Difference between Multi purpose compost and soil mix ?

[Tarragon2017]

Saw both in a garden centre and was wondering what the difference was as I thought both were the same

[Penellype]

MPC doesn't usually contain soil as one of the ingredients, it is a mixture of various organic matter such as rotted wood, peat, coir, green waste etc. Soil mix will contain a proportion of inorganic soil (principally ground up rocks/sand) which makes it drain better and is heavier.

[Note:
I use the "organic" and "inorganic" labels in the chemical sense where organic contains carbon from decaying previously living matter) and inorganic does not contain carbon and was not previously alive. This has absolutely nothing to do with "organic" as is popularly used in the term organic gardening. Oil, from which "non-organic" chemicals are made is chemically an organic substance, hence the explanation.]

[Tarragon2017]

So I guess next time I should buy both and mix them

[Snadger]

John Innes compost is loam based and is usually used in large containers to add weight. The John Innes formuale is on line if you fancy trying to make your own. Just as BFB was the predecessor to Growmore, so, the John Innes range was the predecessor to MPC.

Problem was that JI compost originally used peat,(frowned on now) loam and sand.

[Thelma Sanders]

Depends what you want to do with it. You need the soil mix for pots or new raised beds on concrete, which will have permanent plants in them, trees bushes perennial flowers and perennial veg. The added soil keeps the plants happier for longer.

For short term planting, any multipurpose compost will usually do the job as long as you remember to apply fertiliser after 5 or 6 weeks, when their initial supply runs out.

The loam based John Innes (soil based) composts are numbered to explain their uses here
About John Innes

When bags of compost say with added John Innes it just means they have added John Innes base fertiliser to the bag, not that they have added any loam.

[Snadger]

Depends what you want to do with it. You need the soil mix for pots or new raised beds on concrete, which will have permanent plants in them, trees bushes perennial flowers and perennial veg. The added soil keeps the plants happier for longer.

For short term planting, any multipurpose compost will usually do the job as long as you remember to apply fertiliser after 5 or 6 weeks, when their initial supply runs out.

The loam based John Innes (soil based) composts are numbered to explain their uses here
About John Innes

When bags of compost say with added John Innes it just means they have added John Innes base fertiliser to the bag, not that they have added any loam.

My John Innes base fertiliser is just BFB!