That is usually the first question I get asked when people see the options available for repotting orchids. And my answer is: Yes. Yes, really. I’m sorry but it is necessary. Yes you have to. Do you want your orchids to survive?
It always next moves to the question on why there are so many choices. My simple answer is why are there so many different food choices? We have our favourites, and orchids have their favourites too.
Orchids grow naturally in trees, on rocks, in sand, in jungles on the forest floor and even in the Artic. In fact, orchids grow everywhere, other than in the Antarctic. So now you get the picture – orchids grow everywhere, and everywhere is not always the same. It can be hot, dry, cold, wet, humid, windy, sheltered, frosty – in essence, everything that your windowsill isn’t.
When we pot up orchids, we are actually trying to mimic the natural habitat of orchids in a pot. It is not always easy as you can imagine. The options are there to adjust the conditions in the pot so that they are closer to natural surroundings. This is critically important for species (plants as they are found in nature), but hybrids (man made crosses not found in nature) are generally more forgiving.
There are many options available, from sphagnum moss (from either Chile or New Zealand), fir bark, coconut husk (coir), tree fern, cork bark, charcoal, perlite and sponge rock, humus, vermiculite, hydroponic media and countless others up to chopped automotive tires. As you can imagine, each one has its on benefits and drawbacks.
Typically, most orchids at home are in one of two options – sphagnum moss and fir bark mixes. The moss will hold the most water, while large chunk bark mixes will hold the least (that is if we exclude chopped tires!) As you can image, the growing conditions in Thailand are very different from the windowsill over your kitchen sink in Scarborough. We won’t worry about what might work in Thailand, but just what works here. No matter what you choose, or what the grower you bought your plant from chose, you will have to replace it, usually within two years. Whatever you pot in the pot to mimic the natural conditions, will rot in the pot over time: you do not have the luxury of having nature replace everything automatically for you.
After having the conversation about why you need to repot, it is my turn to start asking questions – what kind of orchid is it, how big is it, what is it in now? This is where you need to be able to tell me what you have, because all orchids are not equal when it comes to what is in the pot. You really need to know the name of the plant if you are going to ask for help with it.
Your common choices are Phalaenopsis, Cattleya, Oncidium, Paphiopedilum. The potting techniques are almost the same, but you use different potting media for different plants.
Before you start to repot, you need to put your kit together. You will need your orchid, which has been well watered, newspaper, the new media you will be using, a fresh pot, a sterile blade and a pencil. You will need a pot as well (duh!!) how big you ask? Well it is big enough for the roots you have; typically you use the same size pot on a mature plant or one size up for a plant that is growing in size or that you want to maintain as a large specimen.
Now lets repot!!
Lets start with the most common, the Phalaenopsis, or sometimes called Doritenopsis. They are also called the Moth Orchid by some. You can treat small Phalaenopsis and Cattleyas the same way, and large Cattleyas and Phalaenopsis similarly as well; they just prefer different stuff in the pot depending on how big they are.
You need to water your orchid well; this will allow the old mix to be more readily removed.
We need to determine what you have chosen to use to repot your orchid with. If the plant is in a pot 6” or larger you will want to use a bark based mix with larger chunks. I use one which is bar, sponge rock and charcoal. In pots 4” or smaller, I use New Zealand Sphagnum moss. For 5” pots you can use either, depending on whether or not you have a heavy hand with watering. The more you water the better bark will work for you. I have a very light hand with watering, so moss overall works better for me.
Lets first do a small one, so we will be using New Zealand sphagnum. You need to soak the moss for about 20 minutes, squeeze out the excess water, and then fluff up the moss. It will then be just damp.
Now that you have made the decision to repot, you have your media and other supplies ready and your plant all watered you are ready to start.
Step one is to spread out the newspaper where you are going to be working. It will make cleanup easier.
Step two is to remove the plant from the pot, carefully put aside the tag (you will need it later) and start to carefully remove the old media from the roots. You want to gently do this so as to not damage the roots too badly. When they are fairly clean, gently rinse them and put the plant aside. If you have any dead roots (they squish like a wet sponge) you can remove them with a sterile blade to prevent transferring infections. Good roots are hard and do not squish. Now you can roll up the newspaper and dispose of the old mix into your compost bin or green bin for organics.
