The composts were obtained
from the municipal sewage treatment plant in
Stargard Szczeciński and their maturation period
was 14 months. Chemical analysis of the composts
was performed at an accredited laboratory of
the Chemical and Agricultural Station in Szczecin
and its results are showed in Table 1. The composts
were mixed with high peat in two proportions
1:3 (v/v) and 1:7 (v/v). Given the results of
the chemical analysis of the growth media carried
out at an accredited laboratory (Table 2), nitrogen
and potassium deficiency was supplemented
with ammonium nitrate (34% N) and potassium
sulphate (50% K2O) up to the level recommended
for pelargonium [Komosa 2003].