Just because an insecticide is natural or organic does not mean a gardener will not need to take safety precautions. Always make sure to follow the manufacturer’s application instructions and research the toxicity of each substance before use. Cannabis growers should avoid using pesticides during the flowering/ripening stage of growth, whether they are organic or not.
Nematodes are tiny insects commonly found on the soil. Predatory nematodes are a great beneficial insect for dealing with any pest insect that spends a portion of its life cycle (eggs or larvae) in the soil. Predatory nematodes feed exclusively on pest insects and can help disrupt a pest insect’s life cycle. Predatory nematodes combined with an organic insecticide or other beneficial insect is the best way to attack a pest insect infestation during any of its life stages and promptly eradicate the problem.
Pyrethrins are a natural derivative from chrysanthemums. This organic compound has been used in horticulture for many years due to its low toxicity to humans and animals. Pyrethrins are extremely toxic to insects and can be used to eradicate a wide variety of pest insects. The concentration of pyrethrins can vary greatly from product to product so following the manufacturer’s guidelines is extremely important.
Most cannabis users do not eat the product, but rather inhale it through combustion. This is just one of the reasons why cannabis growers should always look to natural or organic pesticides as the first line of defense against pest insects. These substances are safer to consume, especially when inhaled.
It is for cannabis growers to research their options. The Pesticide Action Network has information on more than 6,500 pesticides, all of which can be viewed and reviewed on their website: pesticideinfo.org.
Pure castile soap and products sold as insecticidal soap are great organic treatments for soft-bodied pest insects. Insecticidal soap damages the insect’s outer membrane, which leads to dehydration and paralysis. Insecticidal soaps can also be used as an emulsifier and mixed with other organic pesticides. This helps keep the organic pesticide’s active ingredients on the leaf’s surface for longer.
There are a wide variety of chemical treatments available that will quickly knock down a pest insect population. Lee Lyzit helps you avoid the toxic ones.
Pest prevention is also essential for outdoor plants
We’ll take a look now at the most commonly used natural products to prevent plant pests (we’ll also see some chemical compounds used for this purpose). Note that there is a myriad of products on the market and homemade recipes for pest management, we’ll just list some of the most popular, effective and easy to find ones. Also, keep in mind that a wetting agent greatly improves the properties of some of these products, as well as using RO water. Furthermore, some of them may degrade with light, so they must be used during periods of low light intensity.
If your plants look healthy, with no signs of pests or nutrient imbalances, you must make sure that they’ll stay healthy until harvest time. If you already know which are the most common pests in your area, you only have to used the suitable product to prevent them. The following is an example of a prevention plant for the most usually found pests in cannabis. Actually, most experienced growers follow a similar plan throughout the year whether they grow indoors or outdoors:
Bees produce propolis to seal their hives (Image: Flickr)
- After each transplant, or every few weeks in case of mother plants, use trichoderma to reinforce the rot system of your plants
- Use some wide spectrum insecticide (neem , potassium soap or any of the mentioned in this article) once per week
- Spray your plants with water once every two weeks
- A couple of weeks prior to bloom, spray Bacillus Thuringiensis (if growing outside, use BT once per week during July and until you see the formation of the first buds
- Use horsetail one week before the start of the flowering period
Spider mites are one of the most dangerous enemies of cannabis plants
- Use a wide spectrum insecticide the first day of bloom
- About 4 days later, spray your plants with propolis
- About 4 days later, use an insecticide again
- About 4 days later, spray your plants with some fungicide
- Location: You must choose the sunniest and most ventilated spot. Do not put your plants too close to each other and keep them away from other plants that may attract pests (rose bushes, for example, are normally infected by aphids and powdery mildew). You can use some plants – mint, rosemary, wormwood, etc – which are natural insect repellents and put them between your cannabis plants. Of course, remove any dead plant material periodically.
- Temperature and humidity: Unlike indoor growing, there is not much one can do against natural climate conditions when growing outside. As we’ve already seen, choosing the correct spot for your pants – sunny and well ventilated – is crucial to keep temperature and RH at optimal levels. If temperatures raise too much, you can use some shade net to cover your plants (some growers build a cage with anti-thrip netting for their plants to keep insects away while decreasing the temperature a bit). Either outside or in greenhouses, proper ventilation is important to avoid moulds (dew formation) and control temperatures.
- Choosing the correct strain to grow outdoors: Besides what we’ve seed about choosing the correct genetics to grow indoors, in most climates and areas outdoor plants must also be resistant to fungal infections like botrytis or powdery mildew, also to specific insects like caterpillars (which in turn normally bring problems with botrytis). Thus, choosing strains resistant to moulds like Fruity Jack or Tropimango is essential to harvest your plants successfully. Fast flowering strains are favourite among outdoor growers for their easy cultivation and early harvest, which avoids the feared autumn rains. As you may know, our Early Maroc is one of the earliest strains on the cannabis seed market, and a true favourite for legions of outdoor farmers!
This leaf shows symptoms of an infection of thrips
Pest prevention and management for cannabis plants At this time of year, when summer and hot temperatures are comming, a number of mesures should be take in order to avoid pests in your plants,