On 11/09/2011 09:09, AL_n wrote:
Can anyone offer any suggestions on how to kill off any seeds dispersed
within home-made compost?

Simplest solution is make sure your compost heap gets *really* hot above
70C will see of almost everything.

I have a large compost heap made from weeds and long grass, among other
things, and probably contains a lot of unwanted seeds. The large heap is
now about three months old and has been turned twice. Perhaps some of the
weed seeds have now been destroyed due to the heat generated within the
heap, but past experience causes me to suspect that many will not have been
killed.

I plan to use the compost to create a new lawn, using grass seed, in an
area where the soil is very poor. Last time I did this, the weed seeds
within the compost were prolific and started to sprout after the compost
was spread on the ground.

They will. Many are at least partially light activated and remain
dormant until they see light. Your best bet is incorporate it into the
ground leave enough time for activated weed seeds to germinate and then
hit it with a kill and deactivate weedkiller. Then sow your grass seed.

I'd be inclined to use commercial weed free compost or leave a fallow
period of 3-6 months to zap all the latent weeds if using own compost
with known weed seed problems. I tend to have the opposite problem of
compost heaps conflagrating leaving a small heap of ash. YMMV

Regards,
Martin Brown