I have only done a couple of soil grows but I've used Fox Farms - Lite Warrior for the seedlings since it's quite mild, transplanting into Ocean Forest after a couple or three weeks when they can handle it. I use 25% Perlite with both. I also put a 1/2" layer of Perlite at the bottom for good drainage.

First time I tried to grow I used a recipe with Ocean Forest, worm castings, top soil, blah, blah, and it burned the crap outta my seedlings so I always start them with the Lite Warrior now.

Two or three plants should be good in that space - may get crowded but manageable.

Happy growing! :thumbsup: