Turbinicarpus

[BobbyZ]

I just purchased four small Turbinicarpus: lophoides, saueri, homipilus and jauernigii all around an inch in diameter. I have not had luck with this genera. What is the best soil mix, I know they need lime. Can I put all four in the same pot and fo they have similar requirements. How deep does t6he tap root grow?? Feedback will be appreciated. Thanks Bobby Z

[adetheproducer]

I just purchased four small Turbinicarpus: lophoides, saueri, homipilus and jauernigii all around an inch in diameter. I have not had luck with this genera. What is the best soil mix, I know they need lime. Can I put all four in the same pot and fo they have similar requirements. How deep does t6he tap root grow?? Feedback will be appreciated. Thanks Bobby Z

I grow lophophoroides on pure mineral substrate. Crushed limestone, sandstone(welsh penant), red granite, brick and then mix in some fine gravel. No actual dirt at all. They grow well and my mature one flowers very regularly. I water profusely during the summer without concern as the soil drains very quickly. Its about 2 weeks into winter rest now and looks like a new flower bud is showing so still growing even in the cool temperatures.
I dont have any of the other species you mentioned but do also grow macrochele, pseudopectinatus and alonsoi with virtually identical mix but with clay, corse sand and loam added to fill the gaps also very good results but much more drying time required between waterings.

[Steve Johnson]

I know they need lime.

No they don't, and I'm not sure about how the idea that Turbs "need" lime in a mix for container cultivation ever got started. Perhaps it's more of a preference among some growers, but Turbs do perfectly fine without it. Soils that are composted with organic materials can be problematic for the genus, so better to go with a very lean mix and little or no organic stuff in the soil component. And believe it or not, your Turbs should do great if you grow them in straight pumice. If you don't have a source, try this:

http://www.ebay.com/itm/3-5-GAL-PUMICE- ... 3384a94694" onclick="window.open(this.href);return false;

Don't try putting all 4 in the same pot since the species you're dealing with are likely to have different watering needs. If you're looking at about 1" diameter per plant, then each should be in its own 2" pot. Depth I'm not sure about, so you'll have to see what the taproots look like when you get them. My guess is that 2 x 2 will be sufficient without jamming down on the bottom of the taproot, although you'll need to use your own judgment on this. Re. watering -- Turbs shouldn't get any water at all in winter. Most sources recommend not watering October-March, but as L.A. is about to end a nice hot October, I gave my Turbs a deep drench Saturday night. However, I think that'll be it for their watering until early spring. In the growing season, watch out for how much water they're taking up. When your Turbs look plump, they're fine -- when they start looking a bit thirsty, it'll be time to water them again.

While I haven't tried lophoides, saueri, or homipilus before, my "street creds" on Turbinicarpus include jauernigii, polaskii, pseudomacrochele, pseudopectinatus, schmiedickeanus klinkerianus, and valdezianus. Just to refresh our memories here, I grow the vast majority of my cacti in pumice and decomposed granite with the DG "play sand" fines sifted out to yield a fairly coarse aggregate. No "exotic" materials (I'll leave the limestone to other growers), and those Turbs of mine are growing very well. By the way -- while this not 100% foolproof, it's almost impossible to lose cacti that are supposedly rot-prone when they're being grown in pure pumice. (I have DG in my mix only to make the pots heavier, so IMO it's not necessary otherwise.)

[iann]

T. lophophoroides is a gypsum dweller. Like most such species, it may appear to be doing well but can collapse at any stage. The whole group does well with classic cactus treatment: don't overpot, water generously, then make sure they dry out completely. Remember rule #1: if in doubt, don't. Or at least wait another week The taproots can be huge, but they won't grow much root beyond that so don't think you will help them by giving them a big pot. The taproot will adapt to the pot to some extent, but will also break out of the pot as hint that it needs more room.

I assume you've trying growing these in "cactus soil". That won't work. They don't like rich organic soils. At best, they'll appear to do well for a while (too well!) and then die. They will be far happier in a leaner soil and looking half-dessicated most of the time. Some of them do grow in dense soils in habitat, but not overly fertile soils - limestone, gypsum, or silty pans. For the most part they also like it warm. Not sure how they do with hot humid nights, but they do like hot baking days.

