Dear Keletso Seetseng,                                   Dated March 11th, 2015

Congratulations Keletso for realistic considerations about the local problem. Work locally and extend your concepts Globally.

My suggestions are the followings:

(1) Weed seeds are really a problem and will remain viable in ordinary vermicompost beds where there is lack of knowledge on grass seed biology. The Earthworm people think that the animal could do any thing and everything. The seeds will be inactive at > 60 degree Centigrade.

(2) My humble advice to you will be to make an intervention of an anaerobic phase, may be for about a week in in-situ condition either in polyethylene packet, plastic or metal container, or cemented tank, or may be in pit covered with black polyethylene. You have to make the system airtight.

(3) Try to look into the C/N ratio to monitor the time period.

(4) I am adding another part of the answer to your Vermicomposting system, that is always go for the local species of earthworms which are suitable for your system and could contribute in sustainable manner.

(5) Do not be washed away with exotic, non-native species of earthworms which will be harmful for the local  soil carbon status and soil biodiversity, even for the associated plants. Please try to read papers on the impact of invasion by exotic earthworms.

All the best and shall be happy to know your efforts,

B. K. Senapati

i am very thankful for the answers

Heat treatment can indeed be effective in neutralizing weed seeds, but this requires sustained high temperatures, which would likely harm or kill the worms. A couple of other possible controls are: (1) try to cut the grasses before they go to seed; and (2) applications of corn gluten meal are now used widely in Ontario to prevent emergence (i.e., germination) of annual weeds. In the latter case, timing of the application is key because if applied after germination has occured, the corn gluten meal is also an effective fertilizer! It does not work on perennial weeds, either.