I recently repotted about 6 marigolds and various herbs into my gritty mixture. Its been one week, 5 of the marigolds look completely dead, and about 1 of the 5 herb plants looks like it will make it.

I also repotted a peace lily a few months back and it completely died within 2 weeks (brown to black leaves).

I take the plants out of the soil, shake away the dirt, wash it of all dirt in a bucket, untangled the ball, then repotted in the gritty mix.

Where am i going wrong?? Is there a thread that has very specific details about the proper way to repot plants into gritty?