Silica Amended Peat Substrate Increases Dry Bud Weight Yield by 28% and Improves CBD Production by 16% in Cannabis (North Carolina State University Findings)


Posted May 8, 2021 


Some 20 years ago I sung the merits of using silica in indoor growing, in the book Integral Hydroponics. In fact, I was perhaps the first grow book author to write about using silica in indoor growing situations.  


Some 20 years later (finally!) there is a study that demonstrates that indeed silica is a beneficial element in cannabis production.


Silicon-Coated Perlite Research Results


In an NCSU study, researchers blended a 70% peat and 30% perlite substrate. To aid irrigation, researchers added a wetting agent to the substrate in addition to dolomitic lime to obtain a substrate pH of 6. The variable was the perlite formulation. One set of plants had uncoated perlite, while the other substrate mixture used a coated perlite mix that included Si and a low level of potassium phosphate. (Si chemically bonds to potassium phosphate for plant delivery.)


Clones of the CBD cultivar ‘BaOx’ were transplanted into the substrates, grown vegetatively over four weeks before inducing flowering with long nights. Researchers measured growth parameters during the experiment and cannabinoid profiles at the end of the study.


Researchers found plants grown in perlite coated with Si had larger diameters. Nutrient uptake was also higher in plants using coated perlite. Nitrogen, phosphorus, potassium, and sulfur concentrations were higher in the plants with the Si perlite blend compared to the uncoated perlite.


There was a 28% increase in the total bud dry weight produced by each plant grown in the coated perlite blend. In addition, the total CBD production per plant was 16% greater with the coated perlite versus uncoated. Based on these trials, the addition of Si improved overall plant performance and yield.



Authors of study. Brian E. Whipker, David Logan, Patrick Veazie, Paul Cockson and W. Garrett Owen (NCSU)


Information originally posted on Cannabis Business Times @

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