The Different Kinds of Potting Material for Orchids (An Introduction to Orchid Keeping, Part 2)

Guarianthe aurantiaca 'Anette' Photo courtesy of JM
Find the right amount of shade, water, sunlight, and potting media for your orchid to keep it healthy.

By Yvette Tan

Read Part 1.

You’ve picked the kind of orchid you want to grow. But keeping an orchid isn’t as easy as sticking it by the window and hoping for the best. These plants need a certain amount of water, shade, and sunlight, depending on what type they are. They’ll also need proper potting media, which will keep the plant anchored. Figuring out what you need can be simple.

Dendrobium anosmum var. coerulescens ‘Blue Moon’
Photo courtesy of JM

Here are some guides to go by:

Need for Shade… or Not

“The physical structure, or the location. You can either have a net house (thicker layers of net would give you shade) or put it in the open air, such as in the garden as part of the landscape or just beside your house under the eaves,” JM says. “What you’re trying to do is to control the sunlight.”

The rule of thumb is that the broader an orchid’s leaves are, the more shade it needs. “For example, the leaves of the phalaenopsis, or the moth or mariposa orchid, tend to be large compared to other orchids. Meaning bigger surface area, thicker and more fleshy. Since they are thicker, fleshier, and have a bigger surface area, they would require a great deal more shade than other orchids, so around three layers of net or plastic would be necessary for phalaenopsis.”

Vandaceous orchids love the sun, but how much sunlight you need to give them will depend on their leaf type. Terete leaf plants (thick, cylindrical leaves often described as “pencil-like”) don’t need shade, but strap-leaf (broad and flat leaves) orchids will need a “minimum of one layer of net.”

There’s a debate among orchid enthusiasts on which color net is best (you can choose from green, black, or white), but for JM (who prefers black netting), net color doesn’t matter as long as it shades the plants. “The purpose of the net, other than to give shade, is to contain moisture. Even if moisture is at gas level, it can still be contained by the net. This is important because you don’t want to water your orchids too often.”

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Hybrid Papilionanda Mevr. L. Velthius
Photo courtesy of JM

The basic rule is the younger they are, the more shade they require. “For example, a two to three-inch seedling would require around three to four layers of net so that they will not be scorched by too much light,” JM says. “As they grow, you peel off the extra layers of net.”

JM stresses that there’s no formula about the shade you need to give your orchids. “You just have to observe the orchid. If the orchid is robust, the leaves are shiny, the roots are active, then it is happy. But if the leaves are flaccid, lose their rigidity, and the roots are not active at the end, meaning growth has stopped, that means it is stressed. You have to give the right sunlight requirement and proper nutrition.”

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Cattleya (Old Whitey x loddigesii)
Photo courtesy of JM

Speaking of Watering…

It is easier to kill your orchids by overwatering than by underwatering. “Water is imbibed through the roots or through the stomata, underneath the leaves,” JM explains. “You have to determine if the roots are fleshy or wiry and fibrous.”

“Orchids that have fleshy leaves like Phalaenopsis and Cattleyas tend to rot if you overwater them. That’s why they have to be protected from excessive rainfall,” JM says. “Cattleyas and Vandas do well just underneath the eaves of the house, whereas Dendrobiums can thrive either in full sun or in partial shade, with a minimum of one layer of net. Pero pag full sun siya, may tendency na ma-scorch yung leaves kapag summertime.”

An orchid’s roots also gives you an idea on how to water them. “Monopodials (has a single root or rhizome) like Vandas and Trichoglottis tend to have fleshy roots. They can be watered once to twice a day, except during the rainy season, when they don’t need to be watered at all,” JM says. “Sympodials have a single rhizome or root with a series of bulbs growing up from it that hold water. That explains why they have small roots—because they already have structures to store water. Water these orchids—such as Dendrobiums, Cattleyas, Catasetums, and Cymbidiums—sparingly. Just once a day.”

