10 Reasons why Sphagnum Moss is good for Potting Orchids
Is sphagnum moss good for your orchid? When repotting, sphagnum moss for orchids is essential in your orchid potting medium. Can you use sphagnum for every type of orchid? To the contrary of most things about orchids, where the typical answer is, “it depends,” you can
use sphagnum moss in every type
of orchid media. Sphagnum moss is an excellent medium since it allows air to circulate freely around the roots of the orchid. Sphagnum's moisture-absorbing qualities ensure proper irrigation for your orchid and it binds ammonium, slowing down the decomposition caused by microorganisms. All these promote a healthier orchid life.
This isn’t everything sphagnum moss does. To understand sphagnum moss for orchids, which I've used in every single orchid design so far, let’s take a moss tour:
starting by its structure,
talking about the different qualities of moss on the market,
and in the end, the benefits for your orchid (which is the most important part, right?)
In this article, I'll answer the top 10 questions about sphagnum, listing the pros and cons of its use in potting media.
1) What is Sphagnum Moss for Orchids?
Sphagnum moss is a tiny plant which comes in a variety of colors (green, pink, and red) that thrives well on little soil with poor nutrient value. This is why it can excel in terrariums and places that don't have adequate nutrition from the soil, like your orchid pot.
You can usually find moss growing on a dead tree. Unlike popular belief, sphagnum moss is not a parasitic plant, which caused the death of the tree. Since there are poor nutrients in the tree bark, the sphagnum moss attaches to it.
You don’t need to worry about the bad omen, because there is no bad omen associated with sphagnum moss or the death of a plant. Change your focus: see moss as an indicator that the plant—or in this case, a tree—has lived its better years.
2) Why is Sphagnum Moss Important to My Orchid?
Image credit: Orchideria © 2020.
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The water-retaining property is sphagnum moss’ most advantageous qualities.
If you place water at the end or tip of one stand of sphagnum moss, water will “travel” through the highly vasculated system of the plant, reaching the other side.
You don’t have to water as much or with greater quantities, because sphagnum moss will retain the water up to 20 times it’s normal, dry weight. Slowly releasing the water in time, “moss” creates a natural watering environment that propagates humidity and nourishment.
The internal structure of sphagnum moss is very porous. I like to think of it as a minuscule circulatory system, with veins, arteries, venules, and capillaries. Of course, this isn’t quite the case, but you get the idea. Water can circulate through the moss to hydrate all of its extension.
No need to ice your orchid, the infamous drip system. Besides ice cubes being awful to the roots, they cause blackened spots on the leaves and petals. Ice water is extremely harmful to the velamen (the grayish-green coating that protects the roots), damaging its future potential to absorb water.
Every time you think about watering your orchid with ice cubes, please take an ice-cold shower yourself, then leave a comment below on how that felt. :)
3) What do you look for in a good quality Sphagnum moss?
Moss comes in different qualities, called grades. Some producers give moss letter grades, like AAA, or star grades, like 5 stars. If it is long, thick, and dense, its absorption properties are higher, thus it is a higher quality moss.
The longer the strand, the better it is to wrap around each individual orchid root. Also, the denser the strand, the more water it will absorb. In newbie terms, this is the “fluffiness” of the strand.
Think of a sponge. The thicker the sponge, the more it absorbs. Some orchid growers pack their pots densely with sphagnum moss, thinking that this will provide more water for their orchid. But that’s not how moss works. If you squish the sponge tightly then try to water it, the less water will it be able to absorb.
It you soak the open sponge, the more it will soak in—same with sphagnum moss for orchids.
We won’t mention name brands, but we will call out some countries that are known for excellent quality sphagnum moss. New Zealand Moss is one that always comes up in the recommendations—always as in every single article that we researched. It by far outranks all the others, with an AAA.
Sphagnum Cristatum is also the highest quality and was nominated for the length of its strands, facilitating the repotting process. Surprise—it grows in New Zealand, too.
The third recommendation is the S. Subnitens, also from New Zealand. (See a pattern forming?)
The fourth five-star recommendation we saw a lot was a species from Chile, the S. Magellanicum (or called Magellanic bog moss.) It has shorter strands and fibers, but was leafier, and denser.
Wisconsin and Canada also have excellent sphagnum moss growth.
4) Can I use only sphagnum moss as a medium?
Yes, you can use it by itself as a medium. This is especially good for orchids that need urgent tending love, or are deathly sick. Orchids that have no roots or have been severely damaged are also an excellent choice for a medium with only moss. Sphagnum will not be abrasive to new roots, as perlite or lava rocks will, and with constant humidity, this moss is perfect.
