The aim of our study was to determine the dynamics of development of select groups of microorganisms and the activity of dehydrogenases in a substrate containing a microbiological inoculum (BAF₁) intended to improve scarlet sage growth and flowering. The material used in the investigations was peat substrate of 5.5-6.0 pH into which plants were planted and then inoculated with different doses of the BAF₁ biopreparation (1:10, 1:50, 1:100). Samples of the substrate were collected during the following three phases: seedling planting, vegetative growth, and flowering. The following parameters were determined: developmental dynamics of total bacteria number, actinomycetes, molds (Koch plate method), and dehydrogenases activity (spectrophotometric method). Moreover, plant morphological parameters such as plant height, shoot number and length, number of buds and inflorescences, as well as content of chlorophyll a+b, a, and b, and leaf greenness index (SPAD) were also measured. The application of the BAF₁ inoculant into the peat substrate contributed to increased number of heterotrophic bacteria, actinomycetes, molds, and dehydrogenases activity. The number of the studied microorganisms were stimulated most significantly by the applied foliar application of the biopreparation at 1:10 concentration, while their metabolic activity also was stimulated by the foliar application of the experimental inoculum applied at a concentration of 1:50.
The applied BAF inoculum failed to exert a significant effect on the number and greenness index of leaves or on leaf blade width and length. However, irrespective of the dose and method of application of the inoculum, it improved the degree of coloring of inflorescence buds and affected the length of inflorescences (in particular, the foliar and soil application of 1:50 concentration) and increased the chlorophyll content in plants (especially the soil application with the biopreparation at 1:50 concentration, as well as foliar application at 1:100 concentration).