Sanitize cannabis plants.
Sanitizing is the most critical action you should take right away to help your plants recover and prevent problems in the first place. When you sanitize, you prevent pests and diseases from decimating the entire plant and spreading to your other plants.
Keep your growing area and yourself clean and neat. Don’t leave plant debris lying around. Wash your hands frequently, and launder your clothing after working with your plants. Keep your shoes or boots clean. Wear clean clothes every time you enter your growing area. Aphids, spider mites, and mold spores hitchhike on your clothing, skin, and in the soil on your shoes, and you carry them wherever you go. For indoor commercial growers, we recommend that you wear polyethylene suits and face masks, booties, and gloves in your grow rooms. Always don this clean protective gear before entering the room.
Sterilize your tools. Pruning shears, knives, scissors, or any tool used to cut sick plants carry pathogens that will infect the next healthy plant on which you use that tool. Unfortunately, infections can be symptomless, so sometimes, you don’t know a plant is sick. Tools used on one plant should be sterilized before they are used on another.
Several sterilization methods work well:
• Use a blow torch to heat any metal tool used to cut plants. The heat sterilizes the blades quickly. You don’t have to get them red hot and cause the metal to lose its temper (its hardness and ability to hold an edge)—heat the tool to the point at which it’s too hot to touch. Let the blades cool down before using them again. Use two pruners: While one is cooling, prune with the other. Alternate back and forth, heating and cooling. Orchid growers commonly use this system to protect their plants from viral infections.
• Dip your tools in a 10-per cent solution of household bleach (one part bleach to nine parts water). Be aware, however, that
Bleach can corrode metal.
• Boil your tools for twenty minutes, or heat them in a pressure cooker at 15 pounds of pressure for fifteen minutes.
• Use rubbing alcohol and soap, and water to clean tools. This method is effective against pests such as insects and mites but ineffective against viruses.
Sanitize your plants. Getting rid of infested or infected plant parts or even whole plants prevents the spread of pests and diseases. At the first signs of infection by a pathogen or pest, cut off any parts of the infected plant and immediately remove the debris from your growing area. For example, the mold you see is busy manufacturing millions of spores that float through the air and cause new infections in healthy tissues.
Removing a moldy leaf reduces the inoculum load (the number of spores in the air) and the potential incidence of disease. Similarly, the adult pest you see is busy laying eggs you probably don’t see, so removing infested leaves from your plants helps to control insect populations. However, don’t be so enthusiastic about this that you defoliate your plant. Leaves are vital and provide food that plants need through photosynthesis. If the infection has gotten away from you and is rampant, select an appropriate organic remedy rather than pulling all the leaves off a plant.
Note that for viruses, root rot fungi, and root nematodes, you must pull up or remove the entire plant and discard it.
Sanitize in cannabis growing season.
Sanitize at the end of each growing season. If your plants grow outdoors, sanitize plots after harvest by removing all of the plants, roots and all, and discarding them. Dig them up, bag them, and put them in the trash, or burn the residue if it is safe and legal. Do not compost any diseased material; it can come back to haunt you. Indoor growers can sanitize the indoor growing area by washing down the rooms and all tools and equipment with warm, soapy water.
Before you start a new crop, be sure that residue (stems, roots, and dead leaves) from the last crop is disposed of properly. Many pests and pathogens survive in this plant material and will infect your new, healthy plants immediately. In addition, do not put new, healthy marijuana plants into potting media that supported a previous crop of cannabis. You can use this media for other plants, such as flowers and herbs, but never reuse it for marijuana.