I am in the process of planning my first SFG. I was hoping to get the boxes made and filled before winter and then plant in the spring.

My house sits on 10 acres of land (zone 5A), with about 4-6" of topsoil sitting on top of clay. I have a nice clear section near the house picked out for my garden. I was planning on constructing bottomless boxes and lining them with cardboard bottoms to kill off weeds. This will (hopefully) gain me a few inches of depth once the cardboard decomposes. There are four people in my family (two adults and two kids under three). I was planning on constructing 7 4'x4' boxes and one 4'x4' "highrise" box.

Questions:

1) The six inch depth of the boxes worries me. Should I make 12" boxes instead? If I make 12" boxes, would it be appropriate to fill the bottom 6" with plain compost (not 5 different types thereof) instead of Mel's Mix?

2) Am I making too many boxes for a first year?

3) Is a layer of cardboard sufficient to kill off weeds? I was considering putting down weed paper, but if I do that I lose any "extra" depth I could steal from the existing soil - correct?

4) From reading on this forum, it seems that people find MM insufficient for the first year without adding further fertilizer. Should I add in fertilizer when mixing my MM, or should I be fertilizing at regular intervals throughout the first year?

5) I was planning on using the "highrise" box for carrots and maybe potatoes. However, I would also like to put in an entire box of asparagus (which I love). The SFG book doesn't seem to recommend a highrise box for asparagus, but other information I've read indicates asparagus needs a deep bed. Given that I am only going to get another 6" (max) out of the soil before the roots hit clay should I be making a tall box for my asparagus plants?

Sorry about the long post :) Thanks for any help you can provide.

Sarah