I, for one, would be very interested to hear SpanishFly's soil mix recipe. I am relatively new to growing cacti, but I love finding new ways that I can spoil my babies!

Spanishfly said

I have used ground up eggshells when my usual crushed marble has not been to hand - all these things are basically calcium carbonate, or lime. My standard mix for Mexican desert cacti is 2 measures loam, 1 measure wormcasts, 5 measures sand/grit and 2 measures lime.

Entheo, there are probably as many soil mixes as there are growers - but for those who have asked here is mine for Mexican desert cacti -
I use the same mix for peyote and all my limestone-loving Mexican desert cacti - I just sieve it a bit finer for sowing seeds.

2 measures loam
1 measure wormcasts
5 measures coarse sand/grit
2 measures crushed marble

Gives a well draining alkali soil with a little nutrition, which is similar to what many desert cacti grow in.

Substitute for what you can´t get - if wormcasts are a problem use bat guano (if you are rich) or rotted horse manure (if you are poor). I can buy huge bags of marble chips which I crush up coarsely - I would use dolomite lime if I could get it. Otherwise crushed sea shells or egg shells - all are calcium carbonate.
Good luck
Regards
Fly

Thanks! I am aware that everyone pretty much develops their own mixes and whatnot, but I'm always curious to hear other people's ideas and methods. I've been using a mix of 7 parts perlite, 4 parts potting soil, 2 parts coco coir, and 1 part worm castings. I use this mix for all of my cacti, most of which are Lophophora or Trichocereus species. I don't hear them complaining, so I guess it must be satisfactory!

I have a bunch of calcium carbonate that I have considered expirementing with, but I worry about adding too much and damaging my plants. The fertilizer I use for my Lophophoras also supplies a decent amount of calcium, and they seem healthy. As they say in the south, "Why fix it if it ain't broke?"

I don´t think you will give too much - in the pic there is a Epithelantha micromeris and another (?) growing in almost 100% limestone in their Mexican habitat..

So I have kind of a goofy question.... how do you crush your marble exactly? I got a bag of marble at the garden store but they are rather sizable stones for a small pot and even bashing them with a hammer did barely anything to break them.

I eventually got some smaller pieces to use but it still makes it difficult when measuring ratios and whatnot.

When i crush stone, lava rock i use a big hammer. I do this in the concrete. I dont know how spanish does it. But be sure to use goggles and gloves. Its a heave thick looking hammer.

I was hitting the stones with a mallet on concrete but then I decided to stop so I wouldn't crack the concrete. I tried it in the grass but it didn't work so well. I didn't know it would be so hard to even chip these stones! It's a violent procedure.

I tried mixing spanishfly's soil mix but I got all wrong ingredients or something it ended up being a really weird mixture that took several hours to drain and turned into cement. I realized that i was using bad ingredients. The limestone I could get around here was in balls that turned into a mud real quick, couldn't find loam anywhere so I used topsoil, and it didn't end up being a good consistency. I ended up giving up on finding limestone or marble (that wasn't in giant rock or mushy ball form) and now I just use a mix of pumice/decomposed granite chunks/sand/coir/worm castings. Drains super fast but holds water for a day or two and is vary aerated. Spanishfly's mix obviously works extremely well for him though.

Where do you get your loam and limestone spanishfly?

Loam is topsoil - I go and dig some up.

A local garden centre sells big bags of marble chippings - they break up real easy for me - marble is not a hard rock - I am surprised you were having problems. Sure it is marble??
I find lava rock, that I break up to make coarse, porous grit, to be somewhat harder to crush than marble.

I put a handful in a plastic bag and bash them with a hammer - I get a range of sizes, from coarse sand to lentil-sized pebbles, which I like.

Lime is basically calcium carbonate - alternatives are crushed sea shells or even egg shells.

Hi Spanishfly,

Beautiful plants you are growing there.

I try to grow Peyotes but i dont get them past one or two years after which they always seem to get this hard outer skin.

See here: https://www.dmt-nexus.me...amp;m=506972#post506972

Do you think this could be a soil issue ? Or do you think it might be sth else ?

Thanks !

I concur with what many folks have already told you on that link - looks like red spider mite. Get some specific insecticide.

Yea I got marble but they are the kind of stones for landscaping I think. This is why I don't like asking people in the store to help me because they never seem to know what I am talking about. I went to this huge garden center and they didn't have wormcastings, lime, or coarse sand.... or so they told me

edit: It does actually say "marble chips" on the bag but they are for landscaping. They are rather large for a small lopho pot and I was railing on them with a hammer to no avail. I might try to crush them again or I might just go to the store for something else. It was only $5 thankfully

Ok thanks, i will give that another try, as i have allready.

Should spider mite be visible ? Im pretty sure there are no tiny bugs strolling around on the cactii, ive even checked by photographing the plant from all angles and blowing up the photos to enormous size.

Spider mites are tiny - you need a lens to see them.

I have the same scaling on some of the peyote's I picket up at the local gardening center. They are flowering and producing seeds. I have checked with a lens and can't seem to find Anny bug on there as well. maybee its something else, like over watering?

So far a big mystery I have put them in another room to make sure they don't contam the other cacti

I think it has to do with my soil. I initially gave my peyotes the same soil als my san pedros, so they have way too much nutrients and way too little lime. So i have followed Spanish flies soil mix and will now wait to see if they recover.

I used crushed see shells for lime.

Sounds like your ingredients were TOO fine and dusty. Mud is basically wet dust, and mud can become a hard substance when dried - as in mud huts. I try to keep the sand, grit and limestone - which is 70% of the mix - relatively coarse, with a range of particle sizes - so roots penetrate easily and it drains well.

http://ralph.cs.cf.ac.uk...%20and%20Alkalinity.pdf

Here's an interesting read that I found about alkalinity and cacti. I figured I'd share it here since all the discussion about pH and whatnot.

Knowing is half the battle!

i'd jus like to say ur mix worked for me!

I used fox farm soil for Loam