Evaluation of the Potential Phytotoxicity of Gro-Bark Feedstocks

Phytotoxins are defined as substances that are poisonous or detrimental to the growth of plants. These substances may result from human activity, as with herbicides, or they may be produced by plants, microorganisms, or by naturally occurring chemical reactions. As Gro-Bark utilizes a number of natural recovered resources for growing media feedstocks, we recently undertook a trial to examine for the potential presence of phytotoxic compounds in our bark and compost to assure our customers that all our materials are phytotoxin free.

Due to the overabundance of potential phytotoxic compounds and the varying rates of sensitivity of different plant species and cultivars, it is practically impossible to conduct a laboratory analysis for the presence of individual substances which may cause phytotoxicity. Therefore, in order to assess whether there are harmful substances in Gro-Bark materials, growth and germination tests were performed.

Overall, the results of this growth and germination tests demonstrate that Gro-Bark’s Blend A, Compost, CPM and Aged Bark are free of any phytotoxic compounds at levels which can cause issues to plant germination, growth rate and root elongation. For the detailed trial report, please click here.

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