Using pure sphagnum moss as a growing medium is becoming increasingly popular so let’s see if it’s worth the hype.
For starters, it is significantly more sustainable than peat moss so that’s a massive win. Peat moss is the dead plant material harvested from the under-layer of boggy wetlands. The ‘moss’ in peat moss is the once alive sphagnum it originated from. Most commonly, Sphagnum cymbifolium – peat moss grows at roughly once inch every 15-25 years and takes centuries to accumulate. Whereas sphagnum moss can either refer to the live moss many people grow, or to the cut, dried, and processed new growth that we can find in bags at many nurseries or online. This only takes a couple of years to grow.
Growing in sphagnum
Sphagnum is considered a great growing medium because of its ability to retain moisture–retaining roughly 18x its dry weight in water. Epiphytic- (plants that grow on another plant without being parasitic) and lithophytic (plants that grow on bare stone or rock) plants need a fair amount of air to get to their roots whilst a fair amount of moisture remains around the roots, which makes this an ideal medium for them. Epiphytic and lithophytic plants include Philodendron, Monstera, Anthurium, various orchids – basically most of your indoor plants.
Dried sphagnum retains its structure, and this is what makes it ideal for our plants. It’s important to note the structure will start to break down and decompose after some time. After having grown a plant in the medium for around 8-12 months, you may start running into some additional challenges. After that point, the sphagnum’s structure starts breaking down, turning the root environment acidic – the sphagnum also tends to retain more moisture at this point which could lead to root rot, if left unchecked.
Types of sphagnum & where to find them?
You’ll often find sphagnum moss dehydrated and in bags, either at a local nursery or online. Personally I think this is ideal because it is easy to store and you don’t have to worry about it dying on you. I tend to gravitate towards Culterra’s Chilean Sphagnum, mostly because it is easy to find at my local nursery. However, if you can’t find it at a local nursery, there are so many options online, like Bonsai Tree. They offer 2L and 5L bags alongside a bulk purchase option. You can even find sphagnum at Woolies! If you would rather support small local businesses, I would highly recommend buying from Bonsai Tree or Cultivo Carnivores.
I do love live sphagnum though. There is just something so fascinating about growing it and it’s surprisingly easy to grow. You can quite literally grow it from the dried moss because some pieces still retain spores and under the right conditions they will start sprouting. It took me about three to four months to go from dried moss to live sphagnum, as in the photos below. If you do not want to wait this long, you can find live sphagnum online at Cultivo Carnivores.
Propagating in sphagnum
Propagating in sphagnum is my preferred method of propagation because it’s never failed me and I find it to be very simple and easy.
STEP 1: Removing all debris and soaking the sphagnum
Start by removing all of the loose twigs and debris that you might find in the sphagnum to avoid the root environment becoming too acidic too fast (this is due to the structure breaking down into a sawdust-like substance, as it compacts it becomes acidic because it is decomposing). Then, soak the sphagnum in a separate vessel – the reason you do this is because the Sphagnum is incredibly dehydrated and brittle and it is rather difficult trying to saturate it in a pot.
STEP 2: Filling your pot/propagation vessel
Start filling your pot, or whichever propagation vessel you are using, quite loosely with your wet moss. It is very important to not compact the moss, but rather leave slight air pockets. In my experience, this ensures that enough oxygen is traveling to the newly developing roots and helps them grow significantly faster.
STEP 3: Planting your cutting
Place the node of your cutting – where the petiole (stem of the leaf) meets the stem of the plant – underneath the sphagnum. If you are planting a cutting from an aroid, a good indicator to find the node is to look for where the aerial roots are (little roots growing from the stem of the plant), and plant that bit underneath the sphagnum.
STEP 4: Keep your new cutting moist
Now that you’ve planted your new cutting, keep it moist and in a warm and well-lit position. An easy way to spot if your propagations need a watering, is when the sphagnum changes colour from a deep caramel to a very light tan colour. In a few weeks your cutting will have turned into a fully established plant; how exciting!
As the sphagnum further starts to decompose, it breaks down into what is essentially peat. The decomposed pieces of sphagnum will start to compact, closing off any additional air pockets around the roots, retaining more moisture than necessary – this can lead to root rot. The only surefire way to prevent having to deal with these issues is by repotting far more frequently than you would if you were using a more traditional soil mix. Alternatively you can use some additives, like orchid bark, horticultural charcoal, perlite etc. to create more air pockets in the sphagnum and slow down the compaction, however, you will need to water a little more frequently when using this method.
With that which could go wrong being said, do I believe it to be a terrible medium? Absolutely not. From personal experience, it is one of the most ideal mediums to grow various plants, especially Anthuriums. Some of my happiest Anthuriums have been growing in sphagnum moss as the main medium for well over a year, touching on two, and they are thriving. It is all about keeping an eye on them and moving quickly when you start seeing changes in water retention or the overall health of the plant. Why not give it a try? If you have any questions or would like to share your experience, drop a line in the comments below.