Quality of bought compost

[rob the roller]

I have always bought the cheapest available multi purpose compost, usually paying £10-£12 for four 70 litre bags. I reckon to buy at least 12 bags, sometimes as many as 20, through the season to augment the compost I make myself. Compost is essential on my very heavy clay soil.

The price per litre hasn't changed much in the last 5 years or so, but the quality of the compost does not seem as high as previously. The MP compost I used to buy was fairly consistent and friable. The present lot is lumpy and contains wood and other less easily identifiable lumps that have not composted down. Root balls don't seem to form as well around the young plants even after it has been sieved.

Does anyone know the difference, if any, between the cheap composts and the higher priced ones, and whether there is anything to be gained in spending more?

[crichmond]

I have also noticed the quality of compost seems to have dropped, I even got a couple of bags of Miracle Grow MP and that had bits of wood and small peices of branch that were not composted in it.

[rogesse]

Interesting - I've had the same problem. Apparently compost deteriates with age, perhaps it was old stuff being sold?

[Duronal]

for what it's worth i believe that Which? found that many of the peat free composts outperformed the peat based composts when looking at young plant growth and root forming (this wasn't the case with germination). Maybe some of those might be worth a try.

Another source may be to look if your council offers any composted materials. I know that some councils offer compost in bulk and normally at a competitive price.

Hmm apart from that i have also noticed that there seems to be a lot of wood in my MP too.

[baggyman]

I think there are some dodgy suppliers about..... I heard of one major diy chain selling compost made from shredded up kichen work surfaces with soil added to it!
Don't know if it's true or not but the bloke who told me said you could see small lumps of the plastic/formica stuff in it.
Then there's all the local recycling centres who make compost from garden waste and heaven knows whats in that, Mare's Tail, Club Root, Diseased plants etc

[Toby]

Then there's all the local recycling centres who make compost from garden waste and heaven knows whats in that, Mare's Tail, Club Root, Diseased plants etc

This type compost is made in huge amounts and cooked at hundreds of degrees, so all bacteria and diesease is killed off. don't know whether it still hold lots of nutrients and stuff though

I have also noticed that a lot of compost at the moment has a lot of wood. Its not going to be a problem if its dug in to soil as it will break down, but probably not to good for sowing seeds i would have thought

[Demeter]

Me too. We all moan about the quality of peat free compost having lumps in but this year I have noticed that the peat-based MP composts seem to be quite lumpy as well. A case of the makers being less fussy about the amount of woody items that go in, and perhaps not giving it long enough to rot down properly? Fingers crossed, but not noticed any problems with the actual plants, only that the compost has lumps in. Switching over to peat free this year so can hardly complain about lumps anyway!....

[Maximillian]

i asked my daughter to buy me westland compost for my birthday as homebase were doing an offer. more expensive but a really lovely dark compost with hardly any woodchip. not sure about the peat free bit though..eek. the last time i bought peat free compost it killed my courgettes. too strong maybe?

[Maximillian]

BTW is anyone else as sad as me asking for compost for my birthday ;¬)

[COMPOST CORNER]

for what it's worth i believe that Which? found that many of the peat free composts outperformed the peat based composts when looking at young plant growth and root forming (this wasn't the case with germination). Maybe some of those might be worth a try.

.

Does this mean the "John Innes seed" soil based compost I bought at the weekend isn't good for germination?
To be honest, it looks like a bag of any old soil, and it's moisture retention is awful.

[Snadger]

Does this mean the "John Innes seed" soil based compost I bought at the weekend isn't good for germination?
To be honest, it looks like a bag of any old soil, and it's moisture retention is awful.

I make my own version of John Innes 2 and 3 for potting on but rely on proprietory peat free seed compost.

[Demeter]

Does this mean the "John Innes seed" soil based compost I bought at the weekend isn't good for germination?
To be honest, it looks like a bag of any old soil, and it's moisture retention is awful.

JI seed compost isn't peat free.
It's the peat free composts that show poor germination. Although lots of people on here say that of the seeds that do germinate the plants are strong and healthy with good root formation, so it may be just a question of adjusting expectations for germination rates for those choosing to use peat free (seed is cheap, peat bogs are not, sort of thing)

Oh look (HH article on peat free seed composts, suggests making your own from leafmould) - http://www.harrodhorticultural.com/w...free_seed.html

[RedThorn]

Just to throw a new slant on this.... perhaps the compost companies have been caught with their proverbial pant's down by the sudden upturn in GYO?

[Snadger]

Even though modern potting compost appears to be very course the plants roots seem to thrive in it's open texture!
I have a small seive that I use only on the stuff I cover the seeds with and have no complaints at all and find the majority of makes gives excellent results!

[sewer rat]

The MP compost I used to buy was fairly consistent and friable. The present lot is lumpy and contains wood and other less easily identifiable lumps that have not composted down. Root balls don't seem to form as well around the young plants even after it has been sieved.

Does anyone know the difference, if any, between the cheap composts and the higher priced ones, and whether there is anything to be gained in spending more?

I have used various composts - 2 pallets per year - for the last three years.
The ones I have used are as follows
Foremost MP - peat based, very little waste material, contained wetting agent.
Humax MP - peat based, even less waste
Little Gem MP - peat based, loads of waste
Mother Earth MP - peat based but states peat not taken from any conservation areas or SSSI's. No waste at all (so far) but does seem to dry out a lot quicker than either Foremost or Humax.