I see this type of post often about MG or Scotts TR ferts soil, or other similar chem type fert soils being too hot for young seedlings. (too high on N) It depends on the strain. In any case, if you just lighten it a little bit by adding maybe 25-30% perlite it won't be too hot. It will grow and spread roots much better with the addition of the perlite anyway. Especially when they are young / small. If that's all that is readily available to you, get it and just add the perlite and it will do fine. Just realize that the nutes in it will get used up after a while and you will have to add / use ferts eventually. Also, adding some type Epsom or similar suppliment is sometimes needed.

bob