potting medium suggestions for pachycaul trees

I ordered an Bursera fagaroides and Operculacarya decaryi from arid lands. Both were in 4 inch pots before they bare rooted them.

I have coarse perlite, coarse gravel(it's smooth),plain potting soil(no additives), oil dry, and a little bit of composted cow manure.

With these ingredients what would be a good potting medium for them?

They will be grown under lights for the winter until it stays warm next spring.

Also should I stick them in four or six inch pots?

Andre may be a big help on the one from Madagascar. I don't know how you could go wrong with coarse gravel. I think I would avoid the potting soil- fined roots may sit in water too long. Perhaps sifted pine bark instead, in a small ratio? In our local club, collectors have come back with desert junipers, and they swear by pumice.

Well I ended up potting them in an inorganic mix of coarse gravel, coarse perlite, and oil dry.
Anyone want me to post pics.

Always like pics, if it's not a bother.

Andre, still hoping you'll weigh in on this. Busy Spring?

Here are the pics.
Bursera fagaroides
Operculacarya decaryi

Arnt you in the beginning of winter?

I can help if I dont know you live. Arkansas sounds somewhere in Canada.

If so , you did the complete wrong thing. I wouldnt even dare to fiddle with the roots of such a young Operculacarya let alone do it before winter.

Busera fagaroides will live though, its the rezin tree family like Frankincense... But it also needs to rest and dry. But keep it in full sun.

What is Oil dry? It sounds toxic... hihih hihi hi

Love and Light

yes andre, you are correct in that arkansas is near canada
really just a bit south of canada...
well... actually considerably south of canada...

aw heck now that i think of it, maybe even closer to mexico

and oil dry s/b just diatamaceous earth/fired clay

Andre is right, winter is not the time to disturb the roots of either of these species. IF your winter growing area is warm, Above 70 F (20 C) even at night, both these species will keep growing with good light. So to get new roots to form, keep them warm, give them sun, and water after the media dries out for a day or two. Bursera are relatively easy, forgiving. The Operculacarya is less forgiving, but might pull through. Mine would grow any time there was heat, sun and occasional water. Your plant is so small, that it will not tolerate extended dry spells. Once the Operculacarya has a trunk over 1 inch in diameter, you could just leave it bone dry and leafless all winter. Start watering when you set it outside in spring.

Cool (less than 65 F, or 18 C) and wet will likely cause rot in the Operculacarya.

I use a mix of pumice, perlite, and crushed granite, no organics. Your mix will work.