Repotting

Different orchids require different potting treatments. (Check individual plants in the “Orchids” tab.)  But some of the practices are used more frequently than others. There are orchids that are wired bare-rooted to slabs of bark. There are orchids that hang bare rooted in decorative wood baskets where the roots trail out through the bars of wood and hang down in the air. Both of these styles survive mostly on the humidity in the air and rain (in nature – misting and/or watering when in captivity.) There are some orchids that grow in actual soil. I own one and will discuss it here later. There are orchids that seem to do best in Sphagnum moss.


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The most common potting material, however, is chips of bark, either pure bark, or mixed with bits of volcanic stone, pumice, possibly styrofoam chips or beads, small pieces of charcoal, etc. The intent here is to provide a medium that can be moistened thoroughly but will also allow a lot of air circulation around the roots and gradual drying of the medium to a greater or lessor extent before it is watered again. I’ve used both the pure bark chips as well as bark with all the additives. I haven’t ever seen much difference although since some of the additives don’t absorb water (styrofoam, for example) that ingredient may provide more air circulation and components such as pumice may absorb water and give it off more slowly, slowing the drying process. My favorite brand happens to have the additives. It’s called Better-Gro® and I get it from my Lowes Home Improvement garden department.

My watering is the same regardless of brand, my fertilizing (feeding) is the same, and I can’t detect any preference on the part of my plants. I have seen differences from bag to bag or more likely from supplier to supplier in terms of how broken down or decomposed the bark is. Some of it seems to be more decomposed initially than others. The former has more of a dirt-like feel to it and the latter feels like crisp, hard pieces or chunks of bark. The Better-Gro I buy is the latter. Better Gro also makes a formula that is pure bark. I like and purchase that one as well.

I do happen to have one bag of bark chips that are deliberately much more finely ground, making for a more dense potting mix and more root contact (and probably less air circulation).  I use this for the few orchids I have where the roots need to be kept on the more moist side. For the most part, however, my standard bark is coarse chunks of bark. Period.

I also use an all-bark (coarse) mix by Miracle-Gro® and like many Miracle-Gro® products it includes some food that is intended to last something on the order of six months. It works well and my plants do fine. I don’t vary my feeding schedule with my favorite fertilizer even though there is supposed to be food in this bark.   Regardless, I still use my current fertilizer with all plants, including those potted in this mixture. The fertilizer I use is low in N, VERY high in P, and low in K. It provides a lot of support for blooming and that’s why I use it. More on that in the chapter on “Feeding.” Since I use it very diluted and for a very specific purpose, I don’t worry about the fact that there is some additional food in the Miracle-Gro bark. My only concern about this product is that it appears to be more decomposed than the Better Gro product. The Miracle Gro product almost appears like bark mixed in dirt, whereas the Better Gro bark appears to be clean, fresh chunks of bark. The primary difference is probably going to be the effect on watering. The more dense mix is likely to not dry out as fast and should probably be watered less often. That’s why I usually use only the Better Gro mix so that my orchids are all drying at about the same time.

Pots

Regular clay plant pot

I use only clay pots, with the size appropriate to the size of the orchid in question. Different genus’ have different requirements. For example if you are repotting a Cattleya, where the rhizome grows along the surface of the bark, you need to have a couple inches free space from the growing tip to the side of the pot to allow for additional growth. For an Oncidium, on the other hand, where the the new bulbs appear randomly, you would position the plant more centrally. This is a conventional clay plant pot properly sized for this Dendrobium. Also notice the tag from the nursery identifying the plant, and I have an extra tag in the pot with the date of the last repotting. I found it impossible to keep track of when each plant was repotted and adding tags was the only solution.  The extra tag in this photo is probably another hand-written tag identifying the plant. If I have several and lose one, I generally keep the tag in anticipation of separating the plant again at some point in the future.

Clay orchid pot

There are clay pots and there are clay pots. There are clay pots that are called “orchid” pots. They have openings in the clay near the bottom edge of the pot. The intention is to allow better drainage. However, if a regular clay pot with a bottom drainage hole has a large random chunk of bark over the bottom hole, drainage shouldn’t be an issue. And if a pot isn’t draining correctly (that is, quickly), I simply poke a finger in a large central drainage hole or a stick in a smaller drainage hole. The bark simply needs a little “encouragement” to not close off the drainage hole and everything is fine. If these are available and they are the same price as regular clay, I sometimes buy them.  But if they are more expensive or not available, I’ll generally buy regular clay pots.

