A pot experiment was carried out during two successive
seasons,2005and 2006 in the greenhouse , at Ornamental Horticulture
Department, Faculty of Agriculture, Cairo University, to study the effect of
growing media on growth and chemical composition of croton plant.
Generally, growing the croton plant cv. "Gold Star" in a mixture of
sand+ peatmoss + clay, sand + peatmoss+ vermiculite or sand+ peatmoss +
perlite resulted in the tallest plants with the greatest number of leaves and the
largest leaf area. The mixture of sand + peatmoss +clay as well as sand+
peatmoss +perlite significantly increased stem diameter. Most of growing
mixtures had a favorable effect on increasing the number of branches of the
croton as compared with the mixtures of sand+ peatmoss+ sawdust and sand
+ peatmoss + dried leaves. The fresh and dry weights of leaves and stems
were heavier in the mixtures of sand + peatmoss +clay and sand +peatmoss+
vermiculite. The mixtures of sand +peatmoss +sawdust and peatmoss
+perlite, sand +peatmoss +clay increased the root length and fresh and dry
weights of roots of the croton plants.
The mixtures of sand + peatmoss + perlite, sand + peatmoss + clay
and sand + peatmoss + vermiculite were the most effective media in
increasing the contents of both chlorophyll–a and chlorophyll–b. The highest
value of the carbohydrates content in the leaves of croton plants was recorded
with the mixture of sand + peatmoss + vermiculite, The stem content of
carbohydrates reached the highest value in sand + peatmoss + clay mixture.
Using sand + peatmoss + perlite increased the accumulation of nitrogen in the
leaves, stems and roots. Adding vermiculite, clay or perlite to sand + peatmoss
mixtures had favorable effect on increasing the K content in the leaves of the
croton plant, whereas the mixture of sand + peatmoss + perlite increased K
content in the stems and roots.