Just a slightly different take on this. Bagged manure available around here from the box stores has a VERY low content of actual manure -- in most cases only about 10%. Yes it can provide some tilth to the soil but very little in terms of fertility, and in my experience does not really add much to the soil. Mushroom compost, on the other hand, is made up virtually completely of composted manures and has a much higher organic/manure content than the bagged manures available here. Unfortunately, where I live mushroom compost is virtually impossible to find, none of the stores sell it and it is no longer available in bulk any where in SE Michigan that I know of. I did manage to get one load of mushroom compost about 5 years ago and used it as a soil amendment in areas where lime loving plants grow, like hellebores and clematis. Those plants grew like crazy! I know it is somewhat basic but that can be corrected depending on what you are growing and your natural soil pH. I know at Ashwood nursery in England, probably the premier hellebore nursery in the world, they made beds largely of mushroom compost, and their hellebores in the garden were to die for. So....take from that what you want, but wish I could get some more mushroom compost. Having said all that, if you have made beds the way you describe and are adding that much organic matter every year, your soil is probably in great condition and you probably only need to amend or fertilize around hungry plants (clematis, roses, hellebores....) BTW, dehydrated manures are sometimes available bagged, and while much more expensive than the box-store bagged "manures", add much more fertility and tilth to the soil IMO.

What a great question -- you made me look it up. I read somewhere (not sure if true) that mushroom compost is usually basic (and for that reason, not to be used on my blueberries). That would be one difference. Mushroom compost is a by-product of mushroom farming. I think it does not have as much nitrogen as manure compost (since the mushrooms used most of it already) and there's a warning that the salts in pure mushroom compost may burn seedlings. Depending on the supplier, it may also have pesticide residues?! Ok, now I'm wondering WHY I put 2 bags of it on the veggie bed instead of using cheaper chicken manure compost. Phooey! :(

The current price is $5 per truck load. They have a website with their address posted on it so your friend can mapquest directions.

In a discussion of mushroom compost a while back in an azalea group, someone pointed out that this compost is alkaline and not good for acid-loving plants. So please be careful about what you put in your raised beds, if you're going to plant shrubs -- Leafgro is neutral, but manure can be too high in nitrogen unless well aged and mixed with other stuff (better for veggies). Might want to consider starting your own composting area now that you have the room and material for it....