Question
I usually put my grass clippings in plastic barrels that sit by the curb, on our curbside lawn, for trash pickup. Due to a great Spring for lawns (and plants!), our grass has really done well. So well that I have enough clippings to also put a couple of paper yard waste bags on the curbside lawn along with the plastic barrels.

I noticed that my grass was dying where the paper yard waste bags sit. They sit for about 20 hours each week before they're picked up. Most of the time the bottoms of the paper bags are wet.

Is there something in the bags or their content that is killing the grass where they sit? I don't have this problem with the plastic barrels. This happens to my neighbor as well and he is using a different brand of paper bag. Is it something within the bag material along with the decaying grass doing it?

Also, is the grass permanently killed or will it recover?

Thanks!


Answer
I believe that your analysis is correct.  There should be nothing in the paper which effects turf except that it blocks sunlight.  Grass, however, is a very hot material at this time of year.  It rapidly reaches high temperatures when enough mass is reached.  It breaks down rapidly and, probably, produces by products when degrading.
A pile of cut grass on top of plants will do the same thing.  I am not educated on specific chemicals or pathogens made while composting.  The combination of heat, sun blockage and by products will produce that result.  The barrels probably have an indentation on the pottom, allowing air to enter and they are thicker than the bags, keeping temperature lower.  Further, they are water tight keeping any toxins produced away from the turf.