Growing Guide for Orchids

Dear Garden Doctor, I have recently been given some orchids that have outgrown their old terracotta pots. What is the best way to care for them and best way to re-pot them, and which type of soil to use? What is best way to care for them and then get them to flower?

Thanks for advice in advance. Marcos, Bali.

One of the most common houseplants grown, yet so often misunderstood! There are over 25,000 documented species of orchid, the flower when in bloom has a bi-symmetry just like the human face, and did you know that the vanilla bean comes from a species of orchid?

It is some-what of a myth that orchids are difficult to grow – for most types it’s as easy as any other houseplant, provided the right growing conditions. While there are fussy orchids, on average there are many more types that adapt well to the temperatures and light conditions found inside the average home and garden. When starting out it is helpful to know that in a natural habitat, orchids, generally grow on rocks and trees beneath the forest canopy, obtaining nutrients from leaves, bark, bird-poo or anything else that falls from the sky.

At home, just as in the forest orchids will prefer bright, filtered light and a humid environment, and they can be grown both indoors and out. Too much light may result in leaves that are pale green to yellow, whereas insufficient light is often indicated by deeper green foliage. On positioning, they like a permanent home, resist moving them often.

Ideally, they should be planted in bark or rocky material, and never soil or potting mix which could cause root rot or at best a generally unhealthy plant. In a natural setting, orchids grow on rocks (lithophytes) and trees (epiphytes). By clinging to tree bark or rock-faces, the plants absorb water and nutrients from the air, rainwater and whatever else trickles down. They are adapted to surviving when rain is scarce, storing water in their thick leaves, stems and roots. Orchids can be mounted to, and grown on various surfaces including, tree fern bark, hardwood, driftwood, terracotta, rocks, logs, bark, branches, large shells, bamboo off-cuts or even trees out in the garden.

Potting an orchid in soil would be one of the best or worst ways to kill it – or at least make it very sick. The roots will most likely rot. Fibrous peat, rocks woodchips, charcoal, mosses, perlite, coir and bark are best to mix in combination, or used on their own as a potting medium for most orchids.

You can usually find specialised potting mix for orchids at the nursery or you can make your own – which is always fun and rewarding. Make sure that there is good drainage throughout the chosen potting medium as orchids like to have airy roots.

When you re-pot, make sure the top of the root growth is just below the rim of the pot. Orchid roots often creep over the edge of the pot before the body of the plant makes it to the edge of the pot. If you see that the body of the plant has grown over the edge or that the potting media has itself broken-down then you know that your orchid needs to be re-potted. After re-potting, most orchids will experience a period of slower growth for a while. This is normal and nothing to worry about.

Orchids like most flowering plants have a growing period and a blooming cycle. During the growth period new leaves sprout which store up energy for flowering. Eventually it will send up one or more spikes from which flowers will sprout usually lasting anywhere from a few days up to eight weeks depending on the variety. Displaying flowering orchids in cooler indoor temperatures will help prolong the bloom.

Of the more commonly available orchids, phalaenopsis (the moth orchid) will often re-bloom from an old flower spike. The spike should be cut between the scar left by the first flower and the last node (swollen, jointed area on the stem). One of the lower nodes may then initiate a new spike that can produce flowers within 8 to 12 weeks. Younger or weaker plants may not always re-flower though. For beginners obtaining the patience to wait for the next blooming cycle is one of the hardest things to attain!

Most orchids can handle less rather than more water, and flowering is much less likely if over watering occurs. If you’re trying to kill an orchid just put it in soil and give it loads of water. Never let the roots or the growing medium become saturated in water, this will cause root rot. How often you water will depend on how bright the growing conditions, how humid, and how warm it is, all factors that impact how fast the potting mix will dry. It is important to allow orchids to completely dry out between watering.

Too much fertiliser will kill an orchid whereas I have never seen an orchid die as a result of a lack thereof. Orchids do not require abundant doses of fertilizer. Seaweed fertilizer and fish emulsion are best for your orchids as they contain a mild balance of nutrients and trace elements that help it to thrive and flower. Another good idea is to supplement with the rice water from when you wash your rice.

Orchids need moisture, but never allow them to become waterlogged. When watering, allow water to run freely through the pot, otherwise mist regularly. If fertilising orchids, less is better than more, and remember that exposed roots are okay, but re-pot if the bark has totally decomposed.

In general, the Phalaenopsis, Paphiopedilum, and Dendrobium orchids are easiest to care for, so long as you can produce the correct environment for them. Taking care of orchids should be an enjoyable experience. By selecting the right environment, pot and fertilizer, you will be well on your way to enjoying a lifetime of beautiful blooming orchids!


Dr. Kris

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