Alpine Garden Society

01386 554790
Back to List of Entries for Wisley's Alpine Diary

Go to bottom

You can add your comments on the content of this diary entry by starting a discussion, but you need to login first

Wisley's Alpine Diary

This entry: 15 January 2009 by Paul Cumbleton

Log 39 - Repotting Pleiones

Wisley's Alpine Log

By Paul Cumbleton

Log 39…15 January 2009


As always at this time of year, I am at home undertaking the big job of repotting my Pleione collection. So this week’s log is a step by step guide to how I do this and it ends with some fishy surprises….


1. Unpotting

I unpot the entire collection before potting up again, the reasons for which will shortly become apparent. First I remove the clump of pseudobulbs from the pot and then pull each one in turn out of the clump. Each pseudobulb lasts just a year, replacing itself with one or more new ones each year. You can see in the first picture that the old (now shrivelled) pseudobulb in the middle has made two new ones. The roots too are only annual and at this time of year are all dead. They can be trimmed off with scissors.

You see that I don’t remove the entire old root, but leave 2 or 3cm length intact. This just gives a bit of something to help anchor the pseudobulbs in the new compost when replanting. This next picture shows how much is left after trimming:

Next I pull apart the two new bulbs and then the old, shrivelled bulb from last season can be removed and thrown away. It comes away easily with a gentle tug.

Although not essential I also take off the brown papery tunic that covers parts of each pseudobulb. This is a good time to look carefully at each pseudobulb, checking for any signs of pests or diseases.


2.  Storage


Once all the bulbs from a pot have been done, I store them in paper bags, remembering to put the pot label inside the bag too. The bags are put into trays until I am ready for potting up again. You can get a lot of bags in a tray – stored in this way they take up little space and they can easily be moved around.

I do this for a couple of reasons. Firstly, I have two greenhouses with Pleiones and stored in this way I can move them all into one house which means I only need to heat one instead of two for a while, thus saving on costs. (I keep the Pleione houses just frost free, about 5 Centigrade, through the winter). Secondly, while one house is empty I can give the other a thorough clean out and then a spray down with a horticultural disinfectant, hoping that I can start the year ‘clean’. I next move all the trays into this clean house while I repeat the cleaning process in the second house.


 During the unpotting, I mark the bags of any varieties that flower early in the year and these will be the first ones to get potted up again. Other than any winter-flowering hybrids, it is invariably Pleione humilis that is the first to flower for me – one is in flower right now – so this species is always the first to get repotted.

3. Potting Mix


I’ve tried so many mixes over the years. The one I use now is very simple, just bark and moss. Buying proper orchid bark can be quite expensive. As I repot my plants every year, I don’t need the bark to last more than one season and I have found that a cheaper alternative is fine. I use what is called potting bark, made by Melcourt:

You can see from the list on the bag that they produce a range of materials; the potting bark is the first on the list. Here is what it looks like out of the bag:

For smaller pseudobulbs or seedlings, this is a little too coarse, so for these I do buy a proper orchid bark, getting the “fine” grade that Ratcliffe Orchids sell. You can see this here on the right and compare it to the potting bark above. It is an ideal size…but it costs over twice the price of the potting bark!

As I mentioned, the other ingredient is moss. I use the dried Sphagnum moss that comes from New Zealand. This is the species Sphagnum cristatum which grows quickly and is harvested sustainably. You can read more about this aspect at the producer’s website, on this page:


As I use a lot, I buy the 3Kg bales which come compressed like this:

I pull apart the compressed strands and first soak them in a bucket of water. I find when I try to mix the moss with the bark, the strands are too long and don’t mix in well, always wanting to separate out, so they need to be chopped to a shorter length. It is easier to do this when they are damp. I take a large handful of the wet moss, squeeze out the excess water so the moss is damp rather than wet and then use the finely serrated edge of a bread knife to cut it with. This is easier and quicker than using scissors. Once chopped, I make up the mix. I use 3 parts bark to 2 parts moss, by volume, and it ends up looking like this:

I find this mix stimulates strong root growth, as you can see here where I have just tipped out a pot from last season ready for unpotting:

4. Potting up


To pot again, I fill a pot with compost to within about a centimetre of the top and place the pseudobulbs on top of this. You can place them quite close to each other to get a good display of flowers:

Finally I top up using just the potting bark to cover the bulbs to roughly half their depth, leaving the noses sticking out of the compost:

Once potted, it remains but to put them back in the greenhouse where the bench quickly starts filling up with all the newly potted collection. Mission accomplished!

Those with a good memory will remember the promise of something fishy… well stay with me; it’s an excuse to end with some colour!


Where we live, my partner is involved in a wholesale business supplying tropical fish to the pet trade. Here is just one corner of the setup which has hundreds of tanks:

They breed on site many of the fish that they supply. Here for example is a tank-full of baby Pearl Gouramis (Trichogaster leeri) which are 4 weeks after hatching…..

…… while these are near-fully-grown Zebra Danios (Danio rerio):

Ok, these aren’t plants and these particular ones are not even especially colourful. However, tropical fish require warmth so the fish houses are all well heated. And all that water creates high humidity. Now let me think…warmth and humidity….mmmm, well, the business may call this a fish house, but I call it………..Phalaenopsis Heaven! We have commandeered a wall and used it for a small collection:

They absolutely love it in here; the conditions are so perfect for them they almost grow themselves. So here finally is some colour to end with:

Hope you enjoyed this little glimpse of home. Back to Wisley next time.

Go to top
Back to List of Entries for Wisley's Alpine Diary

You can add your comments on the content of this diary entry by starting a discussion, but you need to login first