Repotting your Disas

Here is a fairly typical example of a plant that has bloomed and in fact might still be in bloom since we can't see the top of the plant.  The circled new growth has just broken the surface of the pot and is in a rapid growth state.  BTW, notice the brown appearance of the leaf to the left of the circle.  This is an example of the Colletotrichum gloeosporioides fungus that caused quite a problem for me in the spring of 2001.  It is treated with Dithane and a decrease in the humidity of the growing area.

The material on the top of the pot is a coarse washed sand.  One of the many things I have tried to help keep the surface of the pot clean and dry, and without moss, slime or liverworts.

Here is a plant that is overdue for repotting.  The original plant is nothing but a brown rotting stick at the end of the arrow.  If you pulled on it, it would probably come right out of the pot.

The picture on the right would be what you would see if you depotted the above plant.  Notice how all of this year's growth is all brown and rotting.  Notice the quantity of dead material also. The new growth has light tan roots that are noticeably whiter at the tips.  Notice also that there is no branching.  The roots are very fragile and once broken, don't regenerate or branch like some epiphytes.

The pots that I am currently using are called "Tagloc" pots and are noticeably deeper than they are wide.  This is helpful for plants that have long tubers. The clay colored pots are 12.7, 8.3, and 10.7 cm wide going from the right to the left.  The larger black pot on the left is only used for especially large plants and as a compot for newly deflasked seedlings. The smaller black pot is a McKonkey's SR350 and is still used as an alternative to the clay colored one in front of it.  I am switching to the clay colored pots to decrease the root temperature.

OK, let's start looking at specific examples.  Consider the pot on the right.  It has a brown stem from a flowering, plus 3 larger new growths and a number of smaller growths.

When dumped out and washed with a spray of water, you can easily separate the roots of you use a loose mix like my preferred mix of "Supersphag" and perlite.  If you have a number of plants, this mix greatly simplifies the repotting process. I can't say too much about this new mix.  It has all the advantages of long fibered Sphagnum moss and none of the time consuming problems.

After repotting, the new growth provided enough plants for 4 new pots of material.

The pot on the left provides the next example.  Notice that the older growth is practically all brown.  Notice that the pot also has a layer of moss growing on the top of the pot.  This moss growth is not encouraged.  With heavy overhead watering, it is almost impossible to curtail.

Upon knocking the root ball loose from the pot, we notice that the potting mix is different.  This is representative of the mix that I used before I switched to Supersphag / perlite as my mix of choice.  This is still a good mix to use but it has a couple of problems.  One is that it is much more time intensive to prepare. 

You can see that the roots are nicely developed on both the new growth and the old growth.  Again, consider if you would want all the rotting plant material found in the old rotting roots present in the pot if you didn't repot.

It's easy to separate the plants when you use a sprayer like this.  It's a simple mechanism with a "Fogg-it", 4 gal./min. nozzle on the end of a thumb-trigger valve.  A brass quick connector and a brass shutoff valve complete the set up.  This can and is used for washing agar from deflasked seedlings as well as  to clean the roots when repotting.

If you are doing a number of plants of the same cross, it is sometimes convenient to hold the plants in a tub of water while you are waiting to pot.  This is more important when the temperature is higher, as you can't allow the roots to dry at any time during the repotting process or anytime, for that matter.  I find it convenient to use a 6 quart container sold for storage at most department stores. This is about the size of a shoebox and I fill it with about a gallon of tap water to which I add a capful of Safer's Vitamin b starter solution which contains the rooting hormone NAA, one capful of a product called VF-11 which is a non urea containing fertilizer, and 10 DROPS of Physan 20 which is a general fungicide / bactericide.  Checking the TDS gives a measurement of 130 to 180 ppm.

After potting, I sometimes wash the plant free of potting material.  The pro's are the removal of anything to catch moisture on the leaves but it also packs down the potting material and if you water from below, you would like the potting mix to be as loose as possible, especially on the surface so that it dries out a bit and helps discourage the growth of moss on the surface.

Here is another example of a mature plant ready for repotting.  Notice the two new growths twisted together and the brown old growth.

Knocking out the root ball and putting it on my wash screen ready to wash.

A simple squirt of the sprayer easily washes most of the potting mix away.

Here we see two new pots of material and the old plant material resting on the old potting mix.  This plant was repotted about 8 months prior to this photo so you can see that the sphagnum is still relatively fresh.

