The Composting Process 
Even though there are a variety of composting methods, most 
composting follows a similar process: 
1.  Grinding Organic Materials: 
Depending on the facility, the feedstock (material) available, and 
the desired compost product, different combinations of materials 
are added together and ground into small pieces:
 •   Nitrogen-rich materials (such as grass, fresh plant      
     cuttings, biosolids, and manures)
 •   Carbon-rich materials (such as dried leaves, woody  
     materials, and straw).
2.  Heating Up:
The material is placed into piles where it begins to heat up from 
the biological activity of the compost microbes.  Typically, com-
post temperatures are required to reach at least 131 degrees F in a 
specified time period in order to destroy weed seeds and patho -
gens.  The compost is turned or aerated, allowing the composting 
microbes to breathe.  After a period of time, the nitrogen-rich 
material is depleted, the biological process slows, and the hot 
compost begins to cool.
3.  Finishing:
Typically “finished” compost has undergone a series of steps to 
ensure maturity and stability.  The cooling compost is aged, which 
allows the decomposition process to slow down and the finished 
compost to stabilize.
The end products you purchase may be entirely compost, or a 
combination of compost blended with uncomposted additives 
(such as peat, bark, minerals, or soil).
Applications for Compost 
Planting	New	Garden	Beds	or	Lawns
Spread a 2-4 inch layer of compost and mix into the upper 6-12 
inches of existing soil: use more in sandy soils, and less in heavy clay.  
Reapply ½-1 inch annually on garden beds.
Mulch	(surface	applications	on	landscape	beds)
Spread a 1-2 inch layer of coarse, woody compost.  To allow proper 
airflow, it is best not to pile mulch around the stems of trees and 
shrubs. Pull mulch 1-2 inches away from stems.
Top	Dressing	for	Lawns
Spread a ¼ to ½ inch layer of fine screened compost, and rake it into 
the lawn.  For best results, plug-aerate the lawn before top-dressing.  
Overseeding at the same time will thicken thin patches in lawns.
Blended	(Manufactured)	Topsoils
Good quality “topsoil” products usually include 10-40% compost by 
volume, mixed with a sandy loam soil that allows good drainage.  
These compost-soil blends help establish healthy lawns and gardens.
When to Use Compost?
 • Any time you’re preparing soil for planting
 • Mulching beds and gardens in spring, summer, or fall
 • Top-dressing lawns in spring or fall.