garden centre "top soil"

[brianw]

Top-soil is a very "local" product, and can never realistically be a countrywide standard product. If I buy top-soil from the Bagshot area (near RHS Wisley) I expect to get mainly sand; if from Bedford area mainly an acid silty loam, incidentally the basis of the original John Innes composts. Unless you know where branded products originate your guess is as good as mine as to what you are going to get, and presumably they can alter that souce at will, as the term implies nothing more than the surface few inches of soil, depending on previous cultivation regimes.
My preferred JI type compost supplier went out of business a year or so back, so I use Arthur Bowers as the base for all my mixes now. It is close to what I remember of JI composts way, way back except for less grit and more very hard lumpy "peat" content.

[Lesley Cox]

We would buy topsoil from a supplier of compost ingredients like bark, grit, peat etc and it had always come from local areas being developed for housing. The majority of the soil must be retained for putting back on site but some is sold off and is usually good quality soil. There will be an assortment of weeds in it though. Depending on what they are, it doesn't matter (easily removed annuals) or it matters a lot, (convolvulus, oxalis, sorrel, californian thistle.) You pays your money and you takes your choice but it pays to have a good look through it and pick up quite a bit by hand, before deciding.

I always add pine bark fines, some grit and composted pea straw to mine if it is available.

[Anthony Darby]

I would use the word substrate as a general term for the stuff in which plants grow. Compost is broken down organic material which can be used as a substrate or used as part of a mix.

[Darren]

I would use the word substrate as a general term for the stuff in which plants grow. Compost is broken down organic material which can be used as a substrate or used as part of a mix.

Exactly the point the lecturers are making Anthony and the distinction is clear enough when you think about it but the word compost is often used for bagged 'substrate' of all kinds. I bet even totally inorganic substrates such as used by some cactus growers still gets called 'compost' by some!

[mark smyth]

I've set some of Westland's and Evergreen's 'soil' in the green house to dry out. I added Westland to water also. It looks identical to Evergreen's except there is more ?peat floating.

Should I write to both companies and ask what is in their bags?

Evergreen
http://www.evergreenpeat.com/display.asp?prodID=168

Westland
http://www.gardenhealth.com/products/compost-and-growing-media/soil-improvers/top-soil/

[Anthony Darby]

I would use the word substrate as a general term for the stuff in which plants grow. Compost is broken down organic material which can be used as a substrate or used as part of a mix.

Exactly the point the lecturers are making Anthony and the distinction is clear enough when you think about it but the word compost is often used for bagged 'substrate' of all kinds. I bet even totally inorganic substrates such as used by some cactus growers still gets called 'compost' by some!

Quite so Darren. Compost, to my mind, is something made from organic waste in a heap or bin. Another perfectly good word hijacked for use where there isn't a satisfactory alternative. "Can I have three bags of John Innes number 3 substrate" somehow doesn't trip off the tongue?

[ChrisB]

Not come across this term before, so I just looked on Wiki and it says:

    Substrate (building), Natural stone, masonry surface, ceramic and porcelain tiles
    Substrate (aquarium), the material used in the bottom of an aquarium
    Substrate (vivarium), the material used in the bottom of a vivarium or terrarium
    Substrate (biochemistry), a molecule that is acted upon by an enzyme
    Substrate (materials science), the material on which a process is conducted
    Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached
    Substrate (chemistry), the reactant which is consumed during a catalytic or enzymatic reaction
    Substrate (marine biology), the earthy material that exists in the bottom of a marine habitat, like dirt, rocks, sand, or gravel
    Substrate (printing), the base material that images will be printed onto
    The stratum on which another geologic stratum lies

[brianw]

I think of a "compost" heap, as a rotting down mixture of anything I throw on it. In the same way Garden Centre compost in a bag is a compost (composition) of mixed ingredients. Just we shorten the original word a bit.

I only wish big furry animals with long tails would not make their home in it. Reptiles are welcome, Ratty is not.

[Lesley Cox]

A croc would be welcome?

[Anthony Darby]

I think compost from composition is an extrapolation too far.

[bulborum]

I think I am Happy
that A company is making my own potting mixture

I just order 4-, 5-, 6 M³ Big Bags
and they make the receipt I want
I took some time
but now most of my bulbs grow well

Roland

[Anthony Darby]

I just deal in wee bags at the moment. I couldn't even justify a hand turned cement mixer.

[mark smyth]

Today I bought some John Innes 3 that was made by Westland. What a load a cr@p. It looks identical to their 'top soil' except it comes in a bigger bag. When I emptied the bag in to the wheel barrow the most noticeable thing was the amount of ?silver sand and how fine and 'fluffy' the mix is. I would have expected to see grit. A hand full felt light.

Forum members mention their favourite JI products. What does your favourite look and feel like

[Paul T]

It's funny.... I would never consider using top soil in a pot..... soil is for ground, potting mix is for a pot.  The drainage of garden soil is all wrong for a pot, holes clog etc much more often.  Potting mix is designed for the drainage etc that we are wanting in a pot.  I'm assuming from your description above, that what we call potting mix is what you are calling potting compost?

Compost to me is broken down organic matter, like from a compost heap. broken down leaf litter etc, as others have mentioned previously.  It is interesting how differently (and confusingly if you weren't aware of the difference) words are used in different places.

So what do you call the stuff from a compost heap, Mark?  Or have you mentioned that and I missed it? (always a possibility!  )

[Anthony Darby]

It's just a shortening of "composted organic material, e.g. bark, garden waste etc., in a bag used for potting plants" to "potting compost".