CSU Extension does not have a fact sheet on organic weed control, so this is from my experience and the Internet. There is nothing permanent, like glyphosate, that is organic. However, 20% vinegar can be used:
"Douse weeds with vinegar and they'll be DOA. James recommends using the horticultural kind, with a whopping 20% acetic acid [grocery store vinegar is 3%]. "It's non-selective, meaning it'll kill anything green, but it's not all that effective on grassy weeds," he says. "Also, realize that vinegar is acidic, which means you run the risk of lowering the pH of the soil."" Put the vinegar in a spray bottle and be selective and don't use too much.
This article also has different organic methods of general weed control. Boiling water is another, and one that won't alter the pH of your soil, but will need to be repeated.
If you are preparing a bed for eventual planning and have a couple of months, solarizing the soil for long enough and, if it gets hot enough, will kill both mowed-over weeds and weed seeds:
(This seems to have gotten cut off, so if the link does not work, please go to extension.colostate.edu and type "solarize soil" into he search box in the middle of the page.)
Best of muck!