i just found miracle grow organic garden soil at big lots for $8 2 cubic ft., good ass deal imo, got composted manure, and obviously has a high clay content, so its a good idea to mix it up with some fluffy amendments.
if i were u, dig your plant back out, and add some perlite and coco coir and whatever other good stuff u can get your hands on, worm castings, humus, green sand, gypsum, lime, guano, and bio-tone starter plus (got a lot of beneficial bacteria and mycorrhizae in it)