Re the genus Ariocarpus:

I have created this in response to the watering thread, I was only going to write a little bit on sand but got carried away.

First I will say growing this genus successfully and most importantly vigorously is an art form and takes many years of experience to master. I don’t claim to have excellent knowledge and expertise, the following is simply my opinion and what I have read and experienced.

The problem with growing Ariocarpus vigorously is two fold; first they have a huge tap root which is a hindrance as much as it’s a blessing. The tap root is used to store water more so than nutrients, which is an adaptation by the plant to survive long periods without water and this consequently makes the plant VERY susceptible to rot if over watered.

Due to the size of the root you would assume the plant would grow much faster than it actually does but as stated above Ariocarpus tend to store water rather than nutrients in the root and this dramatically slows growth. As a result the plant will be dormant (or very very slow) until the tap root is “full” of water and this is where the real problems start. There is a very fine line between having enough water to fill the tap root and having too much water where the root will begin to rot.

The aim is to give the plant a large volume of water that will fill the tap root and then dry or evaporate quickly. There are several ways to achieve this but the most important factor is the potting medium. It must be almost entirely made up of inorganic material that will allow for good drainage. The following are examples of what can be used in a typical soil mix:


Scoria – Volcanic Rock.

Pumice – Another Volcanic Rock, much lighter then scoria.

Vermiculite – A mineral rock that is heated to form a porous medium. Apparently as vermiculite breaks down it provides nutrients to the plant but I cannot confirm this.

Perlite – A Siliceous volcanic rock with properties similar to glass.

Charcoal

Various other rocks

River Sand – I no longer use sand in my Ariocarpus or Astrophytum soil mixes. Sand tends to retain moisture and fills up the pores in the volcanic rocks leading to a more dense mix. Additionally most bought sand has lots of silt still with it and once it gets wet the silt turns in to a slurry and mixes with the sand, once it dries it sets very hard and does not allow for good drainage or root formation.


There is no right or wrong soil mixes, but a good soil mix will make growing Ariocarpus much more forgiving. Have fun with and I hope this helps someone.

Hey HN good advice there.

Vermiculite is one that always gets me as its holds water. Have used it with vine grafting and the sticks once grafted get packed into it after its been wet and they are kept in this for over two weeks and it does not dry out at all. I have read so many times about people using it and it always seems strange to me. Does it not get wet when the plant is watered?

Would love to hear your thoughts on this.

Yes it gets wet and I know what you mean about it beind hard to dry. The reason it works is due to the soil around it. The surrounding soil will dry quickly and due to it being made up of porous material it will absorb much of the moisture from the vermiculite.

I don't personally use it in any of my mixes.

Hahaha i see this, just as i repotted about 6 plants
I dont use any flash mix, 50/50 $2 bag of compost and sifted sand. I remove the dust and leave the quartz pieces(sand) but i cant remove all the silty sand.

Ive already potted up a few of my Astro's in my normal mix, but in a few months or so i plan on potting up my Asterias/Myrio/Capricorne's, comeing from an experienced grower of Astrophytum, should i keep the mix as is, so i can just water on my usual routine with everything else, or should i make the mix as porus and free flowing as possible?

MichaelCactus,

Mate it all depends on your climate. It is very feasible to grow Astrophytum sp in a standard potting mix and during the growing season you should have no dramas so long as the soil completely dries out. The problem is when the season changes and you need to water less frequently.

As I stated above a free draining mineral mix will be less prone to rot and in essence will be much for forgiving if you over water a little or the weather becomes humd for a prolonged period.
HN

Hmm im not too sure at the moment. I think i will stick with the normal mix so far, i really dont water alot when winter comes around, if so a little trickle.

Great write up! One question. Where are these components available from and are they easy to get? I live in relative isolation and don't have a vehicle per se so was just wondering about this. I have never come across pumice for sale yet.

Me neither Trig........

Courious whats the writing mean???

Trig and betty,

You can buy Scoria and Pumice at most of the larger or dedicated Landscaping places. I got my last lot from Flowerpower landscaping. The problem is finding it in small sizes 5mm is usually the smallest meaning you will have to break some of it up fun.


The rest of the ingredients you can get at most Nursery's or even Bunnings will have most.

HN I can get scoria easy enough but in big chunks but as of next week it will be so much easier for me to get what I want............have already found a nursery with little scoria close by my new home

I think many people like Ariocarpus but we know it is growing very slowly with own root.
My seedlings sown seeds on 30/09/06 were also very slow growing.
I got a information and test a differnt way from last spring.
Feed a lot of water in spring and summer
Keeping under very weak sunlight
Repotting in spring and autumn twice per year (autum has not come yet and not has never done yet)

I think it seems this way works well.
The attached photo is an Ariocarpus fissuratus.
Pottingmix is Volcanic Basalt
Top dressing is Zeorite

Awesome info man,I just acquired a new Aricarpus,and I want to insure that it stays nice and healthy

root pruning, when a little larger, is a great way of increasing capillary roots and speeds up growth a bit (speed is a relative term with ariocarpus lol!). there are risks, but if you do it all clean and dry, its the preferred seed grown method around these parts.

Been meaning to try that technique Kada. Is there a detailed section on root pruning taproot cacti on your website?

If so link me up mate. Be good to have link for the root pruning tech in this thread anyway.

Cheers.

Hi !!

Here is a good horticultural supplier. The have just about everything you may need for potting mixes, sands, pumice, pots, etc. And they deliver interstate as well.

http://www.smoult.com.au/home/