you've answered it yourself, you cant!

The 'one size fits all' is a cheaper production system for the agri-chemical companies. I wouldnt mind betting some growers dont mind either ; plants fail so we buy more plants. It makes me cross. same with seed companies that dont check seed carefully. Oh and those growers that get summer bedding out at Easter.

sorry Ba this is one of many bugbears that I have .grrrr

I think that these companies produce these products knowing that most people will not have a clue about compost and they know that they can shift large amounts that has been cheaply produced and make lots of profit I have noticed that the more specialist compost is much more expensive this is because the market is smaller thus profit margins less I agree with sbg about summer bedding plants going out at Easter and it is the same large companies selling the compost that is selling the plants.

Two things:- one, I make my own mix, because I knowhat goes in it, and it's invariably cheaper, and, two, did you know that most ready made composts available have a very short shelf life, and that by the time we buy them they might as well be used as a (expensive) mulch. The nutrients degrade, and that process is often hurried by the conditions in which they're kept (in the sun, then the rain, then cold). About 6 weeks is the limit before it might as well be growbag material. Phil

All the above is I'm sure true but I've grown literally hundreds of thousands of cuttings and plants by division over the past 22 years using multipurpose compost some of which has been in bags over winter and I've never had a problem.

I do add 25% sharp sand for cuttings and feed the plants 3-4 weeks after potting up but other than that things have been fine.

Aah, there's the thing. You've fed it, so how do you know what it will really do for hungry plants. Plus, cuttings are best rooted in a compost with low nutrient levels. I really don't know what to buy when I need just a bag, so I always go for what smells and feels right to the touch! My Dad used to say that if you don't want to eat it because it smells so good, then it's not good enough! Luckily, it seems, his mixes were all good enough! Sieved garden compost (yep, seeds and all in it!), sharp sand, a bit of leaf mould from up the woods, and some topsoil. Never tasted it, but it smelled great! Phil

I too have used multipurpose compost for many years. I mix it with grit and add it to my heavy clay to help break it up and over the years the improvement is noticeable. I was always taught if you take it out put it back, so I do also make my own. From time to time I do buy the more expensive ones for cuttings and seeds, but overall I think the hype of 'posh compost' is over greatly overrated. I am afraid one size fits all is not the problem, its the lack of knowledge when using it.

The alpines and bulbs that I grow from seed can take two or three years to germinate so I need a sterile, weed free compost (like multipurpose LOL). After this I use my home made composts. I have used the B&Q stuff this year with reasonably OK results by adding 25% grit and 25% coarse sand. But I do wish that I knew actual the composition of the stuff. I noticed that 'soil conditioner' was not available in the B&Q store this week so I might have to use this compost on the ground :-(

I'll tag a related question on here; I recently found out that spent mushroom compost is quite acidic. If it were used for acid liking plants and general feed (eg fish meal) were added, would this make it more neutral?
I buy multi-purpose compost from a local nursery. It's what he uses, and is happy with it. I have a Sollya heterophylla that has been in it for two years now, gets fed occasionally and seems happy. It's growth this year has been excellent, with good uniform leaf colour and plenty of the small flowers. Seed wise, it's given me near 100% germination on everything, apart from the Cleomes. I guess that what I'm saying (badly) is that it's always down to advice, trial and error, but once you find something that works you stick with it.
I don't know how you have the patience to wait three years for germination - I'm getting impatient waiting for my Tacca's which only take up to three months!

Your mushroom compost advice is the opposite to mine, Meanie. I have just been back on the web again and the information that I find is that there is a lot of chalk in the compost and that it is alkaline!!!!!

The one I found said ph average of 6, which is acidic if I remember correctly. However, as you say, Google it and you come up with answers from acidic, to neutral, to alkaline! I was wondering more generally whether general purpose feed restores ph balance or not.
I'm not interested in using it, it was just a compost related musing!

Compost nowdays is made up of anything, I now make my own because I know what is in it, I will all so be getting it tested by a freind, I one worked for a animal feed company but left because of the rubbish which was being put in the feed. Compost is no differant it,s poeples waste (green waste but what ??)

Over a period of a year, I buy 12-1500 ltrs. I sow, put cuttings and pot up with it. I have no problem. But I buy focus's own make. It doesn't have the high feed in it required for plants, so I add slow release. I don't make my own, Although I make a couple of tons of compost, that's used for the borders and veg plot. I'm sorry to say, that I refuse to pay more for peat free, when it doesn't work for me. Can't get on with the stuff, so whilst ordinary is available, thats what I use.

Since i have been buying shop bought compost (3years).
One of the problems i have is with the irregularity of some.

