When growing orchids, it is crucial to use the right potting mix. Each variety of Orchid has slightly different requirements so it is important to find a mix that is appropriate. These can usually be found at your local garden centre or online, but you can also add to it yourself, changing combinations until you find a medium that works for you and that will provide you with the correct levels of water retention and aeration.
As a rule, Phalaenopsis, Cattleya, Dendrobium and Vanda varieties should be potted in a medium-grade potting mix whereas Paphiopedilum, Miltonia, Odontoglossums and Oncidium varieties require a finer mix.
Choosing a Potting Mix
There are literally hundreds of different kinds of orchid mix on the market today, and it can be difficult to gauge which one is right for you.
For beginners, a fir bark mix is usually recommended due to its value for money, ease of availability and, most importantly, the results it produces.
However, you should be aware that it tends to break down a little quicker than other potting mixes and will result in you having to re-pot your Orchids a little more frequently; fine grade mix particularly, holds more water and will break down even quicker.
You could, alternatively use a red wood bark which holds water better and will decay more slowly.
Coconut husk is also highly recommended for growing your orchids, again, due to its being inexpensive and readily available. It holds water well and will produce good results, however, as with fir bark, it decays quickly and so your plants will require re-potting on a fairly regular basis.
An alternative would be to use coconut fibre, which is longer lasting but has a high salt content and must be thoroughly leached out before use.
Sphagnum Moss is considered an ideal growing medium for smaller seedlings and plants that are in ill-health.
It provides a good ratio of water retention and aeration, but should not be packed too tightly, however it is liable to rot fairly quickly, and if due care isn’t taken, can lead to rot in the plant itself.
You should ensure that, if using this particular type of medium, you use a high quality product and not be tempted into buying inferior products available on the market.
Providing you get the growing conditions right, a Peat-based mix can result in fast growth for your orchids, but, can also result in a very quick death should you get it wrong.
It is vital that, when using this kind of mix, you take extra care during cold, wet winters and will need to use fungicides regularly to prevent infection.
Inorganic Potting Media
There are also a number of inorganic products available on the market;
Charcoal for example, takes a long time to decay and is great for absorbing toxic substances;
Lava rock provides good drainage but can be heavy;
Pearlite is great for water retention and decays very slowly but is very light and if used alone will retain too much water and should be used with another product to ensure proper drainage.
You should always consider outside factors when growing your orchids. Light, heat and humidity all need to be taken into consideration and will ultimately effect the combination of products you eventually settle on.