Fred Clarke on Growing Australian Dendrobiums

Here are some culture tips shared by Fred Clarke when he spoke to us in November 2015 (thanks Fred! These tips apply to growing plants in Southern California, Encinitas is below San Diego):

Watering: Water and fertilize in Summer, grow plants dry in Winter through January.

Fertilizing: Pure water (not hard). Needs 15-5-15 Calcium-Magnesium formula at 100 ppm or half tsp per gallon (we do not need the high phosphate fertilizer to neutralize hard water), or 1.5 oz of fertilizer per gallon of water for a constant feed injector system (please disconnect in fall).

Light: Three thousand to 3500 footcandles, 55% shadecloth as a base, 35% shadecloth over that in Summer, or 65% shade year-round.

Media: Three parts Orchiata bark to one part perlite mix.

Dendrobium speciosum flowering habits: Flowers open during the day and close at night for five days before setting and staying open.

Repotting tips: Divide plants when new root tips begin to break (Spring).
Put on clean pair of disposable gloves before doing anything, put down several layers of clean newspaper. Flame pruning shears for ten seconds on each side (butane torch).
Divide plants into four bulb divisions. Date tag with time of division, so you know what time of year you will need to divide again.

~Paula Shiu

Published online on February 15, 2016