Part I. Introduction of the Orchids substrate
There are two types of substrates be used in the
growing of Phalaenopsis, bark and Sphagnum moss. In
Europe, the fir bark mixed with others
substrate was selected. The sphagnum moss is very popular in Asia,
especially in Taiwan, China and Japan. Which substrate is better for the
growing of Phalaenopsis?
The functions of the substrate for the orchids
Provide the water and nutrient
Maintain the aeration of roots
Served as the anchorage for the fix of roots.
Different substrates have different characteristics.
Coarse particles such as bark and coconut fibers could provide more
space for the air. However, the water holding capacity is poor. Fine
substrates, such as sphagnum moss and fiber peat had the good water
holding ability. The disadvantage for these materials is the poor
aeration function. The adequate substrate need to maintain the
sufficient oxygen for roots respiration, provide the space for roots
development and provide the water and nutrient continually. In other
words, a good substrate could keep the balance between the water and
air. Coarse particles are good at the air aeration and increase the size
of cavities. Fine particles maintain more water and nutrient.
The characteristics of the Phalaenopsis roots
are exist of the chloroplasts as the organs have the photosynthesis
function. The national habitat of this orchids is the epiphytic plants.
As the roots are exposed to the air, they could absorb the moisture from
the air vapour, or the water.
Beside of the characteristics of aeration, water and
nutrient holding ability, the others requirements of substrates for
growing of Phalaenopsis include:
It should be long-term stability, not rot or decompose within a
few of month.
It should not contain any toxic materials.
It should have the enough space for root development.
It should be able to fix the orchids.
It should absorb water quickly and release it with vapour slowly.
It could absorb nutrient and release it slowly.
It should be supplied the mineral addition of Calcium and
By the above requirement no substrate could meet all
required conditions. Sphagnum moss is so popular in Asia region. The
substrate is very useful for the deflasked plantlets. As the plantlets
were taken out from the flask, they are very easy to be dehydrated.
Sphagnum moss has the excellent water holding ability and could be the
adequate substrate for these younger plants. However, the sphagnum moss
made the transplanting work very difficulty. It is not easy to pull out
the moss form the roots. The root was easy to damage in this moss pull
operation. The other method is to surround the old moss with the fresh
moss. However, the old substrates could be de composed and increase the
pH value of the substrate.
The bark was not utilized directly in the
Netherlands. The mixing of the substrates are the basic technique for
different crops. For example, some mixture substrate was composed of 90％
of the coarse parts and 10％
of the finer parts. The mixing of two kinds of substrates must be
uniform in the pot. Some nutrients were added into the mixture.
According the content of the Cultivation Guide
Phalaenopsis – Knowledge for professionals (Anthura B. V. and Bureau
IMAC Bleiswijk B. V.), there are two mixtures recommended by Anthura B.
10 kg Agrofoam 10mm, 25％
Peat dust fraction 1, 45％
200 liter perlite, 3 kg/m3 Dolokal ( for pH level adjustment)
and 35 g/m3 microelements.
PE flakes, 2.5 kg/m3 sphagnum, 55％
fine bark, 15％
medium bark, 2 kg/m3 Dolokal, 500 g/m3 PG mix (basic nutrients).
The substrates introduced by above Culture Guide
Polyurethane or polyether clumps (PE flakes)
Sphagnum: especially used at the start stage to help the good
moisture distribution in the pot.