Morpho-physiological plant quality when biochar and vermicompost are used as growing media replacement in urban horticulture

Peat moss is the most used soilless substrate in the production of container plants in floriculture. Nevertheless, the drainage of peat bogs due to the peat extraction has increased the necessity of seeking products that could replace the peat that is used in plant production. Therefore, a comparative study was conducted to evaluate the effect of a biochar (B) - vermicompost (V) mixture, as a partial substitute for peat-based substrates, on the morpho-physiological characteristics of ornamental plants. Different blends containing B and V were compared to a baseline peat-based substrate (S) as control in the cultivation of two ornamental bedding plant species that are widely used in urban areas: geranium (Pelargonium peltatum) and petunia (Petunia hybrida). Plant growth and physiological parameters were assessed. Results showed that it is possible to grow container plants of these two species with commercial quality, using a peat-based substrate mixed with biochar and/or vermicompost (up to 30% V and 12% B). Plants in these substrates showed a similar or enhanced physiological response to those grown in the control using commercial peat-based substrate.