That's an excellent question to ask your allergist/health-care provider.

I usually pull them out and throw them in the compost pile, but I don't know if it really matters. I found some in the mulch nect to my daughters sand box that were rather phallic looking it was unlike any mushroom I had ever seen. I definitely felt I needed to remove it before my neighbors started making too many jokes about what I was growing these days.

i had great luck with Mel's mix last year. so far, so good this year. i didn't use mushroom compost last year, though i am trying some in 1 of 6 boxes this year. i think i had a few mushrooms grow last year under some plants when we had a lot of constant rain. they were only where it was damp and shady, so i am not totally surprised. it only happened that one time. personally my compost mix was a blend of what i could produce at home (leaves, grass, vegetable scraps) supplemented with some from nurseries. i pretty much stayed with the plant composts. i'm vegetarian and didn't really want to deal with cow or chicken waste mixed into my food. i have a bit of paranoia about what those animals are fed and what comes out. that's just me, but even with my relatively selective compost mixtures i got great results with Mel's Mix. the soil in my yard is not any good for growing (clay) and this is a lot easier than trying to change the ground. one thing in support of Mel's Mix (for the suspicious types).... got to any garden place and look for the (organic?) Miracle Grow garden/vegetable soil. if you read the ingredients you will see that it is not "dirt". it's a roughly even mix of peat moss, compost and perlite. perlite is similar, in function, to vermiculite. the square foot gardening site and books have a lot of their explanations as to why they feel vermiculite is superior to perlite (basically it holds a lot more water). anyway..... the point is that one of the biggest commercial sellers of gardening soil is basically selling some that is very close to Mel's Mix in ever gardening center, hardware store, Walmart etc across the country. if you have a need for any substantial quantity then you can see how much cheaper it is to make your own mix. i have not had your issue with the plants being yellow. as far as i know they all seem healthy. some plants seem to be slow to grow at first, but other are not, so i am guessing it's just that plant? i do not have a lot of years experience, so i can not compare it to proper traditional row planting. that was always a mess for us (due to clay like soil).

I just kick them over with my shoe. By the next day they are brown and we just mow them and mulch them with the next mowing. They aren't harmful. Some of them are pretty cool looking. I was working in my garden by the front walk last weekend and I had 2 huge ones growing among the rain lilies. A lady walking down the street remarked how beautiful they were. She thought I was cultivating them. One persons unsightly could be another persons beautiful. Made me look at them in a new way. I let them stay till they turned brown, and then picked them out and threw in the compost.