Category Archives: FAQ’S

What about noxious weeds?

Does West Marin Compost accept noxious weeds, and what happens to weeds in the composting process?

WMC does accept almost all “weeds.”  Except for Tim.

In all seriousness, most weeds and weed seeds are destroyed by the high

temperatures of the thermophilic composting process.  One notable exception is

the seeds of common garden morning glory (Convolvulus arvensis), which have

 been shown to survive temperatures of up to 180 F.  Consequently, we do not

accept this material at the drop off site.   

Most other plant material is accepted.


How is the compost made?


Dairy manure separator solids are combined with approximately equal volumes of green and equestrian materials, formed into windrows on the composting pad and watered as needed. Any runoff from the compost area flows to the dairy’s liquid waste storage ponds. Windrows are managed in accordance with CAL Recycle (and Nicasio Blend under the USDA National Organic Program (NOP)) guidelines to reduce pathogens and weed viability to negligible levels.  A mechanical screen is used to separate coarse from fine material at the end of the process.



How is compost better than liquid manure?

Because finished compost is a dry material (typically less than 50% moisture at maturity, it is less costly to spread than wet manure (typically 75-95% water). Finished compost is odorless and the nutrients it contains are much less mobile under rainfall conditions than manure.  In fact, compost is often used as an erosion control material to help prevent soil movement on disturbed sites. Properly composted material does not contain viable weed seeds, which liquid manure often does, so spreading compost does not spread thistles or other weeds.

When is the drop-off site open?

Drop off site is open Monday through Saturday from 7:00 – 3:30 and by calling 415 662 9849 for assistance.

You now can also purchase composts and mulches at the site. See the Products page for a description of our diverse line of soil amendments.

Clean green material and wood scraps only will accepted at the site.