Growing Phalaenopsis
An agriculturalist's entry into growing Phalaenopsis
Ongoing medical issues over several years precipitated leaving behind a career lecturing in horticulture. Commercial honey production, pollination of tree crops, marketing of honey, and dabbling in cattle breeding became our focus for a time until these activities were curtailed on health grounds.
An initial gift of a Phalaenopsis amabilis was housed along with several other orchid genera in a standard domestic weld mesh shade house covered with medium density shade cloth. The Phalaenopsis collection has since grown to fifty as a consequence of rescuing a few ‘near dead’ from a Bunnings markdown trolley along with purchases from Robertson Orchids Woombye and Orchids Mackay at Mackay.
It wasn’t long before the growing environment in the original shade house was found to be less thansuitable to grow Phalaenopsis. After researching Australian and International orchid society technical notes and publications, consulting local orchid growers for their experiences, a 6 m x 1.5 m weld mesh shade house was purchased.
The roof is permanently covered with solar weave and overlaid with medium density black shade clothwhich also covers all four sides of the structure. The structure was positioned on the only available environmentally friendly site giving some protection from the hot westerly sun and east/south easterly winds. The shade house sits on a brick base with the internal pathway covered in 100 mm of wood chip. A single line of overhead misters is positioned internally under the roof.
Battery-operated mister
Overhead misters or a battery-operated mister drawing water from a bucket are used to drop ambient temperatures from the high 30’s to below 30 deg C. Troughs filled with water sit on the floor underneath the orchids to increase humidity.
Anthuriums grown under the benches assist with maintaining a humid environ- ment, along with misting and watering down the wood chip on the floor. All Phalaenopsis are hung from under the bench during the months of Nov- March providing a better temperature/humidity environment.
Light levels are measured and adjusted by adding extra shade cloth or removing same to achieve the recommended light levels 10,000- 15,000 lux. This has been a very hit and miss affair but to date all Phalaenopsis have managed to grow and flower reasonably well. There is always the concern that the environment is too dark.
Our experience has shown the growth parameters of temperature, light and humidity are extremely difficult to keep within acceptable ranges for growth and flowering in this type of structure and climate.
Potting mixes have varied (by deliberate experimentation) from single charcoal or scoria to combinations of kiwi orchid bark, pine bark, perlite, charcoal, coco chip and coco blend. Hard experience quickly concluded that large pots can hold too much water particularly when coco pith dominates the mix. Phalaenopsis although preferring roots to be kept damp do not like mixes which remain wet and soggy. We have found by allowing the mix to become almost dry hasn’t unduly affected growth to date. Our watering practices regularly need to be adjusted according to the openness or fineness of the media and the prevailing temperatures and humidity.
The Phalaenopsis have grown well in single charcoal or scoria but on occasions some orchids struggling in fine mixtures holding excess moisture have had to be repotted into a more open media mix. Phalaenopsis nutritional needs are provided using foliar applications of a biological fertilizer marketed by Neutrog rotated with Horticultural Solutions HSO 12 or 22. The timing of these applications is governed by the stage of growth, prevailing temperatures, visual identification of growth and general plant vigour.
Foliar applications of a liquid microbial inoculant sold by Growth products as ‘Companion’ andcontaining Bacillus subtilis is being tried. This product is marketed as a broad-spectrum biological fungicide for the prevention, control and suppression of soil borne and foliar diseases. Our limited usage suggests there may be some response by our orchids, anthuriums and bromeliads in growth and vigour.
Sticky insect traps
Yellow Sticky Insect traps are routinely used as monitoring devices for the presence of mites, aphids etc. Mealy bugs have been the most common pest in the Phalaenopsis shed. This insect pest was sprayed with Yates Confidor (now no longer sold) to kill the organism hiding deep in the axils of the leaves and in inaccessible parts of the plant. Scale insects have not been a problem. Spot applications of Eco Oil has been used to manage mites.
Eco oil spot application
Plants are hung above the bench in the cooler months and well-spaced to keep airflow to a maximum assisting with disease management. Wetted wood chip floorsand potted Anthuriums assist in increasing humidity In any agricultural enterprise plant growth, vigour and crop yields can vary from season to season as environmental conditions and cultural practices vary. We’ve found a variation exists within the Phalaenopsis genera in insect and disease resistance, tolerance to light, moisture and temperature regimes.
The framework for our Phalaenopsis growing system was developed using the advice of published experienced industry specialists and personal communication with Australian orchid growers. These sources of advice coupled with my background in agricultural crop and pasture production has helped to make sure no orchid has died but least grown and flowered if not anywhere near their full growth potential.
Author: Steve S