Orchid Articles: Growing Orchids 2
By: Colin Silver
Orchids belong to one of the largest families of flowering plants with over 25,000 recorded species. They grow on every continent of the world except Antartica. Orchids are quite unlike other plants in terms of their mode of growth, the formation of their flowers and production of seed. Perhaps this is part of their irresistible appeal and what drives us to want to own and grow them. Because of their diversity and geographical dispersal there will almost certainly be a genus or two that will grow well in your particular area, without having to make drastic and expensive 'climatic' condition changes. For the purpose of this series we will focus on genera which will do well, but not exclusively, in the area of subtropical coastal KwaZulu Natal.
CATTLEYAS - are epiphytic orchids and are probably the most flamboyant and easiest to grow. They are mostly sympodial in growth habit and form pseudobulbs that are in fact swollen stems. These provide the plant with water and nutrition during dry spells. Cattleyas may be grown in pots or tied to wooden rafts or even into trees, where they will quickly develop masses of new roots and attach themselves permanently. If grown in pots, it is very important to ensure quick efficient drainage by using an open mix, e.g. pine bark or polystyrene chunks, hard nut shells etc. It is also imperative to provide additional drainage holes in the bottom of the pots.
Plants will only require re-potting once they start growing over the rim of the pot. This can be done at any time throughout the year, but preferably in early spring, when new roots appear at the base of the leading pseudobulb. The new pot should allow room for two years growth. Potted Cattleyas should be watered no more than twice weekly during summer and substantially reduced during winter. More plants are lost to over watering than to any other cause.
It is preferable to water during the early morning to enable plants to dry before the night time drop in temperature.
The colour of the thick fleshy leaves is a good indication of light requirements. A light green colour indicates sufficient light while a dark green indicates that light should be increased. Normally plants will grow happily under 30% - 40% shade cloth.
Temperature requirements are easily met in our area, i.e.: a minimum of ± 10°C and a maximum of ±30°C. Short spells of temperatures outside of these limits will not have a drastically adverse effect on plants. Cattleyas thrive in the constantly high humidity during our summer months. Fertilize your Cattleyas with Seagro, diluted Guano or Multifeed P during the growing season, but when fertilising orchids remember "weakly weekly".
