2019 ASHS Annual Conference

Vermicast and rock powder are common natural growing medium amendments that promote plant growth, but their specific effect on root cuttings is understudied. This experiment was performed to investigate the effects of vermicast and rock powder pretreatment on the rate of rooting in different plant species. The experimental treatments (1) 10 g of vermicast+15 g of rock powder; (2) 10 g of vermicast alone; (3) 15 g of rock powder alone; and (4) distilled water as a blank control were applied on three different plant species, namely; tiger nut (Cyperus rotundus), Jamaican thyme (Plectranthus amboinicus) and Malabar spinach (Basella alba). The different plant species responded differently to the vermicast versus rock powder and their combination. The rock powder had the highest effect on Malabar spinach root length of 46.7 cm at week 5 after planting followed by 39.6 cm for plants grown in the combination of vermicast and rock powder. The response of the Jamaican thyme roots to water treatment was 43% more compared to vermicast. Jamaican thyme plants grown in the combined treatment had the least response, which was about 59% less compared to the water treatment. The enhancement of root growth by rock powder and water was similar at 16 cm at the end of week 5 of the experiment. The combined vermicast and rock powder performed well on tiger nut up to week 3 when it remained relatively constant just like the vermicast treatment. However, the vermicast treatment had a consistently least effect of 4.4 cm tiger nut plant root length. In conclusion, rock powder can potentially be used as a root enhancer but further studies will be required prior to recommendation.

Key words: Vermicast, rock powder, Basella alba, Cyperus rotundus, Plectranthus amboinicus