Cotton gin trash compost and rice hulls as growing medium components for ornamentals

Rooted cuttings of Dendranthema grandiflora Tzvelev., Nerium oleander L. an d Lantana camara L., as well as seedlings of Pelargonium zonale L. were gro wn in media containing cotton gin trash compost, rice hulls, peat and perli te in various ratios, and their vegetative growth and flowering was determi ned and compared with a control medium of 1peat:1perlite (by volume). When up to 60% of peat in the control medium was replaced by cotton gin trash co mpost plant height was slightly reduced, except in P. zonale, the number of flowers was increased, except in pot D. grandiflora, and flowering was acc elerated in all species except N. oleander. When half or all the perlite of the control was replaced by rice hulls, plant height and flower number was similar to that of the control plants, except in pot D. grandiflora where the number of flowers was reduced and in cut D. grandiflora where both stem length and flower number were reduced; also, in L. camara total replacemen t of perlite by rice hulls gave shorter plants. In media that contained cot ton gin trash compost, peat and rice hulls, plant height of all species exc ept P. zonale was reduced. Partitioning of cotton gin trash compost or rice hulls in the media decreased their total porosity and their easily availab le water, while cotton gin trash compost increased bulk density. When rice hulls totally replaced the perlite, bulk density was decreased. The media w ith peat, cotton gin trash compost and rice hulls and the one with peat and rice hulls had the lowest easily available water and total porosity of all the media tested. Media with cotton gin trash compost had a high electrica l conductance at the beginning of the culture period, but it fell to the le vel of the control by the end.