Repotting the Phalaenopsis

As you can see from this first picture, the person who gave me this Phal either didn’t know to care for it or didn’t have the time to. The leaves look sufficiently healthy but the roots on top of the soil don’t look so great. Some look dead and others look very dried out. There are old dead, dried flower stalks that have been cut back but left longer than necessary. The medium it is planted in looks literally like garden soil. I think it was probably a more finely ground bark originally or coarse bark that has simply decomposed over the years. But it has certainly broken down to the point where it has a soil-like consistency. The problem with this is that there is little air circulation provided to the roots, the condition of which we’ll check in a moment when we un-pot it. What is obvious from the combination of the stressed roots, the heavily decomposed bark, and the multiple old, dead flower spikes is that this Phalaeonopsis probably has not been repotted in years, perhaps not since it was purchased.

That question is answered in this next picture. I found this plastic liner in the flower pot which lacks drainage holes. This is a very common way for bulk orchids to be potted and sold. The plastic doesn’t allow good air circulation and because the outer pot lacks drainage holes, the holes in the bottom of the plastic pot don’t do any good anyway. So drainage is nonexistent and if this plant is overwatered, especially combined with the decomposed bark that is too dense to allow good air circulation, these roots will eventually drown or suffocate. The good news is, there’s plenty of healthy plant to work with here and we can easily salvage it. In fact, it’s still healthy enough that it even has a new flower spike about a foot long already. It is mid February in Kentucky as I write this. So this plant should flower in March or April and with luck, stay in flower until possibly as late as June or even later. You may be able to see in this picture that the roots circling the bottom of the plastic liner are a vibrant, healthy green. If you can’t, take my word for it. They are. This Phal has also obviously lost a few of its lowest leaves while being kept by the original owner which, in itself, isn’t an issue. That’s how Phal’s grow. They add a new leaf or two to the top each year and occasionally lose a lower one, slowly elongating  (or more accurately in the wild, generally growing sideways in a typical Phal fashion that you will get to know if you keep them for any length of time. They all tend to do it.)  But they should be repotted about once per year (every two at most) with fresh bark and they are typically planted a little lower each time. They continue to grow from the top and throw off new roots at the bottom leaf-joints, so as they lose the lowest leaves they will either naturally grow more and more “stalky”, or sideways as they would in the wild. In captivity, pot them a little lower to maintain the same proportions and size over time (once it has reached full size). Also, my preference is to repot the plant as upright as possible each time, as you can see in these pictures, even though the natural growing habit of Phals is to grow substantially to one side, as in the original picture above.

In this next picture you’ll see I have washed off the old potting medium and have started to trim the roots. Some of them are dead and obviously so. Some just appear to be stressed and look poorly. Since the plant will be repotted in fresh coarse bark with lots of air spaces, there should be a flush of new root growth this spring. So this plant should do fine. For now,  I want to leave enough to keep the plant healthy, but the trimming can be equally healthy as well, removing some of the longest tips of even healthy roots to reduce the root mass overall. I have also taken the opportunity to trim away almost all of the dead flower spikes. Like some of the other orchids, new flowers can appear on old stems of Phals, but only stems that are alive. That’s easy to tell with Phals. (Not so much with some of the others, as you will see in other parts of the website.) Non-viable Phal flower spikes will simply be dead. They are brown and dried out, as the ones in this picture.  But when a Phal is done blooming, the owner should cut the spike just above the very first node closest to the plant and see if the remainder of the spike survives. If the spike stays alive (green), there’s a good change it will throw off another spike from the first one, right at that first joint, rather than starting a new one from the base of a leave. In can do either. And occasionally, both!

Here is the final root trim job. I’ve left enough to be healthy, made some room in the pot, and taken off everything that was either non-viable or questionable. At this point I can put a little orchid bark in the bottom of the pot (a clay pot with drainage holes), put the orchid in root-first resting on the bark in the bottom and then carefully fill all the spaces around the roots. You want it well filled, but not so tightly packed that you defeat the purpose of having a very airy medium that will allow lots of air circulation. With coarse bark, it’s nearly impossible to compact to the point of dangerously reducing airs spaces. After I have filled in all of the available space by hand around the roots, I take a wood skewer (a shish-kabob skewer) and gently work the bark in to make sure there are no overly large air cavities either. You want air circulation. But you don’t want such large cavities that parts of the root can dry out too much between waterings.