[BobbyZ]

Thanks for your commednts I used a mix of 40% pumice 40% perlite and 20% commercial catus soil with a sprinbkle of lime and bonemeal. It is probably too rich in organic. The vweather here is still 27 to 30 C day and around 18 to 24 at night

[JustSayNotoCactus]

Nooooo! No lime! If you can sprinkle it, that means it is powdered lime, which is way too alkaline to put in any potted plant soil, unless you have an incredible acid problem. Chances are your local water is already full of dissolved lime, which is universally bad for plants in the first place, so why add more? What these plants will appreciate the most is a sprinkle of powdered gypsum if anything, gypsum is PH neutral, and provides exactly the same Calcium. In fact, you should read up on acidification of tap water to even further limit their exposure to lime, the stuff is so bad. Don't believe me? Well just look at almost any plant collection, no matter what kind, that is watered with high PH tap water. You will see a noticeable yellowish tint to all the plants, as compared to someone who has mastered acidification or at least has suitably acid soil to neutralize the lime.

[Robb]

In my opinion, organic soils have a bad reputation. I use about 40% organics in my mix (the rest is pumice) and my cacti do absolutely fine. I use it for all my turbinicarpus and other "Difficult" species. Obviously, if you are using heavy organics then your plants will suffer, but if you use organics like coconut coir and composted bark there is no problem. I don't like pure mineral mixes because plants in nature will grow with at least some organics. This is just my opinion and might not suit your growing conditions or climate.

[DaveW]

Don't use horticultural lime for cacti, always use limestone or gypsum if you must, but as others say it is not strictly necessary since people grow cacti from limestone or gypsum habitats quite happily without it. In fact some claim they add limestone as a growth retardant in order to keep them more in character and stop them growing too lushly in soils with a greater humus content.

A quote from the Soil Hexalogue:-

"The fact that some plants have adapted very well to alkaline pH does not mean that they don’t accept – for short to medium periods of time – to grow in much richer soils with a rather acid pH, and they might even apparently enjoy this! The real problem is that these plants will soon show aberrant growths. The alkaline pH induced by limestone is a growth inhibitor for these plants; by lacking this inhibitor plants will grow to their potential, and not to their natural size. This aberrant growth – some plants look like being literally pumped up – contributes not only to the loss of their specific natural aspect, but especially makes them weaker when confronted with biotic and abiotic factors the plants are now unable to overcome. They become literally unrecognisable – lose their compact forms, the specific colours of the epidermis, their exceptional spination becomes weaker, etc."

http://www.cactiguide.com/pdf_docs/hexalog-engl.pdf" onclick="window.open(this.href);return false;

Of course the statement that all cacti only grow in mineral soils in habitat is a myth. It is obvious from habitat pictures showing shrubs, grasses and mosses surrounding them that when these die their humus is added to the soil and has been for hundreds of years. Even plants inhabiting rock crevices may be growing in some humus that has blown into them over decades. What is certain is that using habitat soils in pots is unwise since soil in a pot behaves quite differently to that in open ground, therefore potting soils need to be far freer draining for cacti.

These cacti certainly get some humus in their habitat soils:-

http://yougrowgirl.com/learning-from-na ... rdy-cacti/" onclick="window.open(this.href);return false;

http://davesgarden.com/guides/pf/showimage/211496/" onclick="window.open(this.href);return false;

It's really a case of if you want tall, quick, bloated ("show winning") growth which more acid cultivation brings, or more compact natural habitat growth for these small cacti from more alkaline regions?

http://ralph.cs.cf.ac.uk/Cacti/Cactus%2 ... linity.pdf" onclick="window.open(this.href);return false;

Two different opinions and methods of growing plants from limestone habitats, and two different results!

Remember though not all cacti prefer alkaline soil, most S. American cacti prefer it slightly on the acid side of neutral.

I find Turbinicarpus some of the easiest cacti to raise from seed, flowering within a couple of years or so of sowing.

