Compost Questions and Answers     
What	is	compost?
Compost is a natural humus-like soil amendment that results from 
the controlled aerobic (with oxygen) decomposition of organic 
materials.  Compost is not soil – it should be mixed with soil.  It is 
not fertilizer, although it contains many slowly released nutrients.  
What	materials	(“feedstocks”)	are	used	to	make	compost?
Compost facilities in Washington recycle a variety of organic 
materials, including yard debris, food scraps, manure, biosolids, 
forest residuals like sawdust and bark, construction wood, and 
agricultural residues.  All of these materials can be used to produce 
high quality compost.  Your supplier can tell you which materials 
they compost.
How	do	I	know	I’m	getting	safe,	quality	compost?
Fortunately, in Washington we have strict permitting and production 
standards for compost facilities, that include both time and 
temperature requirements and contaminant limits.  
What	about	weed	seeds,	plant	diseases	or	pesticide	residues?
The controlled time, aeration, and temperature process required in 
Washington has been shown to kill weed seeds and plant diseases.  
That same process breaks down most pesticide residues.  There are 
a few agricultural pesticides that are not easily broken down, and 
permitted Washington compost manufacturers carefully watch their 
feedstocks to keep those materials out of the composting process.
Compost Beginnings
The yard debris or food scraps* that you 
place into your home compost bin, take to 
a drop-off site, or set out for curbside 
collection could become the compost that 
you later use on your garden, lawn, and 
flowerbeds.
It is essential to place only quality organic 
material into the composting process.  Here 
are some tips:
l	The products you use or spray in your 
yard can end up in the compost process.  
Carefully read the labels of pesticide and 
herbicide products you use. (See page 9.) 
l	Please keep yard debris free of :
	 x	Garbage
	 x	Plastic of any sort
        - Plastic plant pots
        - Plastic plant tabs
  - Plastic bags (if you want to bag 
      your yard debris, use paper
      garden bags - available at most
     garden centers)
		x	Rock, brick, or masonry
		x	Glass or metal
		x	Pet waste.
* Many localities now collect food scraps and 
food-soiled paper along with yard debris for 
composting.  Call your local collection service 
to find out what is collected in your area.