This is page 4 of the series that will help you choose different medium components for some of the more specialized houseplants you may have in your home. Some people feel that orchids are difficult but I feel that if you inform yourself with your orchids natural habitat you will know the medium, water and lighting requirements it needs. You will then be able to enjoy your plants and impress your friends.
by Mary Sue
Here’s the Dirt…page 4
Time to get sophisticated and get your hands dirty
When you know the needs of your plant you can combine any number of ingredients to create a perfect habitat or there are many commercial potting mediums based on the following components. The ingredients you supply to your plant will dictate your plants growth. Garden soil alone is unsuitable for containers because it may contain weed seeds, pests and diseases. The drainage often becomes poor quickly without the activity of worms and other animals once you put it into a pot and place it indoors. Finding materials to mix together to create the best environment for your houseplants has never been easier. We will begin by exploring the many ingredients you can use in many combinations to create many different habitats.
Know your orchids requirements. Their requirements vary quite a bit and if you are using a pot it is best to use one specially made for orchids. These pots have many and large drainage holes both in the bottom and along the sides. There are commercial orchid mixes available but here is a list of some components to get you thinking about mixing your own. Most of these are in the basic ingredients list with a few more added options that, of course, can be added to any medium mixture.
An orchid planted in moss prefers to be re-potted every 6 months to 1 year. Some, like Vanda, never like being disturbed but still need extremely careful re-potting perhaps every 2 years. Others, like Paphiopedilum, prefer to be re-potted perhaps every two years if the medium has not broken down earlier. After taking the old medium from the roots, again know your orchids requirements as some will not like the disturbance of removing the old stuff, and carefully inspect and trim any that are dead. The thick, fleshy roots may be stiff and break during re-potting but a good soaking before can help you gently bend things around and into the new medium.
Terrestrial orchids (i.e. Cymbidiums) plants that grow in the rich, loose, top litter of the forest floor. They will not tolerate water hanging around their roots.
Epiphytic orchids (i.e. phalaeonopsis) plants that grow on other plants without endangering them in any way. They often receive rain but dry out quickly in sun and wind. The larger the root, the larger the pieces of medium, and the larger the pot is a beginning guide.
– from the Douglas fir, uses nitrogen as it breaks down so orchids need fertilizer with nitrogen. Small ⅛”-¼” used for seedlings, medium ¼”-½” used for pots up to 3½”, larger for mature plants.
– use pine, fir, cedar, or hemlock bark all under the size of a dime. Used to aerate the medium and supply nutrients and minerals.
COCONUT HUSK CHIPS
– cut to uniform size, washed and pressed several times to leach out the salts. It is best to thoroughly rinse, squeeze dry, and rinse again before using. They hold water like a sponge, actually to the point of when squeezing a hydrated piece you can watch the water run out, and provide excellent aeration. When using be careful not to over-water which will encourage fungus gnats.
TREE FERN FIBER
– looks like sticks, breaks down extremely slowly and provides some nutrient value. Can be used alone in a pot or you will see it in shops formed into a pole that you can attach an orchid to.
SPHAGNUM PEAT MOSS
– is still breaking down. Sphagnum peat is humus but so very broken down that very few nutrients remain and is beneficial in providing a constant acidity that will hold water like a sponge. It is a good substitute for leaf mold if not available but will be without the nutrient and bacterial value of the leaf mold. Used to provide aeration, water retention and anchorage. It is harvested mainly in Canada and Europe and does involve destruction of the natural habitat of many plants and animals.
– an expanded clay that provides support and aeration, holds moisture, with ph 7.0
‘GROWSTONES’ HYDROPONIC GROWTH MEDIUM
– made from recycled glass and provides support and aeration.
– from the Osmunda (or cinnamon) tree fern. If dry, soak to re-hydrate a bit, and rinse off any dust. This will make it more pliable than other fern roots and you will be able to gently arrange it around your orchid’s roots without damaging them and give your plant the support it needs to stay in the pot. It can be difficult to work with.
CHIPPED REDWOOD BARK
– keep pieces small – ⅛”- ¼” if adding to other components and larger if using alone – this does decompose rapidly and will need replacing as it settles with decomposition.
MONTEREY PINE BARK
– used in large and small chips, holds moisture and nutrients well, and lasts 5-7 years before breaking down. Comes from New Zealand, often used for Epiphytic orchids and is sold under the name Orchiata.
– organic matter that is still breaking down, supplying nutrients, aeration and will hold moisture. Any of the 3 ingredients listed in the basics list can be added to a nice sterilized loam to provide the necessary food and aeration for most houseplants. It would be an excellent top dressing to freshen medium when not re-potting. (see basic ingredients list for more detail)
Whether you put your orchid into it’s special orchid pot or attach it to a tree fern pole be sure to water the plant first to make the roots as supple as possible and always moisten the medium so it will not wick away moisture from the roots when watered. Media recipes