I make compost by cutting and mulching up the foliage of soft-leaved plants, including vegetable crops which have finished producing and which may, or may not, have been allowed to run to seed.
This method of making compost (of which more at another time), obviously doesn’t produce temperatures high enough to kill seeds. I’ve decided that on the whole, this is a Good Thing, provided I don’t compost anything containing seeds of plants I don’t want (aka weeds).
When I prepare an area for planting new seedlings I generally put a few inches of fresh compost on the top of the soil. This often results in an interesting crop of volunteer seedlings which can then be harvested or transplanted somewhere else. The only thing I have to do is make sure the planted seedlings don’t get totally swamped by the ‘invaders’. Sometimes I think all I need to do to get an edible crop of something is to spread the compost, water and wait.
For example, this year’s crop of garlic cloves (deliberately planted) are now surrounded by seedlings of carrot, lettuce and bok choi (chinese cabbage), which are providing a useful harvest. When they’re all gone, the garlic can claim it’s rightful place as the sole occupant of the bed.
Seedlings which came up in the compost. The garlic’s in there….somewhere