hardboiled eggs, pasta all kinds of stuff. just make sure it or YOU have not added ANY salts to it at all while cooking man
Just like potato water, rice water also contains valuable nutrients for houseplants. Using it is also a wonderful way to conserve water and a great way to take some of the worry out of over-fertilizing. The starches from leftover rice water will help encourage beneficial soil bacteria, while the vitamins and minerals will add small amounts of NPK (nitrogen, phosphorus and potassium) to the soil. One thing to keep in mind when using water from cooking on your houseplants is to make sure the water has cooled to room temperature before you use it. It's also best to avoid using water that you have added salt to. Just about any clear or light-colored water that is left over after cooking is probably okay to use as long as it doesn't contain salts. This includes using water from cooking hard-boiled eggs, pasta and vegetables. If you have a freshwater fish aquarium, save some water for your houseplants every time you clean it.
I dont entirely agree with the aquarium theory although it does work, just in a living soil I know PH acids can be added to the water for freshy fish. or used to anyways. I had one many many yrs ago. but other than that, I agree totally. nice post I was reading.