One of the most common reasons for growing cannabis plants indoors is for better control of the growing environment. However, just because your grow is secure from the elements, it doesn't mean that disease and pests will not find their way to your plants. In fact, many cultivators are left frustrated as their plants growing indoors are attacked by the aforementioned irritants, even when they think the room is totally secure. So, how can you prevent these pesky problems from destroying your indoor grow? These five tips should help your plants thrive in their indoor environment.
Ditch The Debris
While some websites will tell you that using mulch is a good way to protect and insulate your soil, it can actually have a negative effect. Insects and fungi enjoy hiding in dark corners, under decaying leaves or mulch. Do not use mulch in a high humidity grow! Unless you are 100% sure that the mulch that you are using contains a healthy ratio of beneficial microbes vs pathogenic, it might be best to avoid giving the mold a guaranteed hiding/starting place.
The most common bud rot disease is caused by Botrytis. It is paramount that in high humidity conditions, you do not leave any dead plant material around, as this is the propagation site for Botrytis. Without a starting point on dead plant matter, the disease generally cannot get hold of healthy tissue.
Pro tip: Remember, all fan leaves have a natural excision point at the base of the stem. The plant achieves this through programmed cell death to help the leaf fall off naturally – this is often where Botrytis starts.
Keep 'Em Clean
Clean everything - an obvious but often overlooked tip to ensure that disease and pests keep away from your indoor grow. Sanitary precautions should be taken every time you enter your grow room. Wearing clean clothes or having a grow room coverall/suit and keeping your tools clean and disinfected, should keep your grow room sanitary. Rubbing alcohol (Isopropanol) is a good way to sanitise tools and surfaces, and thorough scrubbing with soap and hot water prior, or instead, will help keep microbe counts low. And of course, if you insist on touching the plants, wash your hands first! Even better - avoid touching them altogether! During flowering, you should try to resist the temptation to touch the buds.
Pro tip: Cleaning and disinfecting are not the same thing. Clean and then disinfect, this again seems obvious, but don’t try to disinfect on uncleaned surfaces/areas, as the disinfectant often cannot penetrate through the dirt and grime! Clean first, then disinfect.
Pests – Attract, Distract, And Consume!
Insects come in all shapes and sizes, and this is true of those that infest cannabis, too. Typically, the best strategy is to avoid infestation altogether. However, if your grow already has pests, the best three ways to deal are as follows:
- Attract – Use yellow sticky traps, pheromone and sugar traps. These attract and trap insects of all kinds and they are commercially available from multiple sources. This will reduce the count significantly.
- Distract – Often the pests that find their way to the grow room have no other plants to infest. Cannabis is not the best host for most insects, but if they have no other option, they will attack. The best thing to do is give them another option, a more appealing option! Cover crops and companion plants are great at attracting insects away from the cannabis. Depending on the pests in your local area, you are sure to find some usual plants or flowers that aid in distracting the insects away from your cannabis plants.
- Consume – The use of predatory insects in cannabis grow rooms is as old as cannabis grow rooms themself! These predatory insects are often quite specific and there is not a one stop shop for all insects. Getting the right species for the infestation can be challenging, but once found, it is a fairly easy way to eradicate the problem.
Pro-tip: Identifying the insects in the grow room is vital to determine the treatment you can use. If possible, get into a growing group/cohort with other local growers and help each other identify and eradicate these problem pests. For this, local knowledge is often best.
Buy Pest And Disease-Resistant Strains
Times have changed in the cannabis industry. You can now purchase thousands of varieties of cannabis in seed form, and thanks to selective breeding, there are a number of strains that can claim to be "mold resistant" or "disease resistant". While this cannot always be guaranteed, each seed will have a different level of tolerance to the disease. Finding and purchasing these seeds will likely lead to a hassle-free grow so take a look online and grab those "Resistant Strains". If you have a very bad mold issue, performing a small-scale phenohunt from the resistant line to find the most resistant within that population for your environment could save you a lot of hassle
Pro tip: Much like each plant can have a different degree of resistance or tolerance to a disease, the disease itself can have different varieties in different regions, specific to that area. This means phenohunting for the more tolerant strains is a must for the serious growers, the time and dedication put into the hunt will result in a much more successful harvest down the subsequent grow cycles.
Ventilate And Circulate
Most experienced cultivators understand the value of a grow room with a proper air circulation setup. This helps your plants in a number of ways, not least through the prevention of fungi/spore landing sites. Open-air bud structure and/or good ventilation also keeps the humidity around the plant down. A dehumidifier is paramount and should be controlled by a humidistat for tight regulation of the environment. This keeps humidity levels low, and unfavourable for mold. Mold thrives in humid conditions, so by investing in good equipment you will save money in the long run.
Pro tip: To make sure you don’t overdo it, have a humidifier and dehumidifier ideally on one controller, a humidistat. This will prevent damaging the plants through overdrying of the air, as most environments fluctuate outwith the target humidity. Note also that a dehumidifier will provide some heat into the room which can further antagonise the humidity situation. If you are all in, get a heater and cooler (air con) on a thermostat controller too, thus creating and controlling the environment fully – leading to less chance anything unwanted takes hold in the grow room.
As in most cases, prevention is better than cure - manage the environment and you manage the biotic threat more easily. In cases where you cannot use equipment to control the grow room, consider all the above points and use your problem-solving skills to ‘hack’ your way to a solution.