Step three is the easy part. Take a small ball of moss, and place it in your hand. Put the plant on top of the moss ball allowing the roots to hang down. Gently wrap the roots around the ball you have made. Now take more of the moss you have and pack it around the roots covering the root wrapped ball completely Finally take your ball and place it in the new pot so that it is about ½” (1 cm) below the rim of the pot. Add a bit more moss if necessary so the plant does not wobble in the pot.
Step four is to take your label, and add to the back-side of it the date. This will help you keep track of when you repotted, and when you will need to do it next.
AND NOW YOU’RE DONE! Easy eh!
For this bit, we are working with a larger Cattleya or Phalaenopsis; that means in a pot 5” or bigger. Now for a Cattleya, we also have to question what size the pot is, but for Cattleyas I find that 4” pots and smaller are better with New Zealand sphagnum, and those pots larger need the bark mix. If you have a small plant, then follow the instructions for Phalaenopsis. These are for the large plants.
As with the Phalaenopsis, get all of your materials together and water your plant well. For these larger plants you will be using the bark mix to repot; it is important that you SOAK THE MIX OVERNIGHT prior to using it. The bark takes much longer to wet properly. If it is not thoroughly wet, you will end up starving your orchid for water. This step cannot be rushed or overlooked. If you forget, or do not have enough, do it tomorrow!
Step one is to spread out your newspaper!
For step two, again you need to remove the plant from the pot as gently as possible. If you have roots growing through slits in the pot , it is helpful to cut the pot apart to save the roots. Remember the dead roots are squishy and the good ones are firm. If you find you need to remove many roots – and remember we all kill roots – do so with a sterile blade; you do not want to transmit disease from one plant to another accidentally. Be gentle removing particles of the old mixture: remove as much as you can without seriously damaging the remaining roots. Remember, we grow roots with a plant attached; without roots there will be no flowers! There is another half step when repotting a Cattleya which is not involved with Phalaenopsis. Cattleyas are sympodial orchids, that is they grow by marching ACROSS the pot, not constantly upwards as Phalaenopsis do. This means that as the Cattleya matures, the older growths (pseudobulbs) will loose leaves, yellow and dry off. When this happens, we do not want them in the new pot. These old back growths can be removed with a sterile blade, and you can dust the cut with powdered cinnamon. If you are dividing up a big Cattleya(putting several pieces into separate pots), make sure you leave at least 4 or 5 growths together for each pot: too few and the plant will take a long time to recover and start flowering again. As with the Phalaenopsis, now roll up the newspaper and toss out all the old mix, rotted roots and any removed growths..
Step three is a little different when you are using a bark mix. At this point, I typically get out a tray; the mix will drip water all over and slowly drain out of the pot. If you don’t mind constantly washing your counters then you can skip the tray. To start with, place some of the mix into the bottom of the pot.
For a large Phalaenopsis, put the plant into the pot and hold it so that the lowest leaves are about ½” below the edge of the pot: I find it helps at times to rotate the pot so that the roots spiral allowing you to get the plant to the right level. Now take one handful of mix at a time and put it in the pot over the roots and wiggle the pot to settle it in. Slowly work you way around the pot, handful by handful until it is full. Push down firmly to compact it all in so the plant does not move.
For a larger Cattleya, we again start with some mix in the bottom of the pot. Again, place the plant in the pot, and twist if necessary to get all the LIVING roots inside. Now the tricky part; you need to place the oldest growth up against the side of the pot. Cattleyas grow across the pot, so we want to provide the most room possible. Holding this old growth to the side, and at a level so that the rhizome (the horizontal bit between the growths) is about ½” below the rim, start adding handfuls of mix and jiggling the pot to settle it in. Firmly press it down to hold everything in place when the pot is full.
Step four adds an extra bit: water the pot well, and you will flush out the dusty particles which are inevitable in a mix. Add the date you repotted to the back of the label and return it to the pot.
And now you have done a Cattleya!!