How do you make your choice ?

Avoid the garden soil. It will probably set hard in a pot, or not drain very well; its likely to have weed seeds in it too. Your best bet is to buy Multi Purpose Compost from the Garden Centre; that should have been sterilised to kill the weed seeds,, and should contain enough nutrients to sustain the plants [without additional feeding] for about 4 weeks. There is some rubbish about though ... a good garden centre will have an open bag for you to inspect - if its full of twigs and lumpy bits its best avoided. Should be around £12 for 3 x 60L bags. I reckon a 60L bag will fill about 40 x 1L pots (so about 20% disappears somewhere!). 9cm pots are about 0.5 L - so a 60L bag should fill 80 x 9cm pots. All very roughly and from memory.

There's a thread on Brands of Multi Purpose Compost here:
http://gardenerscorner.co.uk/forum/threads/compost-review-2013.49715/

 

Well when I went to b&q last week I bought a bag of verve topsoil to mix into my own turned over soil plus 2 bags of Miri le grow multi purpose compost I made a raised bed 8x4ft mixed it all together, the question I now have after reading from the link you provided in your last post that the verve brand of compost is for less a better word crap, so I'm wondering if the top soil is too? Also how do you David the Mirical grow compost ? Reason I'm asking is because my raised bed could do with some more substrate in and I was going to add more of the verve top soil plus a bag of horse manure to fill it up a bit more would this be a good move ?

 

Ment to say rate miracle grow compost don't know why David came up .... Haha

 

They'll both be fine mixed into your raised bed. I think its only as a potting compost, and even more so as a seed sowing compost - i.e. to start seeds off in containers - that folk have found it performs badly. Mixed into the soil it will add body, humus and so on which will all help improve the soil structure. In fact pure Moo Poo will also do that although it needs to rot down in a heap for 6 months as its not good for plants "fresh". And if your local supplier doesn't have it properly labelled and their Moo Poo is in fact 100% Horse Poo that's fine too - some would say better, in fact. Any riding stables near you? Worth asking, many will let you have it for free, you just have to bag it up yourself.

You got a compost heap? That will give you plenty of top-up material (in a year's time, if not before). Many councils provide subsidised-price compost bins if you fancy a pre-made one, otherwise a common solution is to strap some pallets together to form a hollow cube.