Abstract
The inability of certain economically useful flowering plant species to be propagated from seed and the prevalence of poor and infertile soils has made it necessary to explore other alternative means for rapid plant cultivation and growth. This study documents the effects of activated biochar (AB), and treated liquid and solid anaerobic digestate (TLD, TSD) derived from grass cuttings on stem propagation and growth performance of Mentha piperita after 60 days of treatment application. Analysis for nitrogen N, phosphorus P, potassium K and carbon C content of TLD, TSD and AB showed that AB was highest in nitrogen (10.91%), potassium (8.15%) and carbon (78%) content while TSD had the highest phosphorus content (2.1%). Results obtained for growth performance showed significant differences (P < 0.05) in all treatment groups. Plants treated with 250g TSD showed highest positive effects on all growth parameters after 30 days of treatment application while plants treated with 250g AB had the highest growth performance after 60 days when compared with other treatment groups. AB had slower but more lasting effects on plant growth due to the time needed for biochar to breakdown into useable forms.