Cymbidium Orchids need sunlight, water, fertilizer, fresh air and a well drained potting mix to give best results
Cymbidiums need plenty of sunlight or they will not flower. However in our Adelaide summer, they also need some shade during the middle of the day to prevent the leaves from burning. If grown in a shade-house a shade-cloth of between 50% and 60% is recommended. If grown in the open garden, stand your pots just off the ground in a position where they will receive full morning sun but shaded during the middle of the day, from say a deciduous tree with not too heavy a canopy. A good test of your light conditions is to observe the leaves if they are a dark green instead of a light green they are not receiving enough light.
Your Cymbidium plant should never be allowed to dry out. Once the top 4 to 5 cm of your potting mix feels dry the plant needs watering. Plants however must not be kept continually sodden. It is preferable to give the plant one heavy watering rather than several light ones. Humidity is also important & can be creating by spreading materials such as sawdust gravel scoria on the ground under the benches, which will retain moisture & release it during the heat of the day your benches containing the pots should also be as close to the ground as practical to make best use of this humidity.
A good balanced fertilizer is required during the growing season (June – December) and a high Potassium fertilizer or blossom booster during the flower initiation season (January – May). Fertilizers should be applied at . strength on a weekly or fortnightly basis all year round. A slow release fertilizer can be used in moderation. A teaspoon full around the top of a 6” pot is sufficient.
Cymbidiums require plenty of air movement to do well. Stands with wire mesh tops and good spacing between the pots will help achieve this. If possible space your plants so not to have the leaves touching each other, or with at least one to two pot widths between them. Good air movement will prevent insect & fungal problems and help the plant to flower.
There are many different composts in use. The main requirements being that the mix is open, will not break down too quickly, and will hold moisture without being saturated. Common ingredients used are pine bark, sand, rice husks, peat moss, foam granules and marble chips. There are several good ready made cymbidium orchid potting mixes on the market in Adelaide available from nurseries and garden shops.
Cymbidiums seem to require a drop in night temperature to about 15 degrees C to initiate flower buds during December to February even if only for a short period. This can be achieved by giving the plant a short overhead watering about sundown.