I have been buying B&Q multipurpose peat based for th epast year(the purple bag), the reason being it was rated top in 'Which?' compost trials 2010, for 'seed sowing' and 'young plants and cuttings'. But one month it is dark brown, sweet smelling and imho quite decent, and the next months purchase was completely different, in texture and consistency, much poorer quality, lighter in colour as if straw or something of that colour had been ground in.
I also noticed the pallets at the branch i visited had a sell by date - which read 10/10. This was this month the 11/10 and the pallet was unopened, so i imagine would be sat there for a long while yet.
I have also found metal lighter tops, bits of metal, always find some plastic and have found glass in the compost, no real problem i guess but where did it come from?
At my college our tutors often recommend using shop bought sterilized compost to reduce chances of pests and diseases which i understand but the thought of what is chucked out in some peoples 'green waste' bags and therefore what is in many of these composts, is a concern.
That and the inconsistencies aswell as the marketing rhetoric used are of worry to me aswell.

I don't pretend to be an expert in this subject, but I can relate to my personal experiences. The peat free stuff pictured at the top Bulbaholic, in my view is no good whatsoever for seeds or young plants. It is full of very coarse material, lumpy and wet. I know very soon it is all we will be able to buy, so the manufacturers should get their fingers out and shred the stuff down to an acceptable medium. I too use the purple bag ( 800 ltr last year) and I sieved this myself, add sand, seed out with vermiculite on top. The big lumps left over are used on the garden. I have never considered buying special seed seed stuff because the price is ridiculous and a rip off. Its there to catch the green, green fingers.
I did buy some peat free ( pictured ) last year, as they had run out of the other stuff. When I potted on some of my plugs, they just did not grow. I ended up re planting 2 weeks later into the purple one, and they thrived.
I don't feed any of mine until they get a bloom, but this year I am considering buying some root feed.
And yes, if anyone is silly enough to buy bedding plants at easter, well, need I say anymore.
By the way, the place where you got your bag from, are doing 3 for a tenner at my local store. ( purple ones only). No doubt they are out of date, I didn't even know there was a sell-use-best before date on them . Might even report them to trading standards, if they don't give me a deal!

Well its a source of concern, potting compost - 'fings definitely ain't wot they used to be' on that score. I tried several different brands of multi purpose this year and found that Wickes own was the best, but it does have peat in it. On the plous side, though, no bottle tops, rubbish or large lumps of wood or woody fibres, so that's what I go for. Lord knows what I'd buy for seed growing now though, not something I do now I don't have my own garden as such, but I suspect I'd buy the Wickes stuff and mix it with sand/grit etc.

I use that very same compost when planting my seeds, I don't bother using "special" seed compost, and my seeds do just as well in the compost from the bag in your pictures from B&Q.

I went on to Wickes own, a couple of years ago too,and like it better than others I used to buy,as they changed so much in quality and texture,,all well known makes,available at all garden centres...wonder if they use them? More often than not,,its the offer of 3 for £10 that they promote,that sells..obviously...,whether its good or not..

A lot of very interesting reponses to the compost question.
I try my hardest to avoid using peat at all in the garden.
I much prefer to use peat free multi purpose composts and my own compost from my compost bin.
The plants in my borders and pots are doing fine with the occasional feed of liquid seaweed and finely chopped banana skins pushed into the ground around the plants.
I have used J.Innes seed composts in the past but now make my own: I seive my peat free multi purpose compost to remove the larger pieces and add sharp sand and grit. For some seeds, I have experimented with 75% sand, 15% seived compost and 10% grit.
This mixture worked really well for my hardy geranium seeds. They were potted on into my normal seed mixture of 50% seived compost and 25% each sand and grit, then potted on into 100% compost before planting out.

I might take a hint from you, Geraniumdad, and reduce the amount of compost in my seed mix even more. I think that I will still keep 50% compost for bulb seeds as they stay in the pot for a long time but I am sure that other perennials could use a weaker mix. I don't seive out the larger bits of 'rubbish' but pick them off the top of the seed mix before sowing. I don't think that it matters once the seeds start putting roots down into the compost.

I do find that the more sand there is in the mix, the bigger the root system. I have also tried putting a smaller sized pot inside the larger pot and sowing the seeds down the side. It wasn't that successful for me for some reason.
I have tried most of the big DIY chains peat free compost and to be honest they are all about the same.
My bulbils are sown in a 70%/15%/15% mix of compost, sand and grit with a layer of grit on the top. This seems to work for me.

The pot within a pot method is generally recommended for cuttings not seed sowing Geraniumdad

Yes I know, but I was trying to replicate the small cracks in rocks etc, into which alpine plant seed might germinate.

Ah... good thinking :^)

Nothing came of it really. If I do any cuttings (usually Pelargoniums), I place the around the edge of the pot. I always put about 1/2 inch of sharp sand on the top of the pot to push the cutting through, and always water from the bottom. The top of the pot is then filled up with grit and they are left in a shady place outside in the garden.
I get about a 90% success rate.