Just make sure that you don’t compact the sphagnum too densely in the pot, providing for proper air circulation and, as mentioned above, better water absorption.
Orchids that thrive in more humid climates are Bulbophalliums, Masdevalias, Jewel Orchids, and Dendochilums. In their potting mix, sphagnum is essential.
5) How do I repot with sphagnum moss?
When repotting, first soak the moss in water anywhere from 30 minutes to overnight.
Once soaked, squeeze the moss to rid of extremely wet medium. Soak then squeeze? Isn’t that counterproductive? No.
The soaking is for the moss to first absorb the water, since it probably has been sitting in a plastic sack for months on a supermarket shelf, waiting to be useful again in life.
Anyway, it has been in low humidity environments for a long time, and this initial soak will aid in fluffing up the strands. But you don’t want all this excess water in your roots, if not root rot will certainly occur.
Squeeze the excess out, leaving a damp medium to work with.
Wrap the long stands or sphagnum loosely around each root. Remember, this should be well-spaced out, leaving lots of air and providing space for the roots to grow. Don’t’ wrap them tightly.
Grab a big wad of moss and make a ball, inserting it under the middle of the orchid. Think of the orchid roots like a baseball glove and the moss, the actual baseball, nested inside the roots.
Place the orchid inside the pot, which should have sufficient space on the outside of the root “glove”, preferably an inch or two. Gently push sphagnum moss for orchids in between the roots and the sides of the pot, making sure not to compact it.
6) How long does sphagnum moss last?
This depends entirely on the quality of moss you buy. Sphagnum moss lasts anywhere from 6 months to 5 years. If you acquire a higher quality sphagnum, then you’ll need to repot in between 2 to 5 years. With a lower quality moss, you can expect the medium to degrade in less 6 months.
Is there any time you'd want to use lesser grade sphagnum moss? Yep. For curing sick orchids, sphagnum is a treatment from the heavens and should be repotted as quick as possible. If you have young seedlings, or keikis, then looking at a lesser grade
sphagnum moss might also work. (I say this, but my fingers are protesting
as I type.)
Always use the best quality moss if you can.
Maybe curing a sick orchid with sphag and bag is what you are aiming for, and can then repot them in a better quality medium when they recover, in less than 6 months. But for the healthy, mature orchids, they will hate being repotted this soon.
The less orchids have to be handled, touched, interacted with, and make social appearances outside their pot, the better they are—happier, too.
Young orchids will require a small pot, and as they grow, you will need to transfer them into a coarser potting medium and larger pot.
7) Can you reuse sphagnum moss?
To the most part, no. If you do research on this specific topic, you will see that most the people who are asking are builders of aquariums and vivariums. The moss they purchase is alive. They have special containers to grow and propagate moss to use in their terrariums. So their answer will be, "Yes, you can reuse moss."
If you take their specific answers for vivariums and transfer them into an “orchid background and setting”, you'll get the incorrect answer.
Sphagnum moss sold buy garden centers and supermarkets is not the same as used in aquariums.
The whole point of repotting is that you have to throw away the moss that has decomposed to a certain degree and add new medium. This provides decent air circulation, the right pH, a clean mix in which the orchid roots can grow, and proper water retention occurs.
After 6 months (for lesser grade moss) the circulation takes a hit and sphagnum moss loses its best quality. Toss it, repot, and never look back.
8) Why do some orchid enthusiasts hate Sphagnum moss?
Sphagnum moss does have its “cons.”
Refusing to work with sphagnum moss for orchids comes down to its number one quality: water retention. Most people who have used sphagnum and detest it, usually has to do with root rot.
A “serial over-waterer” will not do well with sphagnum moss. Since the pores retain water and slowly release it into the medium, over-watering will quickly promote root decay.
There is a famous quote about orchids: neglect them, and they’ll love you. Well, that's just completely toxic... But, what this phrase means is that an orchid would prefer to not have that much water and dry out from time to time, then to be watered everyday and suffocate, drowning inside its humid pot.
If you forget the poor little plant for a day or two, it will be happier than if you over water it every day, constantly drenching the poor dude.
Of course, neither is preferred—these are just examples.
Another problem in the cons of using sphagnum moss is its low pH, leaking out acidity into the medium. Sphagnum is neutral when bought, but can become toxic (over time). So toxic, that it can create dentures in cement. Because of the acidity, your potting medium needs to be thoroughly flushed out once a month.
Flushing out is also good to eliminate the salt retention.
As sphagnum moss for orchids will retain the nutrients and keep them for some time before releasing them into the medium again, you'll need to be very careful of how much fertilizer you add with sphagnum. Dilute it by half the recommended dose.
