Question about soil

Hi guys, today I have a question about the soil you use for your plants. For my mammillaria, I use a soil made of generic soil found in woods and fields and pumice, with variations for species with different needs (more grit, limestone....) but sometimes I have troubles with the drainage. Can I ask what do you use for make the soil for mammillaria and for what species in particular you use special variations?

That's a good question and I hope that people will reply with their experiences. What works for me is a mix of a loam-based soil, horticultural grit and either perlite or pumice or if I can't get either of those I will use moler clay (sold here as cat litter). So basically two thirds of the mix is non-organic and is mineral based. I never use any extra limestone.

Thanks, I think that I will reduce organic percent in my soil and learn about your experience. Any other who use different compositions?

I grow all my cacti in pumice (bims), nothing else, i.e. no organic matter. The pumice is from the German Eifel region and the brand is Vulkatec.

Thanks Wolter for your reply. Waht do you think about the wild growing method?

What do you mean by 'wild growing method'?

Cultivate simulating the conditions and terrains of the locality where the plant grows

It's too difficult to simulate the natural conditions and to use soil from habitat. It is also unnecessary. I have been using pumice for a long number of years already and I am very satisfied with it. Of course, there is no fertilizer in it and so you will have to add that from time to time, preferably with a relatively low N content, e.g. Ferty4 (N-P-K 8-16-24) or Peters' Professional Blossom Booster (NPK 10-30-20).

Similarly, after many years of cultivation in a substrate with the addition of organic parts, now I use a mineral substrate. A mixture of lava, zeolite, expanded clay, coarse sand, pumice. For lime-loving species, I use gypsum as a lime additive. Experiences with the addition of limestone rocks were bad. Gypsum is a sulphate and European rocks are carbonates and have a different pH value

Thanks Wolter and Marek, so if you grow plants only in mineral it means that you all had bad experiences with organic in the compost. What kind of problems did you register?

Once i used peat moss in the mix. That caused root loss. When its wet there is not much problem but when it dries it causes root rot/loss in the capillary roots.It doesnt happen immediately, it takes some time. Later plants get shrink up and you understand that there is a problem. I lost a lot of seedlings because of the peat moss in the mix.
Lava stone crush dust also is not good in the mix, this also causes root loss. I always sift lava crush stones and eliminate the dusty parts. I dont use it.

When my substrate had an organic additive, I had problems with fungal diseases, but also often there were dark/brown discolorations of the thorns on white mammillarias (plumosa, gasseriana, lasiacantha, sanchez-mejorade, humboldtii, herrerae, etc.) starting from the substrate and moving towards the upper part of the plant. I could not remove the discoloration in the way I know. I added forest soil, partially decomposed needles and leaves as an organic additive. Like Wolter, I do not add dust or clay to the substrate. I most often use fractions of 4-8 mm. If I make a mixture of various mineral aggregates, I put them in a container outside so that they combine well. This takes 0.5 to 1 year. The mixture did not have a good effect on the plants right after making it.

Thanks guys, that's precious for me