Most plain topsoil is what was stripped from farmland prior to the building of new homes. It might have started out as good soil, but after being stockpiled, sometimes for years, it becomes compacted. This results in the loss of much of the important microbial life. Adding compost will help restore life to the soil.
The sight of all these bags must be confusing for the new gardener. I wouldn’t have a clue what to use in my garden or in planters if I was just starting out. Garden soil, three-way mix, black earth, potting soil, and what about the equally attractive bags of compost that buttress those bags of soil? There’s sheep compost, cattle compost, maybe horse or even chicken compost. Whenever I pass by I find myself humming Old MacDonald’s Farm.
Which one to choose? For small raised beds, the three-way
mix, much the same as triple mix is fine. With the one labelled simply as
garden soil I’d be inclined to add the compost of your choice. Plain garden soil is fine for a garden, but not recommended for
planters — a soil-free mix can be better for that purpose.
Black earth can be a puzzle, and I don’t know why it’s called earth and not soil. It would be easy to assume that because it’s black it must be nutrient rich soil; however, that isn’t necessarily so as good soil comes in all colours, like the red soil of Prince Edward Island, for instance. Black soil (or earth) could have come from a swampy area or it could have been darkened by adding leaves. Unlike the composts that are produced and sold, there are no requirements for the analysis of plain soils unless the producer does it voluntarily.Compost is regulated by the provincial government as well as federally through the Canadian Food Inspection Agency. Regulations are set out to ensure heavy metals and other toxic materials etc. are not present. . For more information on compost, see The Compost Council of Canada website.