Here we see a pot ready for repotting.  The old growth is completely brown and there are 4 new growths poking through the surface.  I have a tendency to leave the pot alone until the old growth is completely brown.  I feel that as long as the original growth has chlorophyll, it is contributing to the growth of the new material.

The root ball literally crumbles apart once it is removed from the pot.

I try and lightly grasp the new growth while I wash away material from around the roots with the sprayer. This method is very effective and doesn't damage the fragile root system if you use an open mix like SuperSphag / perlite.

After a squirt from the sprayer, you can see more of the root structure.  The arrow indicates a new stolon and the tuber is clearly visible to the left and parallel to the arrow.

I made this picture large so that you can see more of the detail.  The "A" arrows indicate stolon growth, "B" indicates where the old growth was attached to the tuber and "C" indicates the start of a new shoot which will develop it's own tuber.  The tuber is visible also at the end of the "B" arrow. Notice that the new roots are cream white on the ends and also notice that there is no branching in the root structure.

After potting, the old pot has yielded four new pots of material.  The two largest pots will surely bloom this next Summer.

That's pretty much enough for repotting from pots that have older decaying material in them.  The question arises what to do about seedlings, though.  A properly grown plant should not bloom before it has a tuber or else it will die after flowering and the plant will be lost.  This means that you should repot twice before you have a mature, tuber forming plant.  Often you need to repot when both the old growth and the new growth are still green.  It's a bit harder to tell when to repot in this situation but not really that difficult.  The following material should help you to repot those seedlings.

It's often difficult to tell from the top of the pot as to which plants are old and which are new growths with tubers.  Once you get the plants out of the pots, it's easier to tell what's going on.  On the left, the old and new growth are connected by a "dropper" which is indicated by the arrow.

Sometimes you have this situation where the new growth hasn't even broken the surface yet. The arrow indicates the dropper between old and new growth and notice that the new growth is white because it hadn't yet broken above the surface level of the pot yet.

In this photo, the "A" arrow points to the dropper while the "B" arrows indicate new stolons.  These new stolons are extremely fragile and are often broken during the repotting process.  Often there will, be a new plantlet developing on the end of these stolons.  If there is a plant on the end, and it has at least one root, you can pot it up and it will usually survive.

Here is a typical seedling in a pot.  The new growth has broken the surface of the pot and is growing rapidly but the old growth is dying.

This is a photo of the cleaned root system from the same pot.  The arrow points to the dropper.

Here we have broken the dropper just by snapping with the fingers.  The old growth is discarded.  Even if you pot it up, the old growth will usually just quickly die down so it's easiest to just discard it when repotting.

This shows another seedling which has been washed off and then broken mid dropper where the two lines are.  The old growth on the right is discarded when repotting.

The situation here is a bit different and is handled differently.  The new growth hasn't broken the surface yet and lacks any chlorophyll.  If you broke the dropper at "B", the new growth may or may not make it.  Notice that the old plant was from a stolon that is still visible at "A".  The stolon has rotted away from the plant and the end is circled while the old roots are indicated with arrows.  Notice that they are brown at the tips and dying.

Since the new growth doesn't have any useful chlorophyll yet, I leave the old plant's leaves attached to the new plant by the dropper. I have removed all the old roots and the old stolon so that when the new growth breaks the surface and the old growth turns brown, I can just twist the old growth off leaving a minimal amount of rotting material to bother the new plant. After I remove the old growth in this manner, it is not necessary to repot.  That's why I removed most of the old material to start with.

Here's what it looks like after repotting.

When repotting, I try to slightly overpot.  This is contrary to some others opinions but I feel that the plant will grow to fill the larger space.  I also try to pot fairly deeply.  In this instance, I will plant the new growth almost right up to the green on the stem.

Another example of overpotting.  The circle is where the dropper was attached to the top of the tuber.

I hold the plant in place while I fill the bottom of the pot and then once the plant is in place, fill loosely to the top.

This is what it looks like after I finish.  Notice the material is still very loose.  DO NOT pack down the mix.  Try to keep it as light and airy as possible.  If you top water, the mix will gradually compress but there is no need to help it along.  If you bottom water, the loose material on the surface will dry out much quicker than the material in the pot and help to keep down the growth of undesirable weeds, moss, and liverwort.

Newly repotted material in a flow table enjoying the cool autumn temperature but growing well in their new pots.

But it' obvious that I still have lots to repot.

I have tried to present a fairly complete picture here but I have done enough potting so that perhaps there is an aspect of repotting that I am overlooking or taking for granted. If there is any part of this process that you still don't understand, please let me know via email and I will try and enlighten you.