I used last year Westland for pots and containers with added John Innes, did well last year doing the same again this...so far so good. I don't like the water retaining gels/crystals.

I have just had a phone call from Miracle Grow.
They deny that it is a fault of their compost, they say that the mushroom spores are in the air and have now started to grow in my pots. Ummmm strange it is only in the Miracle Grow ones
However as a gesture of good will they are sending me some vouchers to spend on their other products.
I didn't expect to get anything in return but I ain't going to turn them down

..me too , I go for the special offers and buy the cheap ones then add organic plant food and blood and bone

I needed lots this year because I have put some raised beds in to grow veg.

Maybe their compost had mushroom magnets in it
Have fun spending the vouchers

I buy the 120L bags even though I can hardly lift them and aim for peat-free if I can. I use moisture sponges in hanging baskets and miraclegrow's granules in the pots. I use ericaceous compost for acid-loving planting eg hydrangeas, acers, cameleas etc and add organic chicken manure pellets to the soil and feed with sulphate of potash when required.

Haven't used my vouchers yet but the mushrooms are still coming in my pots
Heres one I found today;



And a close up;



I don't think it's edible though.

Aha! That looks like the Lesser Spotted Miraculous Grower

No idea if that's edible, I wouldn't risk it.

Don't worry I'm not going to!
My son often accuses me of being on the magic mushrooms