Dendrobium
Dendrobium – Basics
Sunlight : 50 ~ 75% daily.
In orchid nurseries, nets are cast above the plants to create a semi-shaded environment (lath houses). This creates an environmental condition of 50 ~ 70% sunlight, which is conducive for growth and flowering and prevents leaves and flowers from sunburns. Unfortunately, such measures are not practical for most private collectors or home growers yet this does not mean that Dendrobiums can be deprived of sunlight. Sunlight is still the most important element, alongside water, to ensure a healthy plant and its flowering. For non-nursery environments, Dendrobiums should be exposed to at least 8 hours of sunlight a day. Look out for areas in your garden or home that are adequately exposed to the sun.
Water :
Watering is slightly trickier than sunlight, as it depends on environmental factors and pot medium. On a serious note, incorrect watering can induce plant death. Bear in mind that excessive watering induces root rot which promotes fungal growth, and other symptomatic issues (which is more detrimental than watering too little). That is why proper orchid pots are porous to allow excess water to sieve through. Moreover, Dendrobiums are typically grown in charcoal – just the right type of pot medium that does not retains excess water, and allows roots to “breathe”.
Optimally, Dendrobiums can be watered (mostly onto their roots) during times of the day when sunlight is mild (approx. 8 ~ 10 am ; 4 ~ 5 pm). These are times of the day whereby orchids can best absorb water for photosynthesizing (feeding); and there are several hours of daylight thereafter to help evaporate excess water. Watering during mid-day; or in the hot sun could “shock” the plants. Most of the principles behind orchid care lies in being gradual. Analogically speaking, it is very uncomfortable for the plants to be splashed with cool water when they are already heated up in the hot sun.
Dendrobium – Advanced
Growing upright
A simple technique is to tie the stems together – not too tightly, but just enough to keep them growing in a desired, compact manner. This is particularly effective when performed on younger Dendrobiums – as in building a good foundation.
Trimming & Pruning – Flowers
It has been said that cutting off Dendrobium flower stalks can spur production of more flowers. This is true with certain ambiguity in need of clarification. Technically, blossoming flowers are signs that conditions are right, and at the right conditions, the Dendrobium plant desires to propagate its genes – thus producing flower. In simple terms, cutting off the flower stalks will trigger Dendrobiums’ “survival instincts” – where its desire to flower is disrupted, thus encouraging it to produce even more flowers for compensation. However, the key is to cut the flower stalks before it fully blossoms. If one allows all flower buds to blossom and wither off, it is not going to make a big difference to cut it off or not. Harvesting the flowers prior to full bloom inclines flowering to a certain extent.
Re-potting
A common question posed is “why re-pot?”. Understandably, re-potting will subject the Dendrobium plant (in fact, all varieties of orchids) to certain degrees of stress. Moreover, root systems of Dendrobiums will take up to 3 ~ 5 months to re-established themselves in their new pots. And in unfortunate cases, re-potted Dendrobiums may stop thriving or end up dying. But this section hopes to alleviate some doubt, and also some fear with regards to altering the state of one’s plant rather drastically. To put things into perspective, the recovery time for re-potted Dendrobiums is relatively short, compared to other types of tropical orchids.
Re-potting is commonly done for 3 reasons:
1) Switching to a bigger-sized pots for more growing space
2) Propagating and growing of new pseudo-bulbs/keikis
3) The new pot is prettier
Larger pots provides adequate space for its roots and pseudo-bulbs to grow, which in turn, signals that the plant has adequate space to grow as a whole. In most orchid nurseries, pot sizes used for Dendrobiums are usually capped at around 25 ~ 30 centimeters (10 ~ 12 Inches) in diameter. Such sizes are trialed and tested for Dendrobiums to achieve their maximum height (varies between 1.3 ~ 2 meters amongst hybrids).
Care needs to be taken when one is cutting off unproductive old roots/stems, prior to re-potting – to avoid injuring the pseudo-bulbs. It is highly advisable to treat the plant/keikis with fungicide as cuts made are open wounds after all. Moreover, new charcoal can be used as they contain less pest/pathogens. Also, line the Dendrobium plant nearer the surface of the charcoal medium, rather than right at the bottom of the pot. This is because Dendrobium roots prefer to “breath”. Crucially, the re-potted Dendrobium should be secured in a stationary position for months to establish itself firmly.
In Toh Garden, Dendrobiums seedlings are grown in communal trays for several months, prior to growing in small pots. The small pots provides adequate space for a healthy root cluster to form; and limited peripheral space aids in upright growth of Dendrobium plantlets. Or rather, bigger pots have excessive peripheral space, allowing outward/side-way growth, instead of upright growth.
