Mulching with Weeds


Posted by Horticulture Guy - Peter Punzi | Posted in Northwest U.S. Gardeners | Posted on 11-08-2012

Q. Your web site is very informative and inspiring. I try to follow your advice as much as I can.  We had good year so far..specially in green house..lots of cabbage, cauliflower,  salad, lots of peas and lots of tomatoes are coming…My question is I have lots of weeds in my garden.. what I used to do is to collect all weeds and mulch it with my lawn mower and mulcher.. and put it back into garden..Now I think I am putting back the weed seeds as well.. how I can prevent those seeds from growing.. or how to kill the seeds naturally before I put em back again..?

Thanks again… ~Vik ,Snohomish, WA

A. To kill the seeds naturally you will need to compost the weeds.  There are two ways that you can compost – low and slow (sounds like Ramone the Chevy Impala on the movie Cars – my son is an avid fan)  or high and fast.  Low and slow means low temperature and maybe a year to process the compost.  This will not remove the weed seeds or bits that may resprout.  You want high temperature (hot) which produces a final composted product in a month or so.  This is the process they use at the LRI landfill (Pierce County Recycling, Composting, & Disposal) where all the yardwaste is processed.  Low and slow is much easier as you just pile up your garden debris and turn it a few times – low key.  To get it to go to high temperatures (120°F–150°F) you have to monitor the types of waste you put in (balance of green or nitrogen rich products and brown – containing carbon like wood chips or brown leaves).  You also have to turn it regularly because the microorganisms that produce heat need oxygen. These temperatures will kill weed seeds and other structures that allow the weeds to reproduce  Rather than go into any more detail here I will refer you to a WSU extension booklet which you can download on composting.

Live Long & Garden

Peter – HG