Sunday, March 05, 2006

Tree Fern as Potting Medium

Tree Fern as Potting Medium

Written by [Philippine Orchid Review] Vicente Chin
Monday, 01 April 1985
Tree fern is a tedious medium to use for potting orchids, but the results are very satisfying because it encourages abundant rooting and deteriorates quite slowly (2-3 years). Cattleya orchids especially favor this medium for potting.
Tree fern need to be chopped (1”), shredded, and washed thoroughly before it can be sued for potting orchids. For additional safety, it should be boiled or soaked in a 10% chlorox solution for pasteurization. Tree fern requires plenty of rinsing before the water becomes clear.
Ideally, the coarser fibers are used for bigger plants while the finer-textured fibers can be used in seedlings or semi-terrestrial orchids or other orchids that like more moisture.
To obtain excellent drainage and aeration, the pot should be filled from ¾ to ½ full of big size charcoal. Your local microclimate will determine how thick a topping of tree fern you should use. Dry and windy areas will use a thicker layer of tree fern, while shady and humid areas will require a thinner layer.
Fibers can be aligned either vertically or horizontally, depending on your local climate. Vertical arranged fibers will allow faster drainage.
It is important to pack the fibers very firmly for cattleyas and vandas, but it should not be so tight that you injure your hands or the rhizomes in packing the fivers. Make sure that you finish potting with the surface of the medium very level. Uneven surface will produce crooked rhizomes in cattleyas. Pull out and re-insert fivers that stick out from the surface.
Compare to all charcoal potting, the tree fern topping lessens the frequency of watering. Be careful not to over water. Fill the inside through the bottom hole for moisture or inspect the pseudo-bulbs for shrinkage before you water.
Regular feeding should allow until the plants established or when new roots are starting to come out. Feeding must be very light initially (1/4 strength) and later increased as more roots are developed.
For convenience, slow – released fertilizer granules ( Gaviota ) may be use once the plants are fully established. Use only 1/4 to ½ the rate recommended for terrestrial plants every three to four months.
Very young orchid are safe with foliar feeding because there are more susceptible to burning ( over fertilization ) by the use of slow release-fertilizrer.
Experience will guide you whether more or less fertilizer can be use by the plants. Exercise caution because orchids are easily killed by over use of fertilizer.
Take care not to expose this medium to constant moisture as algae will soon invade this medium. Adequate protection from continuous rains with plastic sheets framed over the branches will lessen the change of algae infestation.
Slight drying between watering as well as regular Physan spray specially during rainy season should help prevent algae.
It must be admitted that this medium is rather tedious, but it help me to consistently grow quality plants fit for exhibition/competition.


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