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Dear Silverelf,
My dendrobiums have been producing new flower stalks (one plant has as many as 5 new flower stalks emerging!) but sadly, the flower buds don’t seem to be developing to maturity and the buds dry up and fall off. What do you think the problem is? I’ve never had this problem before. I leave my dendrobiums on a bright patio with morning sun, and shelter from afternoon sun. I water them once a day in the morning, and give them orchid growth fertiliser which I bought from Toh Garden twice a week (or once if I’m feeling lazy). I’d really appreciate your views! Could I be over fertilizing them? Thanks! Niki
Dear Noraini Aziz,
There can be several possible cause for this to happen. Some common causes could be due to root rot, insufficient sunlight or even pest attacks. Its unlikely due to over fertilizing if you use 1tsp per litre of water and don’t fertilize more than twice a week. It will be good if you can email us a few photos of your orchid so that we can identify the issue for you.
Cheers
silverelf
Hi, I live in NZ and I am finding it hard to get accurate information regarding pruning my orchid.
Would you have a picture of how far down to trim the canes. I have about 6 canes with no leaves. Thanks.
Hi Anna,
Do not trim the canes, instead separate them from each other by pulling them apart or cut along the sides like how you separate the keikis from the mother plant. I suppose you are referring to Dendrobiums?
silverelf
Hi there,
I’m trying to grow my first orchid plant which is a dendrobium. I have some questions which I hope you can answer.
First, I read on other websites that the orchids require mounting. May I know what is a suitable mounting material for my dendrobium which also has a weak stem and can’t grow upright?
Second, I would like to know what kind of soil is suitable for orchids?
Thank you for answering my questions.
-Kate
Hi Kate,
I suppose that your Dendrobium is not potted yet that’s why you need to mount it. You can mount your Dendrobium on a piece of bark or drift wood using wires. Alternatively, you can also grow it in charcoal with a stake for support. If your Dendrobium is weak, try growing it in more shade before growing it in 50% shade. This will assist it in recovering faster.
This depends on what orchid you are growing. Soil is usually suitable for orchids like Arudina, Spathoglottis etc but you can’t use soil to grow Dendrobiums as it will cause root rot etc.
silverelf
Hi,
My hubby bought 2 miniature orchids that are planted on seashells, which I think they are smaller breed of Dendrobriums. We placed them in our laundry yard and within a week, the flowers dried up and dropped off despite we misted it very frequently. It’s only recently we shifted them to our living room near our full length window where we have pretty strong sunlight coming in between 3-4pm. I cut off the orchid spike and spray some flowering foliage spray to induce flowering. Leaves are pretty bright green for now.
I’d like to understand:
1)Are we subjecting them too much sunlight?
2)Should we re-pot them? If yes, how do we re-pot them from the shells?
3)How do we know whether the orchids are getting enough water and well fertilized?
4)Is it true that orchids get the best sunlight from the eastern sun?
5)Can they grow well under normal florescent lights?
6)Is it possible to place orchids in the bathroom?
Thanks for answering my questions patiently.
Katie
Hi Katie,
1) The orchid leaves will exhibit signs of light stress (e.g. signs of purpling/yellowing initially and dark spots due to leave burns later on) if sunlight is excessive.
2) It is not necessary to re-pot the orchids unless it overgrows the shell. For repotting, kindly refer to http://www.tohgarden.com/orchid-care/dendrobium/ under the repotting section. You can use a small to medium size pot for repotting miniature instead of the usual large ones.
3) The pseudobulbs will be turgid, smooth and fat if they are receiving enough water, nutrients and sunlight. Older pseudobulbs that have finished flowering can show signs of wrinkling, this is fine but younger pseudobulbs should not have these signs.
4) I’m unsure about this as our orchids are exposed to all directions of sunlight in our nursery. I believe this is true to certain extent though as the morning sun (eastern sun) is not as scorching as the afternoon sun as the morning environment is cooler, so there’s lesser chances for heat stress for the same amount of light introduced to the plant.
5) It is possible to grow orchids under normal florescent light but do note that the amount of light that the plant receives from a normal florescent light is likely to be much lesser than that of sunlight.
6) This is subjective, depending on what type of orchids you wish to place in the bathroom. It must be able to tolerate a good amount of moisture. The miniature Dendrobium‘s probably fine but you will have to keep their roots dry with good air movement and the amount of lighting has to be minimally sufficient.
silverelf
I have a new Dendrobium orchid but it looks nothing like anything I can find on the Internet. It has one tall fat stem and leaves and flowers grow directly out of this stem all the way up the stem.
My questions are – do I remove the flowers when they start going over and how do I treat the plant when it has finished flowering?
Will a new stem grow or more flowers and leaves from the current stem?
Hello Joy,
Its likely that you are not growing the tropical type of Dendrobium that we are growing. The orchid that you describe is similar to that of Dendrobium nobile type. These are slightly more temperate orchid. Jiro Yamamoto is a famous hybridizer of numerous nobile type hybrids since the 1950s. You may wish to google for Yamamoto Dendrobium to learn more about this type of orchid.
To answer your question, yes new keikis will grow from the current stem when summer and spring arrives. Keikis are more likely to be reproduced when the climate is hot. If the plant experiences cold nights, it will tend to flower rather than produce new keikis. This is of course also dependent on how healthy the plant is. If the plant is stressed, it may still produced shoots instead of flowers or produce lesser flowers.
silverelf