Even when diluted, a salt build-up can occur on the top of the medium. It can also build up with any water you use that isn’t rain water, distilled water, or reverse osmosis water.
Once a month, take the entire pot to the sink and let water rinse the medium out thoroughly, more than a normal watering. But be careful to not compact the sphagnum when watering, because it can compact easily.
Which brings me to another excuse that I hear a lot: Sphagnum compacts too quickly.
It might not be the quality of the sphagnum that is brought under question, but the watering method. Irrigating with a straight jet of water, turned on high, powerfully crushing down on the medium causes sphagnum to compact.
Many people don’t realize this when they take their orchids to the sink. Drizzle, my green thumbed friends, drizzle. Don’t open the spout to full force. Sphagnum compacts under pressure, so let’s not add extra compacting with the force of a waterfall.
Another tip of how not to compact sphagnum is to use 1 to 2 inches of LECA in the bottom of a pot. When watering, place the pot in a pan where the water covers just the pebbles, and nothing more.
LECA, with its water absorbing properties, will retain the water, transferring it to the sphagnum, and sphagnum…with its water conducing properties…will transfer the water within the pot evenly.
This method is a bit more time consuming, but it works.
9) What else is sphagnum moss good for?
Top dressings are perfect for sphagnum moss. To protect new roots before they actually reach the medium, (even aerial roots, too) you can use a thin layer of sphagnum moss to prevent them from drying out.
To aid in maintaining these roots humid and with some nutrients, top dressings come in handy. Not applying the top layer too thick, which would hinder air circulation, lay a fine layer (no more than a few strands) of moss over the roots. When the roots the reach the medium, you can remove the top dressing.
Paphiopedilums are another example that aid from a thin layer of top dressing, but in this example, they are mostly aerial roots.
If you work in an office or home-study that has extremely low humidity, then a top dressing is more than welcome to provide your orchids with extra root care. Even though they are aerial roots, the thin layer of sphagnum will provide the protection from the hostile work environment.
Is work a hostile environment? I need to rephrase that. What we meant was: protection from the extremely low humidity-environment.
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10) Is there a difference between peat moss and sphagnum moss?
Sphagnum moss for orchids is a specific type of peat moss that grows freely in nature.
There are anywhere between 200 and 300 species of different types of mosses, and sphagnum is just one.
You might come across a bag of sphagnum peat moss and wonder if it is the same thing. Quick answer: no. They both start off as the same plant, growing in the same conditions. Sphagnum moss is alive when it is harvested, then thoroughly dried out, packed, and sold on the market.
Peat moss is what is under the sphagnum moss, and is not entirely sphagnum. Peat is composed of old dead plants, leaves, twigs, and even dead insects. Sphagnum is the majority, but not the only plant that comes in peat moss.
Dead material pressured into a compact wad of moss is the best definition for peat moss. This layer has been dead for quite a while, but nothing hinders new moss from growing over it. After some years, the old layer dies…and again, another new layer of sphagnum moss grows. This multi-layering forms the compacted peat moss.
As in quality, sphagnum moss is preferred 100% over peat moss.
Peat moss doesn't retain the same moisture and usually is cut up into fine, smaller pieces. We say usually because you can buy sphagnum moss in cut up pieces which is a total waste of perfect sphagnum moss, in my opinion.
pH also comes into count. Sphagnum moss for orchids is generally natural when purchased, only leaving trace amounts of acidity (4.5 to 5.5) after it starts to decompose. Peat moss is already a lower pH when bought and contains multiple tannins, bringing your orchid closer to a pH of 2. If your orchid does not like an acidic medium, peat is definitely not your choice potting mix.
It might be cheaper, but it is sold in a compacted brick. Not all the materials in peat moss will promote the water retaining properties that sphagnum moss will. That means that you're potting your orchid with possibly dead twigs, bugs, leaves, and other materials that have no other use but to compact your potting mix and promote decay. Use sphagnum moss without the peat moss, and your orchid will thank you.
If you're low on Sphagnum Moss, check out a few brands that can be found on Amazon. All the links below are Affiliate Links, so I do get a small commission for recommending them, with no extra cost to you.
If you're not quite ready to start repotting an orchid, how about reading some of our other articles, like adding charcoal
to the potting medium, maintaining proper humidity
, or watering mounted orchids
If this information was of any help or clarified any doubts you had, please mention so in the comments. I love to interact with other orchid enthusiasts, and we all can share from our experiences. Share this page with a friend who has an orchid, comment, or just give me a thumbs-up in the comments below. I'd sure appreciate it. :)