Go look at their piles and smell them. A horsetail patch growing out of the back of one (I have seen this, perhaps more than once) would be a definite red flag for me. I don't like a lot of floury fine soil particles or evenly-sized, non-decayed organic particles (bark etc.) in stuff that is supposed to be a good soil, ready to be planted into either.

Likewise sour smells.

The more like genuine, naturally formed soil the better. In fact, if you can get real soil do that. I once made berms here from pit run sand out of a local quarry and got great results from a variety of plants put right into it, without modification.

you could save a ton of money if you have or borrow a truck and get free soil from craigslist.

just make sure you get the soil from an area you know HAS good soil, inspect it, etc. be picky. pass up clay.

Free soil is often fill dirt - low fertility, poor texture and with all sorts of bizarre debris included. And no control over weeds. If filling a new raised or terraced bed area, it would not be my first choice :-)

You want to focus on bulk soils that have a lower compost component. Compost is not really fully 'finished' and will experience considerable shrinkage as it continues to decompose - as much as 30% or more. If a high compost soil mix is used, the soil level next season could be significantly lower and create problems for existing plantings. You could add to it but that becomes a bother. If you feel you need compost, use it straight as a mulch or topdressing.

I've used the Sky mix (the 3-way, not the premium) many times on various jobs as well as Pacific Topsoil's 3-way mix. IMO, the additions included in the premium blend are unnecessary, create some of the issues outlined above and just boost the cost. I've found both to be excellent, fertile and well-draining products that produced no inherent weed issues.

i am assuming when you talked about boulders arriving, you were going up a few feet. i'll stick with my fill dirt in that case. compost on top. just like a regular old garden bed. but taking care to use good fill dirt.

if you are just going up a foot, then yea, compost. just pile it higher than the rocks, and it should settle down at a normal level.

thanks for the input everyone.
I am planning to mulch on top when I'm finished planting.

I'm just still worried about the weed seed in anything with "topsoil" in it. I haven't had good luck in the past with that.
I'll have to check if the sand added to compost is pit run--(does that mean it is coarse and uneven sized sand?)
One place says that pit run is definitely not for planting.

Making everything higher anticipating shrinkage is a good idea.

Does anyone know what 1/4 - 10 gravel is? I've seen it recommended for use in soil for rock gardens.

No matter what, I'm sure the moles here will have a heyday making new tunnels!

Pit run is the soil they are getting the sand and gravel out of before they separate these out. Natural vegetation, usually a woodland or forest is growing on this before they clear it and dig the pit. So, it apparently can grow plants. And even where the fact that it is from down low in the pit might indicate it is significantly different from the stuff on top, where the forest grew since in this area most pits may be dug out of undifferentiated glacial till - there may be comparative uniformity from top to bottom.

And they certainly are still able to get enough sand and gravel out of it to make it profitable. The benefit to the gardener of ordering pit run is the implication it will have a high sand content - where that is desired. The stuff I got certainly did, plus in that instance it was not full of rocks. Think it may have been sold to me as pit run sand.

1/4 10 is a sort of sharp pea gravel. its crushed and screened rock, with no fines.

levels out very easily and holds the level (unlike pea gravel) when mixed with soil. even not mixed with anything, it holds a level pretty well (no walking on sand kinda feel like pea gravel) i like it for paths and i use it to level my lawn (top soil and seed the top). i've seen it as a top dressing for potted plants.