Mushroom compost

[angie]

A friend of mine is wanting to split a load of mushroom compost with me. I think I read somewhere that if you have acers and rhododendrons not to use mushroom compost.  Any advice please.

Angie 

[brianw]

Traditionally it contained crushed chalk, often present as white lumps you could pick out. It may be more high tech now but will still contain Ca presumably.

[SJW]

More info here: https://www.rhs.org.uk/Advice/profile?PID=294

[Maggi Young]

By the time  mushroom compost is sold off the lime content is much, if not totally reduced. We used a lot of it when remaking, along with David Atkinson, Harold Esslemont's "new" garden - when tested it was just about neutral.
 Go for it!  You'll also get a lovely crop of mushrooms to eat!

[angie]

Thanks folks .
Maggi I hate mushrooms but if any do grow they will be bagged up and chef Ian can cook something nice for you .

Angie 

[Maggi Young]

 

[Paul Cumbleton]

Angie, Not all mushroom compost these days has lime added. We have a local supplier of it without lime and it comes out around pH6. So it would be worth checking with wherever it is you propose buying it from and asking if they know its lime content and pH.

Paul

[angie]

Thanks Paul . Think my friend is getting the compost from CPA horticulture so will have a look on the web site.

Angie 

[Jacek]

As a child I used to live in Warsaw in an apartament house with inner yard-  a kind of simple garden. It was said the garden was fertilized with mushroom compost many years before. During all my childhood I was collecting mushrooms and eating them, driving my mother to fury due to  sanitary issues, you can imagine - dogs, cats  etc.

Angie I warn you - you may have to eat mushrooms for years!

[angie]

Hopefully there won’t be as much calories in mushrooms as there is in chocolate 
Angie 

[ArdfearnAli]

I remember speaking to a local peat supplier who supplied the peat for the top lair of mushroom compost. It was very acid black peat and they used it as a casing. Depending on where it is sourced from the top casing has a fair amount of lime added. It can come from either limestone (calcium or magnesium and in quite a lot of cases calcium lime reclaimed from the sugar beet industry. The ideal ph of the casing is around a ph of 7-8 which can be different to the compost itself. I would think as Maggie pointed out the lime would have been neutralised but if there is a percentage of calcium left it may not be suitable for ericaceae? Might be worth doing a small trial with it to check before using it near acid loving plants. I find that the ph test kits available give you a rough idea if its very alkaline or very acidic but aren't that accurate.

Alasdair

[angie]

This is the details on their website
pH Level: 6.5 -7
Organic Matter: 66%
Ammonia: 0.26%
Magnesium: 0.4%
Nitrate: 0.08%
Phosphorus: 0.6%
Potassium: 3.1%
Total Nitrogen: 2.4%

Alasdair I do think it’s a good idea to test the ph when it comes. Luckily enough I have a really good testing kit that I use for my koi so will do this when it arrives . Thanks.

Angie