Mushroom Compost

[flyfiishn]

Hello All.

I have run across some compost that is for use on a local mushroom farm and they told me to use as much of it as I would like in return for some walnuts I gave them. To clarify, this is brand new, unused compost. I believe he said in their mixture they use mostly chicken manure, crushed rice hulls, rice straw, potash and some lime and gyp. Not sure on the percentages, and they are probably unlikely to tell me as its proprietary.

My question is, how much should I use in my beds. I am thinking 50-50 mix in with my existing soil to avoid using a compost that may be "too hot." Also, I am wondering when I should begin mixing it in..... now or around plant time in Mid April? I currently have a little vetch seeded into the topsoil that I plan on tilling in around march as well.

any advise is welcome!

thanks all.