Orchid Growing Substrates

watering/fertilizer solution, applied only to damp, but never water the mix. It was an art, but working
well.
- The hidden peat. Many companies blending mixes of various ingredients, for commercial purposes,
with lime and slow release fertilizer (usually PG Mix) use a very low amount of peat to dilute the initial
ingredients, and help for their dispersion during the blending process. It is usually very fine graded
peat of not really good quality, and it can pose problems, when the roots of the plants encounter it, if
they are sensitive to low pH it can stop them. For a Phalaenopsis or a kitchen table dendrobium, it can
be fine, and the root will die, that’s it. For some sensitive Paphiopedilum, that make only few roots
per year, losing a root tip this way, and the usual root rot that follows can be a disaster. In the
Netherlands one grower lost benches and benches of Paphiopedilum just because of the low quantity
of peat added, that settled at the bottom of the pot, in a really minute amount, but was at a pH of 3.7.
- Peat can be really acidic, and values down to 3.1 are not unheard of. It is usually blended with
dolomitic limestone by some sellers, though some people sell it straight, and it is up to the grower to
correct the pH. It is always best, if someone wants to buy straight peat, to buy some of the famous
brand ‘buffered’ peats, even with the micronutrients and fertilizer blends included, though we no
longer can recommend the use of peat like it would have been possible over two decades ago.
Nevertheless, it has never been a long term potting mix or even potting ingredient.
Coconut and coco products.
- Xavier has been one of the first users of shredded coconut in Europe for Orchids and especially
Paphiopedilum in 1992. At that time, it was usually limited to some Asian and African countries, which
had ready access to coconut. In those days, the results were absolutely amazing, blended with bark.
However, the product of that time, that helped to establish the fame of the coconut products for
orchids, and many other crops, will never be available again. Here is the story.
- The Sri Lanka Orchid Society published a pamphlet in 1952 regarding the use of coconut for planting
orchids. It is the earliest mention in a ‘westerner‘publication of the use of coconut for planting
orchids, though it was done in those days already by some growers in Asia. It is funny to note too that
Sri Lanka would become, nearly half a century later, the ‘base’ for coconut products production
around the world.
- In the 80’s, some people oversaw huge stockpiles of rotting and rotted coconut shells, sometimes
decades old stocks. They had the idea to process it to make potting mix. The fines went to make a
kind of peat, and the intact parts were crushed, to make a kind of thing that was akin to the long fiber
peat moss, brownish black, fluffy, retaining a lot of water, like a sponge. It would look like torn apart,
pieces of a brand new brown coconut shell, but of a black color, and completely water absorbent. The
coconut had been weathered for ages, and it had no longer any salts, except the powder, that was
harvested at the bottom of the stockpile, and could contain both sea salt and sand as a bonus, not to
mention fusarium spores and a wide range of weird things along with insects. However, those
shredder pieces of black weathered coconut, mixed with big size European bark, that was still of
Xavier Garreau de Loubresse
18