Planted Tank Enthusiast
Join Date: May 2019
Location: Palm Springs, CA
The reason people suggest using a specific potting soil & other substrates is because you have some idea of what you're getting in terms of nutrients leaching out, etc. Since you were smart & baked your yard dirt first, it shouldn't have any pests, and if pesticides etc were never used it shouldn't hurt anything. But it's hard to say how much nutrients it'll have for your plants. If if you're the patient type who doesn't mind experimenting, wait & see how it works for you. I used a non-brand organic potting soil I had on hand, and it caused an algae bloom, but was able to work through it. If it turns out your soil isn't giving your plants what you need, you can always stick in root tabs or Osmocote pellets later if needed. Most soils get depleted after awhile anyway, so you'd end up doing this sooner or later--unless you decide to tear it all down & replace it.
Yes, melting is part of the process. Just make sure you keep on top of removing the melted & dead stuff, or that could cause an algae bloom or green water. I added some cheap ghost shrimp to help clean up anything I don't see or can't get too if I'm away for a few days--seems to have helped. And they're fun to watch cruising around. Ditto for snails, if you don't mind having those.
Dosing fertilizers in the water is a whole other ball of wax--plenty of experts on here to help walk you through that if you decide to go that route.
Welcome to the world of low tech, and enjoy the ride!