve many purposes both in their own ecosystems and under human cultivation. As a large drought-tolerant tree with a large and deep root structure, Azadirachta indica is now used to prevent or reverse desertification and erosion. The young leaves and shoots are prepared as food in a variety of cuisines across its native region. And—most importantly for our discussion—its dried leaves have been used in homes, shops, and food storage in India as a way of keeping bugs and pests away. Apparently it’s not uncommon to see a few dried neem leaves in a bag of rice or inside of a kitchen cupboard in order to repel unwanted guests.
This was the first use we know of for neem as pest control for homes and gardens. It opened the door for further research that eventually resulted in the creation of neem oil. Speaking of which . . .
Using Neem Oil as an Organic Pesticide
We won’t go into the chemistry behind how neem oil works as a pesticide and pest repellent, but you can read more about that here if you’d like. We’re more concerned with how best to use neem oil in our own gardens as a safe and organic pesticide. Our friends at the University of Florida Extension have a great guide for that, so we’ll summarize and then expand upon based on our own experiences.
It’s best to start with a high-quality neem oil product. We won’t make a specific recommendation here, but spend a little time on product research and talk to other gardeners in your area or you local cooperative extension for specifics. Neem oil should never be applied without being diluted in water; raw undiluted neem oil is toxic to humans and animals and rough on plants. Diluted neem oil shouldn’t be consumed by either people or animals, so please be careful there.
So neem oil needs to be diluted; 1-2 teaspoons of oil per quart of water is generally good. The mixture should also contain a few drops of dish soap as an emulsifier to help the oil and water combine. Any dish soap will do and they’re all plant safe in the US and Canada when diluted to this degree. Neem oil can be applied with a spray bottle or a hand-held pressure sprayer depending on what best suits your needs. We find that it’s best to apply this neem oil mixture either first thing in the morning or in the evening on days when rain is not expected; the goal is to have the diluted oil dry on the plant and provide a protective barrier. Spray both the stems and the tops and undersides of leaves.
Neem is safe for beneficial insects and pollinators, but we do prefer to avoid spraying our flowers and to keep spraying to a minimum when the plant is in need of pollination. We also like to reapply once a month or so---or even more often if the bug situation is out of control! Neem oil works as both an insecticide/pesticide and as a way of killing off larvae and eggs directly, so regular application helps toward that end. There’s no need to overdo it, however, so follow manufacturer’s directions and use your judgment.
Also: wear an easily washable outer layer and gloves while applying neem oil. When diluted it’s not harmful to human skin but the smell is distinct and some people just don’t like it. Since it tends to linger, avoiding getting it on us is a good approach.
Natural Pesticides for Healthy Gardens
Even when we’re using pesticides like neem oil, we need to spend time with our plants. Regular inspection not only helps us notice and address problems promptly, but it’s one of the joys of gardening and a way of connecting with the garden space we’ve created. We should also remember that insects, birds, animals, and even pests are part of the process and working with nature is one of the goals of a healthy garden. We hope this helps you find some solutions for your own garden spaces and that we’ve all learned a bit more about neem oil and its many uses!
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