PreventingThreats to Cannabis Cuttings

This purpose of this educational material is to identify threats to the cannabis cloning process as well as to provide preventative measures in order to avoid these threats.  This information can be applied to cannabis cuttings rooted in the following containers: propagation trays; aeroponic and hydroponic cloning machines; or containers of stillwater.  

Threats to the Cannabis Cuttings

  1. Viral Pathogens:  Viruses like hemp streak virus and hop latent viroid are commonly spread through mechanical transmission.  That means if you use the same scissors or razor to cut clones from all mother plants without sanitizing thoroughly between plants, any virus can easily spread to all mother plants cut after an infected plant.  

    1. Preventative Measures:  Sanitation procedures are the best defense.  These procedures should at minimum include the following items:

      1. Keep cuttings segregated to trays or cloning machines specific to individual mother plants.  

      2. Do not take clones from plants that are showing signs or suspicion of viral activity.

      3. Prior to cutting clones, prepare a small amount of 10:1 water to bleach solution and store in a narrow plastic container.  Sanitize your cutting device between every plant. Be sure to wipe the bleach solution off with a fresh paper towel.  

      4. Sanitize thoroughly containers used to store and propagate cuttings into clones.  Be sure to scrub and wipe every crevice and corner, inside and out.  


  1. Microbial Pathogens:  Molds such as pythium as well as harmful bacteria are invisible until they aren’t.  Microbes can hide in small crevices and corners of plastic containers. When harmful microbes become a problem for the cuttings, it is difficult for them to recover.

    1. Preventative Measures:  Sanitation procedures are the best defense.  These procedures should at minimum include the following items:

      1. Sanitize thoroughly containers used to store and propagate cuttings into clones.  Be sure to scrub and wipe every crevice and corner, inside and out.  

      2. Prior to taking cuttings mist a sanitizer solution over the trays, tools, and equipment. Sanitizer solutions include:  1% Hydrogen Peroxide solution; 100 ppm Nixall; or 1 tablespoon Bleach to 1 gallon Water. Use a spray bottle that can mist if possible.  

      3. Change the cloning water in the containers no less than every three days.  

      4. Use beneficial microbes in the cloning water such as SLF 100. 

      5. Keep areas around the cloning containers sanitary.  

      6. Use air sanitizing devices such as hepa filtration or UV bulbs.  


  1. Clone Water pH and Temperature:  Clone water solution should have a pH of between 5.2 and 5.4 and be between 78 to 82 degrees fahrenheit.  Sometimes you might find your clone water pH will drift up. After adding an acid to lower the pH of water, some water supplies require two days or more for the acid to complete its reaction with the elements in the water that make the water naturally or artificially alkaline.  Artificially means that some water facilities add pH buffers to municipal water supplies because a low pH causes corrosion of pipes and possibly heavy metal contamination such as lead. If the temperature of the clone water is out of range or if the temperature is not consistent the cuttings may suffer. 

    1. Preventative Measures:  Tempering is the key to success. 

      1. Allow at least one day for the clone water solution to neutralize after adding acid to lower pH.  

      2. Bring the clone water solution up to temperature before introducing the water to the cuttings.  This can be done in the same day waiting period after adding the acid.  

      3. If using heat mats be sure to keep the temperature probe submerged in the water.  Use a separate thermometer to randomly test the temperature of the clone blocks to ensure they are within the temperature range.  

      4. Check the pH and temperature of the clone water at least once daily.


  1. Equipment Failure:  It is a fact of life, all electronic devices will eventually fail.  A thermostat may go on the fritz and either blanche your cuttings like cooked broccoli or leave them cold.   The power may go out and cause timers to be off schedule. The pumps in an aeroponic or hydroponic cloning machine may fail and your cuttings fail from drought.  

    1. Preventative Measures:  Check all systems more than once daily. 

      1. Set a timer on your phone as a reminder to do a quick check on the systems.

      2. Have a back up plan in mind for all equipment in your cloning process.  For example, if a heat mat or thermostat fails, and you don’t have a replacement, consider making the room warmer, or using other devices such as a space heater or heating pad as a temporary solution.  It is important to check the temperature regularly using a probe thermometer.


  1. Pests:  The best environment conditions for rooting clones happens to be the best conditions form many forms of life to thrive.  That means it is easy for a damaging pest to set up home and quickly become an infestation. These pests include fungus gnats, thrips, mites, aphids, and harmful nematodes.  

    1. Preventative Measures:  an ounce of prevention is worth a pound of cure. 

      1. Know your pest threats.  What are common pests to your grow or your region?  Treat in advance by use of natural pesticides or beneficial organisms.  For example, thrips are controlled using cucumeris mites and orius bugs.  Fungus gnats are controlled using beneficial bacteria and nematodes.  

      2. Set up sticky traps to capture identify flying insects.  Flying insects commonly come with larvae that thrive in clone blocks and warm water.  

      3. Do not cut clones from plants known to have pest issues.  If so, then keep those cuttings in their own tray, in their own room away from the healthy stock.  Be sure to apply a method to eradicating the pest prior to cloning. For example, dipping a cutting in a solution of Suffoil X is known to aid in the eradication of thrips.  Another example is dipping a cutting in a solution of Beauveria Bassiana fungus to control root aphids.  

      4. Prepare mother plants with natural pesticides in the days prior to cutting clones.  Be sure to follow label instructions accurately.  

      5. Use a magnifying glass when checking on your clones.  Get a good look at them and take note of any concerns and their locations in the cloning containers.

      6. If pests are discovered, immediately quarantine the cloning containers with the infected cuttings.