The most important thing to remember, no matter what orchid you have, is that orchids should be watered in the morning. The plant should be dry after 5pm, particularly the tips of the leaves, which tend to store water. “Stored water can cause rotting,” JM explains.

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Guarianthe aurantiaca ‘Anette’
Photo courtesy of JM

Planting Material

Planting material is also important. These keep the orchid anchored and can add to the plant’s overall aesthetics. Since orchids are air plants, it derives little to no nutrition from its planting material. Choices include:

Charcoal: “You can recycle charcoal as often as you like for as long as they are intact,” JM says. “The production of charcoal might be contrary to the Clean Air Act, but they do make fantastic orchid media.”

Fern chips: “These are derived from trunk bases of giant tree ferns, and it takes decades, or even hundreds of years for one tree fern to have economic value,” JM says. “There is a debate on its sustainability and I think there is a law prohibiting fern extraction from the wild. But again, they make good media.”

Coconut husk: “This is a sustainable material for orchid medium,” JM says. To prepare, submerge chunks of mature brown coconut in water for three days, changing the water each day to remove its tannin and resin. It is important that you use mature coconuts, as their fibrous husks offer better drainage. JJM cautions against using young (green) husks, as they are tough and impermeable to water. They also offer a less stable base because they tend to shrink or expand depending on whether they are wet or dry. “Immature coconut chunks also attracts molds and algae, which can kill the roots of your orchids,” JM says.

Rocks: Rocks need to be of uniform size. JM says that whether to use rough or smooth rocks is entirely up to you, though keep in mind that smooth rocks dry faster then rough ones. Also remember that rocks are heavy. However, since they don’t decompose, you can use them for as long as you want. “I use is pumice from lahar cut into manageable sizes,” JM says.

Wood: If using wood chips, make sure they are the same size as charcoal. You can also use tree bark, though it tends to disintegrate fast. “You can also use moss. Green moss is fine, but since they are alive, they tend to have lots of seeds in them and they will disintegrate within three months,” JM says. “A better moss would be white moss either from Chile, China,or Taiwan because they are of good quality and they will last longer.”

Driftwood: These are pieces of wood with a concrete or metal base to keep it upright. This setup basically mimics how orchids thrive in the forests.

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Row of Waling-waling (Vanda sanderiana) seedlings mounted to wood
Photo courtesy of JM

Styrofoam: Styrofoam has no nutritional value for the orchids. However, they make good extenders, nicely tucking your orchid in place. They also make excellent drainage. “For example, if you have a closed pot (a pot with a hole at the bottom), you can put the styropor at the base before you put the charcoal, fern chips, or coconut on top so there will be no contact between your organic potting material and the base of the pot,” JM says. “Because where they have contact, water will tend to react with the organic matter, causing acid. Your orchids will not be happy with acid bases.”

Almost anything, really: “Here in a tropical country, we have a lot of options. Basically anything, even PVC pipes can be used as clinging materials for vandas. Even net,” JM says. “For PVC pipes, we wrap it in patapon na black net, simulating tree bark, and that’s where we mount the orchid. Again, there are no nutritional values but it will not deteriorate. Dadalasan mo lang ang watering kasi wala siya masyadong water-retentive properties unless i-wrap mo siya ng paulit-ulit.”

Remember to keep your orchids’ planting media fresh. “If you use coconut, you can change it every two years, but if you fertilize often, mas mabilis ang deterioration, so you have to change it once a year,” JM says. “But if you use charcoal, you can change it once every 2-3 years. For pebbles, you don’t need to replace it at all kasi di naman siya nabubulok.”

Read Part 3, where we discuss fertilizers and insecticides, and how to best apply them.

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Yvette Tan
Yvette Tan is Agriculture magazine's managing editor Agriculture.com.ph’s web editor. She is an award-winning writer who likes to eat, travel, and listen to stories about the strange and supernatural. She is dedicated to encouraging people to push for sustainable food sources and is an advocate of food security, food sovereignty, and the preservation of community foodways.

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