Slipper orchids in a hot climate

Coastal North Queensland

Townsville/Thuringowa, Queensland, Australia is noted for its hot tropical sunny days, with high heat and humidity during the annual Wet season.

Many slipper orchids will grow quite happily in our climate when some basic requirements are met.

Culture notes

A good shady position is essential, especially during the hotter months when the plants are heat stressed.
Extra shade during the summer months will protect plants from the heat.
Pot size is important; the slippers should always be potted into a pot just big enough to accomodate the root system.
When repotting, remove old dead roots, place the root system in the pot and fill with the growing media.
A porous media is best, so that the roots are not sopping wet all the time.

Recommended media

A local grower who does very well with these plants uses the following mixture. ( A modest man, I wont mention names!)

Ray's mix;

6 to 8 parts dend size bark (half inch)
6 to 8 parts fine bark seedling grade
1 part of each of the following; shellgrit, perlite, vermiculite, isolite, and milled spaghnam.

All mixed together well. When potting, a small amount of nitrophoska fertiliser is sprinkled on top of the media to replace nitrogen uptake by the bark. After 12 months, Ray sprinkles about a teaspoon of dolomite on each pot to adjust excess acidity due to the bark mulching.

Benching and light

The plants like high humidity, and can be grown on a sand bench or close to the ground, but NOT under benches or other plants. They do need light, not a dark dingy corner. Excess wet weather rain can also be a problem, and some shelter is recommended. The best results seem to be had with seedlings raised from seed in the district.

Paphiopedilum rothschildianum, glaucophyllum, spicerianum, concolor, purpuratum, leimiana, chamberlainianum, lowii, primulinum, philipinense, wardii, roebelinii, laevigatum, niveum, godfroyeae and a few others have been successfully grown, indicating that local production from seed produces a better acclimatised plant for our hot tropical climate.

Paphiopedilum primulinum Hybrids of Paphiopedilum, with good hybrid vigour, are also grown well locally by several growers, and often figure prominently in Shows.

Recommended procedure; get a few seedlings and have a go.

Text by Ian Walters.
May be reproduced provided source acknowledged.