Even when managing for rats, the composting process must be the priority! In order to avoid potential problems—including attracting rats—the composting process has to drive our management and site plans, not the other way around. This presentation covers tips for optimizing the composting process and considerations for compost site managers.

1. Linda Bilsens
Project Manager, Composting for Community Initiative
Institute for Local Self-Reliance
Successful Rat Prevention for Community Composting Webinar
June 5th, 2017
Optimizing the Compost Process
to Avoid Rats

3. The Process to Further Reduce Pathogens
(PFRP)
Adapted from U.S. Composting Council, “Model Compost Rule Template” April 2013.
Average Temp Duration Notes:
Windrows: ≥ 131∘F ( 55∘C)
≥ 15 days, non-
continuous
During this period: ≥ 5 turnings, with ≥ 3
days in between turnings.
Aerated Static
Piles or
In-Vessel:
≥ 131∘F ( 55∘C)
≥ 3 days,
continuous The ≥ 14 days at ≥ 113∘F follows the ≥ 3
days at ≥ 131∘F
≥ 113∘F (45∘C)
≥ 14 days,
continuous
Compost processing time and temperatures should be sufficient to
kill weed seeds, and reduce pathogens and vector attraction.

4. Optimal Conditions for Composting
C:N Ratio 25 - 40:1
Moisture 50 - 60%
Temperature 131° - 153°F
Oxygen 5 – 10%
Particle Size ⅛ – 2 in.
Initial Bulk Density < 1,100 lbs/yd3
pH 6.5 - 8
Image: Composting Fundamentals, Whatcom County Extension
Table adapted from On-Farm Composting Handbook, by Natural Resource,
Agriculture, and Engineering Services (NRAES) Cooperative Extension (June 1992)
Hot core!
O2 O2
Water Vapor Heat CO2
The Compost Pile “Chimney Effect”

5. Proper Storage for Every Step of the Process
Real Food Farm’s Compost Co-op System in Baltimore
Lockable bin
for Browns for
community
drop-off
(Leaves)
Lockable tumbler for
community food scrap
drop-off
Lockable bin for Co-op
tools, incl. scale and
data logs
Lockable 5-bin, rat-resistant
composting system for active
& curing piles

6. Considerations for Bin Systems
Design by Urban Farm Plans (www.urbanfarmplans.com)
http://dpr.dc.gov/service/community-compost-cooperative-network
Raised off the ground for aeration
and less protection for animals
Enclosed in ½” hardware cloth
Paver stone-lined floor
Mixing bin & tarps used at
the DPR Compost
Cooperative at Howard
University
No warped slats, no gaps, no loose corners

7. Protecting Curing and Finished Compost at
the DPR Compost Cooperative at Howard University
Hardware cloth ”curing corral”
on pavers, secured with zip-ties,
and covered with agricultural
cloth
After sifting, finished compost is
stored in re-purposed tumblers
A recent rat-proofing retrofit:
adding gravel under and
around pavers that the
corral sits on

8. Management Considerations
 Monitoring: Check your compost
regularly!
 Act on your observations: Don’t let small
problems become big ones.
 Training matters: Train your people!
 Communication matters: Be accessible!
 Clean up nicely: Site hygiene is key! Informational signage at Real Food Farm in Baltimore
Observe, record, take action, repeat!

9. Planning Considerations
 Your microbe allies have predictable needs,
how will you meet them?
 Create a monitoring and management
schedule that meets these needs!
 What schedule can your dependable labor
force handle?
 What amount can your system handle?
New members of the Real Food Farm Compost-Coop get trained on the procedure for dropping off food scraps, recording
weights, and turning piles.
The Compost Food Web
NRC, 1981a

10. Set yourself up for success!
You need space:
 To compost
 To store browns (carbon source or
bulking materials)
 To store temperature probe, scale,
recording binder
 To cure
 To screen
 To store finished compost
 To handle water
 To move around
 To breathe
To view the supporting resources for this webinar, including ILSR’s draft Best Management Practices for Community
Composting, visit https://ilsr.org/successful-rat-prevention-for-community-composting-webinar/