I really like Black Gold organic potting soil.
To make soil adequate for seeds, I think you can just run it through a colander to remove the big clumps- what you want is a uniform consistency that holds moisture well enough that the seeds don't dry out between waterings.
To make soil adequate for seeds, I think you can just run it through a colander to remove the big clumps- what you want is a uniform consistency that holds moisture well enough that the seeds don't dry out between waterings.