Is there something wrong with my Sulcorebutia rauschii?

[WayneByerly]

In October of 2016 I bought a Sulcorebutia rauschii from some unremembered person on Etsy. When it arrived on the 17th of that month, it was bare root and it looked like it had been so for months. It was SO dry that it was desicated, withered and shrunken. I was really concerned that it would not make it. Here's what it looked like. It is the only picture included that has a dime in it for scale (for my European readers, a dime is 17mm wide):

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I immediately arranged living quarters for it, burying it about halfway between the "top" of it's roots and the very top of the cactus itself, and gave it a serious soaking. By the 20th of November (just over a month later) it had improved significantly although it still had some "shrunken" appearance.

Its "soil" is 1 qt worm casting, 1 gallon bark fines, 1 gal coir, and 1 gal volcanic rock. The mixture is light and airy so that the roots grow easily without stress, it drains extremely well and quickly but yet retains some degree of moisture. I believe the worm casting provide an excellent source of organic material satisfying its nutritional requirements. I allow the soil to dry out almost completely, and then give it a good soak.

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By the time an additional week had gone by, it looked to be what "I" would call normal, and I put it in the greenhouse where it has been until today. My greenhouse is thermostatically controlled. The heat comes on at 40 degrees fahrenheit and goes back off at 45 degrees, letting the cactus experience a "winter" without getting excessively cold.

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So I have questions about its appearance. I bought the Sulcorebutia rauschii as a replacement for one that I killed due to over-watering. So I know what a S. rauschii is supposed to look like. Round and globular. This one now looks a though it is suffering from etiolation despite it being in the brightest environment that I can arrange. It looks healthy, but it looks more like a columnar cactus. Here's a side view of the main cactus with 3 of its 4 offsets visible. I neglected the stage prop dime for scale. So that you know, the main body is now 1 3/4 inches tall & 3/4 inch wide, and the offsets are something in the area of 7/8 inch tall & 1/2 inch wide.

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This top view shows the main body, the four offsets that it came with and one additional offset that has developed in the last 10 months (at about the 5:00 position on the main body).

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And a closeup of the top of the main body. You can see that it still has new growth on the top as was evidenced by the picture "1.3".

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But it just looks too tall, despite its otherwise healthy appearance, and I write hoping that someone with some experience growing this cactus can let me know if there is "something wrong" with it, and if so, what I might do about it.

Should I have buried it deeper? If I did so now, would its newest "5th offset" suffer? Was the severely dehydrated condition it arrived in responsible for its present condition? It looks healthy, but it is just too tall. Is there "something wrong" with it?

[hegar]

I am impressed by your obvious growing skills manifested in the recovery of your cactus! For most of us - even yours truly - the image sequence would be reversed, i.e. when we planted the cactus it looked fine and a few weeks or months later it was on its deathbed.
Another thing that astonished me is the composition of your growing medium. I do see, that the worm castings does balance out the bark fines and do agree, that coir is better than peat- or sphagnum moss when growing plants belonging to the cactus plant family. Perhaps the Sulcorebutia rauschii will tolerate or even thrive in a "soil mix", which that high of organic matter content. Most desert cacti would not fare well, unless at least 50% of the volume of the medium they are planted in is inorganic in nature. At least that is the standard opinion held by the majority of cactus growers.
In the nursery business - at least for seedling cacti - there also seems to be more organic matter being used and the small cacti are doing well.
Those small plants also do get watered more often than a larger cactus would.
Now to the appearance of your cacti. To me they do look like they are doing well and you are supplying a good growing environment and doing an excellent job at keeping these plants in a thriving condition.
I do not know, if other growers do this on occasion and what the outcome is, but I would not bury the plants deeper, in order to obtain a plant that looks more like it should. With some genera/species that may be OK, with others it might not. The tops of your plants are not etiolated and the bases will not grow enough in diameter to give you the wanted "rounded shape". Perhaps your cacti were grown too close together and/or not transplanted soon enough, when they were raised initially. What you could do though, is to fill the pot to the rim with pebbles. That would make your plants look more like you would prefer them to look, by covering up the thinner bases.

Harald

[WayneByerly]

... Perhaps your cacti were grown too close together ...

It is one plant with 4 offsets... Wish i had a pic of it before it got planted.

And I am really quite embarrassed by your effusive praise over my growing skills. I'm really quite an amateur at this although I have and still do extensive reading on the subject. I've only been doing this since 2009. At this point I have somewhere around 90 different species of succulents... cacti and others like Euphorbias, Haworthias & Echeverias, etc. Its a derned addiction... I wish there a 12 step program.

I must say I'm really quite inclined to follow your suggestion about increasing the amount of inorganic material. I think for two reasons I will stick with the small diameter volcanic rock. One is is that plants in Hawaii (which is a volcanic island) just grow like cancer cells. I have quite often read something about the addition of volcanic material to soil to increase the mineral content of the soil. Presuming that plants like that kind of thing. The second is that the stuff is extremely light. Which would tend to make it easy for roots to grow. They don't have to work so hard pushing through a heavy material.

All in all I'm very grateful for your reply and your comments. I know I have learned something from this and hope that others may also. Which is a partial reason for my making the post to begin with.

[hegar]

One short note: In order to keep your cacti growing in a compact manner, give them enough light and use a fertilizer, if needed, that does have the second letter "P" (Phosphorus) larger than the first "N" (Nitrogen). Also, make sure, that the "K" (Potassium) number is not too small. Nitrogen is needed for vegetative growth, phosphorus for flowering and fruiting, and potassium for photosynthesis and translocation of assimilated photosynthates.
I am using Miracle Growth Bloom Booster fertilizer with the N-P-K formula 15-30-15 and apply it at half the recommended dosage. That is fully sufficient for cacti.

Harald

[WayneByerly]

I was just thinking about making an addendum to my last post as I think that many cacti aficionados might benefit from the following thought. So I am glad you have written again, giving me the motivational push I needed to actually sit, compose my thoughts, and write.

One thing that I have discovered in all of my reading, research and growing of cacti is this: while cacti are well adapted to exist in a xeric environment, in soils that are astoundingly devoid of organic components, and will quite readily survive such conditions, many will not actually thrive without more water & better nutritional conditions than they would nominally get in their native environments. Quite often, forcing xeric conditions on cacti will result in their responding with less than stellar results.

Not only that, but I have found that each individual species has its own individual--and sometimes profoundly different--requirements for water and soil, and some will not only tolerate, but thrive with much higher doses of water than others. Not to say that all Cactus should be given higher doses of water than are nominally recommended, but that some, in order to thrive, do require higher doses of water.

I have had cacti that were planted in communal conditions respond exceptionally differently to similar conditions. One Cactus would look like it was suffering from far too little water while its companion would die of root rot brought about by too much water. It is just astounding to me how differently two species of cactus will react to their environment.

And considering how differently they react to the same levels of water, I do not for the first moment believe that this is not also true of their organic component requirements. I have bowls for other succulents which are doing quite well in their communal environment, but I have ceased to house cacti together for that very reason.

Thank you very kindly for your recommendation and tip on fertilization. I'm very much appreciate it and will immediately seek your recommendation for the brand name.

[Grimm]

Whatever is wrong with the old growth, the new growth looks fine. I would wait a while longer and see what the cactus does now that it is happy - It should eventually cover the older growth with offsets.

[WayneByerly]

The S. rauschi when it arrived had 4 offsets. It now has a 5th that can be seen in picture 2.2 ... not very big yet, but its doing well enough to start to produce more.