I saved up my dishwater in a tub in the sink, and was able to fill up a gallon jug twice with that.
The third gallon was from 2quarts of dishwater I saved from the
Wash Dishes by Hand BB, and an additional 1/2 gallon of dishwater from washing some spare dishes today.
I gave it all to some landscaping plants outside my apartment.
I used
Castile Soap.