Building Rich and Healthy Soil 
With Compost
To grow healthy plants you need healthy soil.
Healthy Soil:
l Is teeming with life!  Healthy soil is a miniature ecosystem.    
 A teaspoon of healthy soil will have upwards of four billion   
 tiny organisms which recycle nutrients, suppress disease, and  
 discourage pests.
l	Retains moisture but allows drainage.  Healthy soil has        
 structure that allows water to drain through, retains moisture,  
 and promotes strong root growth.
l	Is full of organic nutrients.  Plants depend on the micro-      
 organisms found in healthy organic-rich soil to provide   
 nutrients to their roots, and help them thrive.
A healthy garden and landscape is naturally resistant to pests, 
drought, weeds, and diseases.  Maintaining healthy soil may allow 
you to reduce use of chemical fertilizers and pesticides.
Soil	is	a	planting	medium.		Compost	is	a	soil	amendment.
Do	not	place	plants	directly	into	100%	compost.
Ask	your	supplier	or	see	next	page	for	mixes	for	different	uses.
Washington State Encourages the Use of Compost, 
to Protect Our Water Quality
The Washington State Department of Ecology recommends that soils 
on construction sites be restored with compost before planting, and also 
encourages the use of compost for construction site erosion control, to reduce 
stormwater runoff and help keep our rivers, lakes, and Puget Sound clean.  
Learn more at www.SoilsforSalmon.org	or	www.BuildingSoil.org.
Selecting Quality Compost
Compost is available in many product types and blends that may be 
used for different gardening applications.  The type of feedstock, 
the composting process, and any supplementary additives determine 
the end product.
Many facilities offer a variety of blends based on compost, such as 
garden mix, potting soil, planting mix, mulches, turf top-dressing 
and soil blends.
What to Look for in Compost
For most compost applications you will want a finished product that 
has matured and stabilized.  Look for material
	l	with a dark, crumbly texture
	l	with a mild odor 
For most compost applications you will not want compost that is 
extremely dry or wet, or extremely hot.  (Note that it is okay for 
compost to be warm and to give off some steam and mild odor.)
Quality Testing at Composting Facilities
Feel free to ask your compost provider if they have a quality control 
program, and ask for test results.  Compost facilities in Washington 
are permitted by the Department of Ecology and must meet 
standards for both the composting process and contaminants, 
ensuring a quality product.  Some facilities also participate in the 
“Seal of Testing Assurance” (STA) testing program.  See 
“Resources” on page 11 to learn more.
Remember:  
Your	compost	provider	can	help	you	pick	the	best	compost	mix	
for	your	needs.