Can you use charcoal ashes from a BBQ grill to fertilize plants? I thought about that myself, but I was afraid of introducing anything toxic in there. I know they add chemicals to the briquets.
Mitt beat me to it!
Definitely look into what your local soil already has, how acidic/alkaline it is etc before adding anything to a garden bed. Also keep in mind which plants are going to be *taking* certain nutrients from the soil, and which ones will *add* them.
We're looking into doing a few raised beds this year so we can grow potatoes and carrots too.. they don't like the density of the earth here where I'm at so we have to do raised beds with different soil. It's gonna be fun!