Culture of Cool-Growing Australian
Native Dendrobium Orchids

(The Cedarvale Way)

These notes are intended to cover growing in shade-houses, etc,

as well as landscape plants.

POSITION – Semi-shade with good air movement but not strong winds, eg, westerly. If in a bush-house preferably 50% shade.

LIGHT – Bright light is required for flowering; will tolerate full morning sun but avoid direct western sun from 10.00am onwards especially in summer.

VENTILATION - I believe that ventilation is the most important aspect of good orchid culture in general. "Orchids love to be wet and love to be dry" and good ventilation will dry them rapidly, dramatically reducing fungal and bacterial rot occurrences, reducing the need for chemical sprays and thus saving you money.

WATERING - This really depends on your conditions for ventilation, humidity, light and shade, covering of shade cloth or fibre-glass, potting medium (eg, bark, sphagnum moss, peat/perlite, coconut fibre), plastic or clay pots. Our bush-houses are on the side of a hill in full sunlight without any surrounding trees, sheds, houses, fences, exposed to all the breezes and strong winds. Unless you have the same conditions your watering program will be different to us and other growers. In general we water every day or second day in summer (if not raining) and once per week in winter. The best method is to check the potting medium and if it is damp do not water. (More orchids are killed by overwatering than any other action).

RE-POTTING - We only repot when the orchid reaches the sides of the pot. However our potting mix will only last two years and the orchid should then be repotted with fresh medium. We mainly use 70% bark and either 30% jumbo perlite, 15mm Maidenwell Diatomite or 25mm Maindenwell Diatomite (depending on pot size) as a potting medium, 10mm grade up to 100mm pots, 15mm for all else up to 200mm with 20mm or 25mm for larger pots and Den speciosum from 150mm upwards. 

FERTILISER - We use 2 liquid fertilisers, one with a higher nitrogen value, NPK 14:5:22, from September to February and another with higher phosphorous and potassium values, NPK 7:11:27 from March to August. We use both of these at 1 gram/litre and (attempt to) apply weekly - weakly and weekly (how many times have you heard that?). We supplement with magnesium sulphate and calcium nitrate not available as trace elements in these fertilizers.

MISTING - In an attempt to simulate the conditions at 600 metres and above from March onward we lightly mist the plants at dusk to drop the temperature a few extra degrees to promote good uniform flowering in Spring. This continues until early May when we get consistent overnight temperatures below 10ºC.
 

PH - We believe that correct PH is extremely important in good culture and we set about to establish the PH of the bark at 6.5 to 7.0 at the initial use and we use calcium carbonate (lime) to spray the nursery twice a year (Autumn and Spring) to endeavour to maintain this PH level.