Here is the surface of the Phal as I finish putting in the new bark.  Notice the orchid wire laying across the pot. This is the next to last step of repotting most orchids. The curved part closest to the camera is forced over the edge of the pot and the long portion holds the bark and roots in place. It simply adds stability to a traditional potting arrangement (orchids in coarse bark that is not very stable by itself). Notice in this case the pot is smaller in diameter than the length of the wire. Not to worry. The wire can simply be bent to conform better to the shape of the pot. In the next photo, the wire has been bent and installed so that the entire plant in the pot in the bark is very stable. It can now be watered thoroughly and put on a saucer in a light spot (not direct sun) and away from my other plants for at least a few weeks – because it is a new addition to  my collection. While I’ve kept enough Phals for enough years to know through casual observation there’s a 99.9% chance there is nothing wrong with this particular plant that a little TLC won’t cure, it’s a good practice to isolate new plants for a while. And I hate to violate good practices!

Here’s the final plant with the bent wire. Notice I have also added a plant label. This is the last step with ALL my plants when repotted. Label them. You simply can’t remember everything about every plant. (I also save the photos of the plant and tag and flowers. There is a file on each plant on my computer so I really do have a complete history of every plant. But not everyone wants or needs this level of detail.) Notice the name on the tag – “Patti.” I also know where it came from . Notice the date. I know when it was last potted. With approaching 100 orchids, it’s impossible to know when they were potted and when they need re-potting. The dates tell me. I glance at the dates when I water the plants twice weekly. I know when one is going to need repotting.

Growth habit affects repotting decisions and tactics. With the Phal above, they are almost always a single plant. The normal growth pattern for Phals is to add leaves to the top and lose them occasionally at the bottom, all the while throwing off new main roots just above the soil surface near the base of the plant. So it’s a perfect candidate to simply trim the roots and plant it a little deeper each time it’s repotted.

(Phals are generally propagated by a practice known as meristem cloning or propagating, where a growth tip is cut off and put into a special medium in a flask that is agitated to keep the cells separated until there are a large number of viable cells, at which time the aggregation stops and the cells are allowed to start developing into individual plants. You can even purchase flasks that you can then separate and pot up dozens of identical plants if you wish. The old days – of keeping an old Phal healthy until it finally threw off a pup was one of the reasons orchids used to be so expensive and are now available virtually everywhere.)

Repotting a Phragmipedium

Phragmipediums are one of my all-time favorite orchids. This picture is of the China Dragon (Phrag. Grande 4N x besseae flavum), the first Phrag. I ever purchased years ago. It was a dry stump when I purchased it and it was clearly viable. I potted it up years ago and it’s grown and thrown off new plants ever since. Phrags. are more difficult than many orchids to keep, however. They are more temperature sensitive, tend to not do well being watered with chlorinated water, and need their roots to be kept moist virtually all the time.

As it turns out, though I didn’t know it at the time, the China Dragon is either one of the easier Phrags. for novices (I still consider my self a novice!) to keep, or it simply happens to like my environment (temperature range and the water I keep in jugs for a week to allow the chlorine to evaporate). I only found this out when I purchased another Phrag. in mid-2016 that was one of my more expensive purchases, and I’ve managed to just about kill it. I have kept my China Dragon in fine bark chips for years, and kept water in the saucers so that the roots stayed damp. I potted my new Phrag up the same way and the leaves took on a very unhealthy pallor, the new growth tip in the center has died, and I took it out of the pot to take a better look at the roots and they are all practically dead.

After frantic emails back and forth with the orchid grower I purchased it from, it seems there’s “wet” and there’s “wet” when it comes to Phrag. roots. They grow theirs in sphagnum moss only. And that’s what this orchid was planted in when I purchased it. I probably should have never changed it over to the fine bark.

Becoming more concerned, I also took my China Dragons out of the pots (they’re grown and spread and I’ve given a few away) and checked their roots. While some looked pretty good, there weren’t as many as I would have expected. There were several new “pups” growing off the main roots, but the root balls on the primary plants were sparse at best. So I’m experimenting with repotting ALL of my Phrags. in sphagnum moss. Here is one of my original China Dragon’s still potted in fine bark.  I actually have two pots of them about this size from previous divisions. So the first thing I did was to take all of the plants out of the pots and clean off and wash the roots.

