I've been using a 50:50 base mix of perlite/ turface for many years. You can easily modify this mix for different needs. Most mesembs benefit from the addition of a clayey component. For me, I just dig beyond the topsoil in my yard for some good dirt. I also substitute perlite for some lava rock and small pebbles. It's a heavier, longer lasting mix which works when repotting infrequently for mesembs. This same mix is my preference for small cactus species like Aztekium, Blossfeldia, tricky mamms like luethyi, etc. "bigger" plants like some Crassula, aloes, aeonium etc. you could add more perlite to lighten big pots. It also makes it safer to leave outdoors all spring/summer/fall with rain. My palms, plumeria and cycads live in this mix too. Floating perlite is not an issue. But it does easily displace with high water pressure like from a hose. Some form of fertilizer is a must. I'm also a fan of submerging small pots with small plants into bigger, deeper containers to help stabilize root temperatures. Practically any healthy plant I've ever had to repot always has roots circling the bottom. I really don't understand the concept of shallow or regular pots. I think the deeper the better. I haven't really noticed any exception. For some species it's mandatory. Haworthias, many cactus plants with tuberous roots. Even Lithops which tolerate a shallow home will grow much better in very deep pots. Pleiospilos too. For anyone unsure or unconvinced, try an experiment. Take a pot with any plant you want, and bury it into much deeper pot for a growing season. Pull it out later and see what you find. Bury an Aloe, pachypodium or most any strong Echeveria or similar in the garden and watch it take off. We would all be great at bonsai, plenty good experience with root constriction and limiting growth lol!

@Nil13 made reference to the Whitcomb 311 mix, which is an earlier historical attempt to create a more coarse potting soil for container plants. I think it is extremely helpful to read a document written by Carl Whitcomb that explains how he came on this formula by accident. Essentially what happened is he accidentally left nine test pots under a bench and everyone forgot they were there. They had successfully nearly killed all of their test plants by watering in a normal potting soil mix and the unwatered plants started to do very well. What I have started to realize is that any plant can do well in many different soil mixes, if you are able to carefully control the watering. This explains why so many people on this forum claim gritty mix is not as good for their succulents as their (fill in some random horrible soil with lots of small particles) mix. Inevitably those people are growing their plants indoors. They have enormous experience with their plant type and they know exactly when to water the plant. So that is the case of a very skilled gardener compensating for a very bad soil. What gritty mix does for me is let me grow succulents outside in very abusive weather conditions, without the plant dying. A plant can get a week of rain and it will still drain well. During Summer, gritty mix will tolerate a bit of overwatering, although you still really need to pay attention to not overwatering. Whether you make your 511 mix with perlite/peat, or with two parts Turface, or with lava and pumice, is probably in the big picture not going to be the deciding factor in whether your plants grow well or not. Success can be add with any of those mixes because the size of the particles allows the roots to breathe and prevents capillary action of water from bring the perched water table to the top of the pot and drowning the roots. Fine-tuning how you make 511 is a question of matching the plant type to the moisture retention of the soil and to the watering habit and climate exposure. Any 511 variant is going to do better than almost any commercial potting soil because of the larger particles used in the majority of the mix.

Hello, first post here :D Can anyone recommend a source around Portland for the appropriate bark for the gritty, 511 and similar mixes? Horizon in Milwaukie (near Bob's Red Mill) carries Turface MVP, and down the road, Concentrates (across from Lowes) is a good source for granite / grani-grit, perlite and other container planting materials. Bark is another story- everything I find is too large, any help is appreciated! :D

mcreader503: If you're interested in purchasing Repti Bark, you might want to check your local PetSmart. Online the 24 qt price is $13.46. I (and the store personnel this evening) was shocked that the shelf price still showed up as $25.99. They had no problem honoring their own online price. For me, $13.46 for bark chips/fines is still pricey, but I don't have a source for bark fines out here (that I can determine) -- Houston area. Good luck.