5 All-natural ways to keep pests away from your outdoor cannabis plants

Published Jun 19, 2019 12:08 p.m. ET
iStock / Stevan Ovicigor

People have been growing marijuana plants outside for thousands of years out of necessity, and in that time, growers learned a great deal about what it takes to keep a crop alive through thick and thin. The most frustrating problem that many people have when they start to experiment with how to grow bigger buds outdoors is the pests that attack and are challenging to manage and or control. Indoors, it’s easy, to begin with, a perfectly sterile environment while keeping any possible contaminants away, but growing marijuana outdoors is free for all, and without a few precautions in place, you are likely to lose a significant portion of your crop.

While we humans don’t often eat cannabis in its raw form, there are many creatures in nature that love to feast on the fresh growth of these hardy little plants. In no time one bug can turn into millions, and the damage that is caused can be difficult to come back from. There are, of course, plenty of chemical products available for purchase that can work quite effectively, but there is no guarantee as to their safety. Since this is a crop you will be consuming, you might want to avoid those types of alternatives whenever possible.

What is there to use instead? Well, when it comes to successfully growing any type of crop outdoors, including cannabis, it all boils down to providing the best environment possible given the situation. It might not seem like you have a whole lot of control in such a vast open space, but the truth is there are quite a few things that you can do which will improve your chances of growing marijuana successfully without using harsh chemicals that might be hazardous to your health.  Here are 5 incredibly useful tips for keeping pests away from your outdoor cannabis plants.

1. Sterilized soil

Most people don’t realize that cleaning the ground in your outdoor garden is possible, and so they plant their seedlings directly into sterilized dirt. The problem with this is that it’s quite often full of contaminants as well as the eggs of some of the most ferocious and common cannabis plant enemies. You should always sterilize as much soil as possible from the top foot of the garden that you plant to use for growing marijuana. To purify the soil, all you will need is large baking pans and an oven. Scoop the soil onto the pan and bake it in an oven at 180F for 45 minutes. Once this is complete, mix 2 tablespoons of peroxide (3%) with every gallon of soil. Once these steps are finished, you will be left with entire fertile and sterilized soil, which is the perfect base for growing marijuana.

2. Build or buy an enclosure

Building or purchasing some type of enclosure can help to ward off some predators, but how many will depend on the kid you choose. Loose netting can be used to ward off larger pests, but the most effective are either mostly or entirely enclosed. This allows for a greenhouse style effect that is merely uncomfortable for many marijuana plant enemies. Learning how to store weed after harvesting can be incredibly useful as well.

3. Natural predators

The cycle of nature is harsh, and almost every predator has another species which will eat and or attack it. The same is true for pesky invaders of your cannabis garden, which is why encouraging the presence of some of these protectors might be vital to keeping your growing marijuana plants alive. One of the easiest to attract is birds, since a small birdhouse, feeder, and a tree is all it takes for a whole family to move in. The key is to wait until after your cannabis plants have reached a stable level of maturity before making this introduction, since birds are naturally drawn to seeds, and will eat them. Another incredibly useful natural predator to marijuana pests is ladybugs, which can be ordered for a reasonable price and released into your garden for the summer. Though many of them will leave, while they remain, they do an excellent job as security guards for your growing crop.

4. Companion plants

Cannabis is notoriously resilient to many different bug species thanks to its high THC content which acts as a natural bug repellant, but unfortunately, it isn’t strong enough to ward off all predators. What you can do to naturally enhance this ability, is to utilize companion plants which will emit their concoction of pest deterring oils. Some of the most effective companion plants for growing marijuana are marigolds, geraniums, onions, basil, garlic, beans, peppers, and mint. Use any of these species by planting them staggered throughout your crop, to provide an even level of protection for all your cannabis plants.

5. Organic repellents


For those who want to take extra precautions, there are ways to create natural barriers between predators and your growing marijuana plants using homemade combinations of various ingredients. Though some store-bought repellants claim to be organic, you will be consuming these plants, so it is always safest to make your insecticides yourself. This way, you know exactly what goes into it and leaves little to no concern for other animals or people who might come into contact with it. Here are five natural insecticide options to choose from.

1. Diatomaceous Earth
This one is a powdery substance that can be purchased in bulk and sprinkled around the soil of the plants to keep predators away. The only problem with it is that it can be hazardous to breathe in, so if you have pets or kids playing in the gardens, it might not be the ideal choice.

2. Neem oil
Neem oil is an all-natural solution that helps to ward off bugs, and it makes the surrounding area inhabitable for those who try. It can be applied directly to the leaves and soil around your growing marijuana plants. It comes with the bonus of acting as an anti-fungus, which helps to protect against lethal infections.

Combine the following ingredients inside of a water mister bottle.

  • 1 teaspoon of neem oil
  • 1 teaspoon of liquid soap
  • 1 quart of unchlorinated water

3. Chili insecticide spray
Chili is a deterrent, but will not kill most pests on contact, so this method should not be used to treat an active infestation. You should, however, use gloves and eye protection while applying this spray, as it will burn if it gets into any cuts or openings.

Mix the following ingredients inside of a water mister bottle.

  • 1 tablespoon of chili powder
  • 1 teaspoon of mild liquid soap
  • 1 quart of water

4. Garlic insecticide spray
Garlic is a gentle deterrent, but will not kill most predators on contact, so this method should not be used to treat an active infestation. It also won’t burn or harm your skin, so there is absolutely no need for extra protection or concern during the application of this homemade insecticide spray. It can be applied to the soil, or directly to the plant leaves.

Combine the following ingredients inside of a water mister bottle.

  • 2 pureed garlic bulbs
  • ½ cup of vegetable oil
  • 1 teaspoon of mild soap
  • 1 quart of water

5. Oil insecticide spray
This spray is often used as both a deterrent and a treatment of infestations in growing marijuana plants. It is entirely safe to use, non-toxic and lingers for quite a while meaning much less frequent application is needed. It can be applied directly to the leaves or the surrounding soil.

Mix the following ingredients inside of a water mister bottle.

  • 1 teaspoon of mild liquid soap
  • 4 teaspoons of vegetable oil
  • 1 quart of water
Complete guide to common cannabis pests and how to treat them


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