Learn to Repot your orchid by looking at its roots!
So it's time to repot your favorite orchid, eh? If you've never done it and are anything like me, your thoughts are probably going along the lines of: "Oh crud, I hope I don't kill this thing!" And that's before you've unpotted your beauty to see the oddity of a root system your 'baby' lives on!
Hopefully this little pictorial will help to alleviate some of that stress.
I'm assuming you've gone out and gotten your supplies... you didn't? Well go do that! Orchid potting mix that's appropriate for your orchid (don't use every day potting soil) is a must, and you might want to buy a new pot while you're out - either next size up if your repotting due to crowding, or same size if not.
Make sure you're using the right size and type of mix for your orchid & growth culture. There are lots of great posts throughout the forum
regarding culture and mixes if you have questions about what is right for you and your type of orchid. If you're using bark or sphagnum, take some of that mix and soak it in water for a few hours or even overnight, if you have the time.
Now you want to make sure you have a good, clean space to work with. Lay out some news paper (or a plastic grocery sack works, too) to catch your old media on. Newspaper also helps to make sure you don't give your plants any vener--err.. viral diseases. If you're repotting multiple plants, use new work-space protection for each one. I know my photos show me working on a bare counter top, but I also sterilized that with bleach-water.
Step one is getting your plant from the pot. Sometimes this is easier said than done. Personally, I find taking a firm-but-gentle hold of my plant as close as I can get to the media then using a gentle wiggling motion with the pot sideways (or upside-down for the stubborn ones) seems to help. If you have a plastic pot, you can gently squeeze the sides to help work things out. If you have roots waving at you from the bottom, I have had pretty good luck pushing those back through the holes as I ease the plant out of the pot. All else failing - you can either cut away a plastic pot or tap a hammer around a ceramic/clay pot.. You lose a pot, but gain a healthier orchid. (And isn't that what this is all about?)
Ok. Hard part is done... Wait, is it? Well... we hope so. Now, you should have something that looks a little like this. Here's a photo of my Bc Hamana Soft freshly pulled from the pot... Putting it on the carpet is probably not the best of ideas, but...
and the icky mess of media that was left over.
And here's what our Cattleya's roots look like after a good washing... (I recommend carefully rinsing all old media off the roots to prevent future rot troubles.)
Or, maybe you have a Beallara
Want to see what Dendrobium
roots look like? (in a pot, but all the same) They remind me of Phalaenopsis roots....
(thanks, Mom for the pic)
roots (I found a slug up in there, too! Yuck!)
- still in media because this one was in bloom (just checking for pests)
< Note on Roots: Roots on paph & phrag type also seem to have little hairs on them! I always try to avoid scrubbing these off. >
Ok, on with the show. I'll use my poor Cattleya as an example for what to clear away as 'bad' roots. You'll want to cut away bad roots with either some sterilized garden shears or a good old fashioned razor blade.
Here's what the icky roots look like (after they've been subjected to root-rot conditions). Notice how they're all black? If you feel them, the velamen (the thick coat on top) is probably soft or might even slip right off that skinny thread-thing in the center (that's the real root), which is also usually black or dark brown.
You'll want to cut these bad roots off as close to the healthy parts as possible. Or all the way back to the top if the whole thing is done for.
So, what do good roots look like if those are the bad ones? Well, good roots are firm to the touch covered with a white or tan velamen layer. They look a bit like this...
Alright, so now that you have an idea of what bad and good roots look like, get to work!
This is what I was left with after all my trimming was done. I left some of the brown-spotted roots on because they weren't quite dead and I'm an optimistic soul....
Now the nerve-racking bit is over with! So now, lets take our cleaned-up orchid and get it into a new home! To ensure drainage, I like to put a few non-degradable packing peanuts in the bottom of my pots, but this isn't necessary. A few larger bark chips at the bottom will do. Once you have a layer of mix under where your orchid will be, suspend your orchid in the pot with the oldest growth closest to the side so there's room to grow... You can use your hand or suspend your plant with a stick or pencil, which will leave both your hands free.
You have a phalaenopsis or some other orchid that grows upward from the center, you say? Well that's different. Try to keep your orchid centered in the pot, in that case. This technique will also work if you have something like an overgrown oncidium that wants to grow new bulbs from the center of the plant, too. Try to leave some room around the sides so it can spread out.
No matter what direction your orchid grows, usually you'll want the top of the roots about 1/2 inch or 1 cm below the edge of the pot. Now that we've established where you're placing your plant, slowly sprinkle your mix in around the roots, tapping the side of the pot between sprinklings helps to settle the media between your roots as you go. Settling the media around the roots will also help to support your orchid and keep it upright in the pot. Once the pot is full with your mix, tap the bottom of your pot on the work bench to help settle your plant and water it!
Guess what? You're done! It's over! You've officially repotted your orchid. That wasn't so bad now, was it?
Learn more about repotting orchids in the OrchidTalk Orchid Forum!