[adetheproducer]

Well said DaveW, I have to admit I am on the natural compact side of the fence so this is why my advise disregarded organic soils. I am aiming for the hardened growth look. Also the turbinicarpus lophophoroides is supposedly a difficult species and can be tricky with watering so my rocks only soil mix give more room for mistakes with watering and the quicker drying time allows for the ever changing climate here in Wales. I also use a deep pot due to the long and thick tap root I think a 2x2 inch pot might be a bit small to allow the big fat roots to develop. My t.lophophoroides is about the same size as you BobbyZ described but the roots are much bigger so I use a clay tom pot (don't start, there is a thread for this argument.lol) Its about 10cm diameter and about 15cm deep with the root filling most of the pot.

[iann]

T. lophophoroides does appear to be the most sensitive of the main Turbinicarpus species which is a shame because they are very nice. Most gypsum cacti are touchy (or worse!), so not really a surprise. All in all this is not a difficult group, but they don't tolerate your typical noob mistakes very well.

[BobbyZ]

Yes I repotted all my four Turbinicarpus. I used around 70% fine pumice (broke down and opened a new bag) 15% perlite and 15% Florida sand from the B horizon from planting a Meyrer lemon, I added a measley dose of horticultural lime and bonemeal. The T. homipilus was around 6.5 cmand the T saueri 5 cm in diameter and they are in 8 cm pots. The T. lophophoroides is 4 cm dia and is in a 2.5 inch deep pot, while the small T. jauernigii is 1.5 cm and i put it in a small 2 inch pot. Lets see how it goes Thanks for all the input. My wife thinks I am fanatical to repot but I want to see the buds on the saueri open. Bobby Z

[DaveW]

You may find an article on growing on rocks in the latest issue of the free downloadable Xerophilia of interest Ade:-

http://xerophilia.ro/" onclick="window.open(this.href);return false;

[adetheproducer]

You may find an article on growing on rocks in the latest issue of the free downloadable Xerophilia of interest Ade:-

http://xerophilia.ro/" onclick="window.open(this.href);return false;

Yeah I did read that when it came out and is a very regular reference. Thats it pretty much got me on to pure mineral mixes. Luckily a lot of the rocks and stone are readily available here in wales with various granites found in garden centres and local sources of gypsum dolomite, gypsum alabaster, limestone, sandstones mudstone etc its quite easy making custom plant mixes. My favourite plants are the mexican species so easy to make calcareous soil mixes, I deffinately recommend using gypsum and limestone with them. There are plenty of valid arguments against including limestone but having used primarily limestone and dolomite in my mexican mixes I am getting good strong growth with natural looking compact plants which is my exact aim.
But yes a very good read, something I also would tell any cactus enthusiasts to explore. I came to the conclusion that a lot of cacti are like mosses more than normal plants before reading that and it sort of confirmed my belief. Also as a result of using the mineral mixes I am now starting to think more research needs to be done to explore their nitrogen fixing capabilites as I have seen too much growth with no added sorce of nitrogen. I only use rain water which is pretty much in abundance here, no fertilizers and have grown seeds with finer versions of my soil mixes so no humus at all. They do grow slower above ground than I see in other growers pictures but mine have very large root systems with some of this years lophophora, ariocarpus and turbinicarpus already making nice fat tap roots.

[DaveW]

Roy Mottram (Whitestone Nurseries UK) years ago showed me some plants in a bed of what was virtually cat litter (= "grog", which is baked clay granules from pottery industry) plus coarse sand he used to sell as "Whitestone One Eleven" cactus potting soil, which he maintained had never been given any fertiliser and only water for many years. They were all still growing healthily and he wondered if either the plants or bacteria around them could be fixing nitrogen, but others seem to dispute they can, but then many would have disputed they could "digest" rock at one time?

[adetheproducer]

I would think its more than likely they have symbiotic bateria and/or fungi that do the job just as they do for mineral extraction. Im pretty sure these associations occur with all plants on land. But then they do lock in air, lots of gaseous nitrogen, as part of the CAM cycle there could even be arguments to a secondary purpose for holding in the air with enzyme activity fixing the nitrogen.