Have you checked your fleecy-lined slippers and your supplies of medicinal spirits? What about your orchids? Most epiphytic orchids like cold, wet conditions even less than we do. There are various steps you should undertake now to avoid being reported to the Royal Society for Prevention of Cruelty to Orchids!
Few epiphytic orchid species live further from the equator than we do here in Melbourne. It follows that during the winter they experience much shorter daylight hours in Melbourne, and that therefore we should do our best to give them as much light as possible. Conversely, they experience longer daylight hours here in summer, so living in Melbourne is not all bad!
Most of our cymbidium hybrids have been bred from Asian species that grow relatively close to the equator (there are three Australian species but they do not feature strongly in the breeding lines of most hybrids). Fortunately for us, most of the tropical cymbidium species used in hybridising come from mountainous habitats, rather than coastal ones, and they are therefore able to withstand relatively low temperatures at night. But winters in the tropics are relatively dry, in contrast to their hot, wet summers. We should try to duplicate these conditions when growing our cymbidiums – plenty of water in hot weather but much less in winter, especially during cold spells.
So, how do we increase the amount of light that our cymbidiums receive in winter, and protect them from cold, wet weather? For those who grow their plants out of doors under shade trees, the simplest solution is to move them under the eaves on the north side of your house. The proviso here is that the area is not excessively shaded by trees or by your neighbour’s house. A slightly less satisfactory alternative is under the eaves on the east wall but facing south or west is definitely out, because your plants will be exposed to our coldest, windiest weather there. Don’t forget that under the eaves, they will need watering regularly.
Serious cymbidium growers keep their orchids in a shade house fitted with a clear, corrugated fibreglass or polycarbonate roof. Shade cloth is best mounted about 300 mm above the roof to provide maximum cooling in summer. Preferably you should be able to remove the shading in winter. The solid roof provides two advantages – it avoids your plants remaining wet during prolonged cold, wet weather, and it prevents water damage to the flowers in winter and spring. On the downside, you have to water all year round but at least you’ll be able to provide water to your plants only when they need it. If you already have a solid roof, autumn is the best time to clean it. You’ll be surprised how much more light it will transmit after you’ve washed it down while scrubbing with a household broom.
If you already have a shade house and its design doesn’t allow for a fibreglass or polycarbonate roof, then consider covering it with temporary clear plastic sheeting during winter. Solar-Weave® is a reinforced durable material (1.8 m wide), sold by major nurseries, that serves well for about ten years before it needs replacing. I fit eyelets at 300 mm intervals around the edges and then tie it down over the shade cloth with fine wire. You will need a belt punch, eyelets and eyelet pliers (used for making ladies’ dress belts – try Spotlight or maybe Bunnings). I sandwich two extra layers of Solar-Weave under the eyelets to reinforce them. It’s important to support the centre of the plastic cover in some way so that in the event of rain, the water drains away. If not, you will create a monster birdbath, which will give you an unexpected shower if it gives way under the weight of water!