Mineralized topsoil

Works awesome in a lowtech without any added ferts--more like a Natural Planted Tank but not "raw" dirt.

You can use these in all levels of low, medium and high tech.
I'm about to start a medium-high tech 75G with this method. It's messy to make but once you get it going it's really easy and straight forward. Much cheaper than aqua-soil...

Just make sure you have a cap...of sand or gravel.

Read the sticky, find out who made it and check their journals. Very highly recommended.