I have read "All New Square Foot Gardening" by Mel Bartholomew.  Patrick (my son) helped me build the boxes a few weeks ago.  Used the wood from the greenhouse. Mel's mix - vermiculite, peat moss and compost.  Purchased 5 different composts - sheep, cow, shrimp, mushroom and seaweed.   I got slats free rom Hodgins in Shawville.  It should be 6 inches but I think I only have 4 in.   Hope it works.
Cost:  $25 compost, $17, $7 sale at Canadian tire - tomatoe plants- yellow and cherry. $10 nails and hammer. Vermiculite - still owe Marcottes for this - didn't have a price at the time.  $15 peat and compost at Golden Lake, $5  seeds and $6 tomatoes. $85 all together.  Need to buy more peat moss for the other bed.  Using old seeds.  Cheaper than getting it disked in the fall and plowed in the spring and a lot less work.
Today I planted pepper and Broccoli - 2 per sq foot (was supposed to be one)
peas and yellow beans - 9 seeds per sq ft
Melon, 1 per 2sq ft, Tomatoe was to be 1 per 9sq ft but I mostly have cherry so I put 1 per sq foot
Summer savory 4 seed /sq ft
ThenI cut the grass all round and then whipper snipped - It was a jungle out there.  Will post pic tomorrow of progess.