I grow a lot of adeniums with mostly inorganics. I use a mix of turface, perlite, or Napa oil dry. I usually add some granite and/or SeaChem Flourite but the only difference is that it never gets cold here. It rains often but the soil is dry in a day and a half. I use more organics with my seedlings - half potting mix with all the mentioned "rocks" above. I would say its nearly impossible to get root rot if you just stick with inorganic soil.

I'm just learning about adenium. I have mine in 1:1:1 gritty mix (turface, granite, pine bark). I'm starting to switch to 100% turface with some plants, which I'm initially liking more. In sum... I've had no root problems with any plants in gritty mix - it's so well draining, it's hard to imagine root issues.

@Jon I thought so too. Try watering an Adenium when the temperature is around 40F and you might get a different opinion.

@westes Calfornia SF Bay

I don't think they like it that cold, regardless of the soil? Do you prefer organic for colder temperatures? From what I've read from others, they either don't let their adenium get that cold, or they really don't water it once they force dormancy?

@Jon the rule is to not water when they are dormant. That said, given that my climate is very borderline for leaving an Adenium out in cold Winter air, I want to find a soil that minimizes the chances for root rot. Gritty mix does have some organic components, and that might contribute to root rot in borderline conditions.

I still routinely get root rot on new succulents that get planted in gritty mix. It is some kind of transplant shock because I bare root the plants. The plants are typically coming from a nursery mix that is peat moss and pumice. If I get twin plants, the one that I transplant to a new peat mix seems to always immediately thrive. The ones that go into gritty mix almost always go through a very rough acclimation period and many of those get root rot.

Interesting. I haven't had that experience. Occasionally, if I repot one of my jades, it will drop a few of its old leaves that should probably be removed anyway.

@Jon I find Jade plants to be indestructible.

@Dain Do you calibrate that 50F to daytime or nighttime temperatures?

I'm the same as Dain. No water under 50 when outside. I bring mine inside once it's below 45ish. Then inside I water once a month very lightly. I go by the lowest temp expected at night.