We have moderately sized (under or around 0.5 m3) backyard composter. It is of simple cubic form with hatches at the bottom where the ready stuff is being taken out. Mostly food scraps go in there, but we also add garden waste, whether brown or green. Last spring I took first batch of the compost out, as it looked ready — nice, and dark.
However, as I used it in the plant containers as a top soil, some weed started to grow. I don't know what species it was, but it was some sort with a tiny light-blue flowers, looked like high-desert wild plant variety. That is, not a noxious ugly beast, but a weed nonetheless. It was uniformly distributed in the compost, and showed up nearly in each container I put it in.
Apparently the pile was contaminated by some plant that have gone to seed. So, the questions are: If I leave the pile to work longer, would it help to get rid of the seeds? Can the seeds even be decomposed, or they are too well protected? It's not that big of a hustle to weed them out in the containers, but I assume it would be a bigger problem if I spread it in the yard.