Re: Quackgrass and Plastic Mulch

Robert:  I have used 6 mil black poly, doubled, as an edge around my 
garden, to keep the adjoining lawn (which includes quackgrass, 
originally having been a pasture) from growing into my garden.  The 
quackgrass has no trouble getting straight through two layers of 6 
mil poly, usually within a year.  However, I also use black poly (one 
layer) as a surface cover to kill off patches of garden that have had 
a history of grass encroachment.  I typically leave it covered for 
about two years, although I have not tried any shorter period - might 
still work.  This works very well to kill quack and other perennial 
weed species.  I then open it up in the spring, let it dry out, and 
till it a few times before making beds and planting.  I allow any 
residual perennial weed growth time to happen - and work it out 
manually - before making the beds and planting.  There is typically 
very little life left in the quack after two years in the dark, but I 
want to be sure there is none.  Having a little bit of quack grass in 
my garden is like being a little bit pregnant!

I remember a humorous (I hope) quote from a couple of organic 
gardeners, that they removed quackgrass rhizomes etc. manually by 
screening sections of the garden, one at a time.  They then let the 
rhizomes dry out and burned them, being careful where they put the 
ashes!  Ann

Dr. E. Ann Clark
Associate Professor
Crop Science
University of Guelph
Guelph, ON  N1G 2W1
Phone:  519-824-4120 Ext. 2508
FAX:  519 763-8933