soil mix for square foot boxes

ekreider wrote:Do not substitute composted manure for compost making up a third of your mix. The nutrient level (and smell) will be way too high. Treat composted manure as fertilizer.

Everything I have seen about mushroom compost is that it is a pretty good source of organic matter but has little nutrient value because the mushrooms pretty much use up the nutrients. Five to ten percent composted manure with the rest mushroom compost could be a good way to approximate good compost.