The next thing to do was to separate off the pups. There were no damaged roots to remove. The main plants simply didn’t have a lot of roots. Fortunately, the two pups had good roots. As you can see from the two arrows, there were logical places to cut them free from the main plant. They separated nicely and appear to be great little starter plants. The good news is, even though my fine bark may have not been the best media to use for Phrags., it wasn’t the worst for the China Dragon. At least I didn’t kill them, as I did with my new purchase.  But, even though the bark was less than a year old since the last repotting, it still was broken down more than I would have liked to see. The result was a really wet mass around the roots that really didn’t allow much if any air circulation at all.

Here is the sphagnum moss in a pan of water. It needs to be soaked in water before it can be used. It is sold in small dry bails wrapped in plastic. Separate it gently and let it sit in water for a while to moisten it before you use it for potting up orchids.

I then proceeded to put a clump of it in the bottom of the pots over the drain holes, then held the plants with the root balls in the pot while I carefully placed wet moss all around the roots.

TIP: Don’t pack the moss too tightly. You’ll defeat the entire purpose of allowing moisture PLUS air circulation. Use traditional orchid wires on the tops of the moss to hold the plants in place. You want the pot full of moss, but not tightly packed.

Here is one of the pups before it is potted separately. Notice the healthy new roots. So my fine bark wasn’t the worst thing in the world – but perhaps not the best. I’m hoping for better root growth in moss since it will allow better air circulation. I will have to do some experimenting, however, with how frequently to water them now, and whether or not I’m going to want to keep water in the saucers. I keep several old plastic milk jugs with water in them just for my Phrags. because of their sensitivity to chlorine. The jugs sit for a week or more before being used to allow the chlorine to evaporate from the water.

 

I am very pleased with the final result. The two pots were eventually split into five. I could have made six, separating one of the larger plants into several sections. But I opted to see if I could get them to develop healthier root balls before I split the larger plants further. The two pups were potted up separately and I think they will make dandy orchids to trade or give away. Four of the five pots are shown here.

Repotting a Cattleya

Other plants, however, grow by sending out new growth essentially along the surface of the soil with the roots protruding downward from the main stem and thick, heavy leaves protruding from the top. The Cattleya’s are a good example of this growth habit. For these orchids, I use essentially the same bark, but when the orchid growth reaches the side of the pot and starts wanting to grow over the edge, it’s time to repot.

With this sort of growth pattern the main stem is simply cut. The primary decision is where to cut. What you will be doing is keeping the front, newer portion of the plant and positioning it in the pot with the cut edge closest to the side of the pot, thereby giving the growing tip some open pot into which it can grow and throw off new growth in the form of new leaves and typically, new blooms. The rule of thumb is that you want at least three leaves in a remaining section. So if your pot is big enough that you have six stems with leaves on top, you would cut it into three and three. If you have more, I’d provide the extra leaf or two to the newer growth that you want to keep.

The BIG question is what to do with the portion cut off. In my experience, if I have a three-leafed section of the oldest part of the plant and I repot it separately, it tends to through off new growth of its own and become a second plant. Unlike Phals, where you typically can’t produce extra plants through the repotting process, you almost always do with other forms of growth habit. And Cattleya’s are a good example of this. I keep the old growth watered and treated just as I would any newly repotted orchid and if it seems to stay viable, I give it away to one of my “orchid buddies”, people who never seem to be able to say “no” to a free orchid gift of my extras. (I used to keep them until I grew my personal collection to the point where there was simply no more room. At which time I realized I’d have to part with my “doubles.”

Repotting an Oncidium

Oncidium needing repotting

Oncidiums and similar orchids have an entirely different growth habit. They have large plump bulbs called pseudobulbs that grow from a rhizome that grows along or just under the surface of the growing medium (coarse bark chips), with leaves protruding upwards from the bulbs. This sort of plant grows by producing new pseudobulbs at the growing tip of the rhizome. These plants get crowded in the pot as more bulbs and leaves are generated to the point where the new bulbs are at the edges of the pot and are being literally forced over the edges, as in this picture. Oncidiums tend to grow in the direction of the rhizome, similar to Cattleyas. But you may have several plants in a given pot without realizing it so that bulbs could be appearing in spots that appear random but are really at the growing tips of multiple rhizomes. (There are actually three different categories of Oncidiums based upon growth habit, but mine are all of the category that sends pseudobulbs off the central rhizome and leaves protruding from the pseudobulbs. That’s what we are repotting here. The second category have very small pseudobulbs with single leaves, and the third category has no pseudobulbs and has leaves growing in a fan-shape.)

