Submerging weeds in a bucket or barrel of water to rot is a common approach used across the world. Many Australian’s would refer to this as “Weed Tea”.
Natural Farmers around the world also use this technique, but they typically add extra microorganisms to the brew in the form of a handful of compost and/or healthy soil from their farms. In Korea this is called JADAM Micro-Organism Solution (JMS). Suburban Gardeners can do exactly the same thing to speed up the decomposition of the weeds and add additional microorganisms to their soil.
Weed Teas are brewed until the weed completely breaks down and is no longer viable. At that point the remaining solids can be placed in compost bin. Although in some countries the material is never removed and is left to rot away entirely. The process can take several months and the result is almost always stinky. Weed Teas should be diluted until they look like a weak brew of black tea. They can then be applied safely onto soil and plants. It is recommended to do so in the evening so improve the survival of the microorganisms that are present in the brew.
Plants with a known herbal quality can be particularly useful in such brews. Stinging Nettles and Comfrey are old favourites as they are rich in beneficial properties.