Stockers' Nursery
Cultural Notes

Growing cool tropicals

The following notes are based on our experience growing these plants in open greenhouses on the Atherton Tablelands, north Queensland where cool to intermediate conditions prevail for most of the year. Our climate has many similarities with that of the Brisbane - Sydney region.

Tropical montane environments

The temperature fall on ascending mountains varies from place to place. For Papua New Guinea a rough guide is that up to about 500m the temperatures are much the same as they are at sea level (max 32 degC, min 19 degC). For every 500m above the 500m level, deduct 3.5 degC from the maximum and 3 degC from the minimum. However, remember that maximum and minimum temperatures in the micro environment in which plants grow may be differ from those published in official records.

A second aspect of temperature is the lack of seasonal variation at all elevations in the equatorial tropics. For instance in Papua New Guinea there may only be a difference of 1 degC among mean monthly maximums or minimums during the year.

The other important aspect of this environment is that plants, even twig epiphytes, very seldom dry out. Rain, fogs and mists are usually frequent. Low temperatures and high humidities contribute to low drying rates. Saturated conditions also ensure that plants are adapted to very low nutrient levels.

Suggested guidelines

a) Attempt to provide temperature conditions which are reasonable close to those of the natural habitat and in particular avoid extremes.

b) Use a potting medium which stays moist and is free draining.

c) Use fertilizer sparingly. Flush pots thoroughly between fertilizer applications. Some of these species appear to be very susceptible to over fertilization. Unfortunately few growers recognise the symptoms and over watering or root rot fungi often receive the blame for the death of the plant.

Good growing!