Oncidium unpotted, roots not washed

If you have enough material to separate into multiple plants, this is accomplished when it is repotted. I take the entire orchid out of the pot, remove as much bark as possible, and then separate the plant into new bunches of logical size. “Logical” is relative. What’s logical of you may not be for me. For example, if I want a huge specimen, I might not actually separate the plant at all, but remove old or dead bulbs and pot the entire plant into a larger pot each time. Or I may want to take a very healthy thick clump and separate it into two or three smaller plants and pot them up either in the same sized pots or smaller, depending on the size of the bunches. Regardless, if the plants are viable, they will throw off their own new pseudobulbs and the process continues until they need repotting again.

Oncidium roots washed. Notice dead pseudobulb.

Here is the Oncidium pictured above, but with the roots washed. Notice the vast majority of the roots are very healthy and some of the oldest pseudobulbs are dead from old age. These will need to be trimmed away. Good roots are valuable and you want to retain as much as possible in most cases. (My Phals tend to develop such dense root balls they actually need trimming, even where all the roots are healthy.)

Separated naturally into two sections

In this next photo I found that this particular plant was actually two. After carefully separating roots, I found two completely separate rhizomes with 7 or 8 healthy bulbs on each group.

Carefully look over the plants and determine where you want to make cuts. You should have at least 3 healthy pseudobulbs and plenty of roots in any given group to make sure it will be viable.  There is a very good chance that one or two pseudobulbs with good root systems would live, but there’s no point in tempting fate. I’ve never repotted an orchid with three or more healthy pseudobulbs and not had a viable, healthy new orchid. What is as important as healthy pseudobulbs is healthy roots. What you won’t succeed at is transplanting healthy pieces of orchids with poor roots. So given the choice, separate less if you need to to keep an entire section well rooted. You can always divide it more later, but only if it survives. So it’s better to be more conservative rather than less when it comes to how much to divide.

Oncidium cut in two pieces

Each of these sections could be divided into two healthy plants. But that means they need too be cut apart because all the pseudobulbs are growing from the same rhizome. Here I am using a good pair of garden shears to cut this plant into two separate groups of three and four healthy pseudobulbs each. In fact, of the two primary plants pictured above that came out of the pot, each plant can be safely cut into two, rendering a total of four much smaller plants.

Oncidium being repotted in coarse bark

Here I am potting up the first plant. I put a couple of larger pieces of bark across the drain hole in the bottom to keep the smaller pieces of bark from falling through. I put a small amount of bark over that to provide a solid base. Then I hold the roots loosely in the pot with one hand while I distribute bark around the plant with the other. As you can see in the picture I use a skewer (shish kabob) to “tease” the bark into the root ball. you want to make sure there are no air pockets. Air pockets don’t provide enough contact with the bark and allow the roots to dry out too quickly.

Oncidium freshly repotted in coarse bark with wire and tag

Here is the final repotted first plant. The the pseudobulbs and leaves are not growing directly vertical. They are growing to the side in the direction the original material was growing. I’ll place this plant with the direction of the growth pointing away from the source of light, in this case, the window. That way phototropism will work in my favor. Phototropism is the tendency for most plants to grow towards the strongest source of light. So the plant will tend to send its new growth in a more vertical direction. Technically, I shouldn’t have potted this plant in the center of the pot. The growing tip of the rhizome will tend to put all the new growth on one side of the pot. Like Cattleya’s, I should have potted the older cut end very close to one side of the pot and leave the most growing space on the side where the new growth is anticipated. But the plant looks nicer – more balanced – if it’s potted in the center. Notice the wire clip holding the plant securely in the bark, and the white plastic tag that identifies the plant and the date it was repotted.

Three more Oncidiums to pot or give away

And here’s the bonus. There are three more plants from this one separation. Three fortunate people will get new orchids. If you’re in a hurry, and/or don’t happen to have extra bark and pots around, friends who want orchids will be just as happy to get them with a wet paper towel around the roots and put in a plastic bag to contain the moisture until they can get them potted up. I keep a detailed list of local “orchid buddies” who love to adopt my extra cuttings. These will be gone in 24 hours!