I'm doing some gardening for a friend. She has raised beds (brick
walls about 30" high). She's complaining about the quality of the soil
in the beds, wants me to remove all plants, dig in "soil improver", and
replace selected plants.

The soil is black and fine, but seems very "heavy" -- perhaps "dense" is
a better word. I'm wondering if it's the type of stuff excavated from
river basins and sold as topsoil: it's a bit like the silt you'll find
beside a river. Naturally my first thought was simply to get bags
of compost and dig it in, but I'm aware that these days there are
several kinds of "soil improver" on the market, so I'd prefer to get
some advice first: I'll need a dozen or more bags to improve the top 6"
of the total area.


By the way, I've haven't done a Ph test, and cannot at the moment
because the job is in another town, about 150 miles away.

TIA for any comments,
John