Um, could you be a little more specific than "cleaning powder" please? Laundry soap? Cleanser with bleach? Polishing compound?
Best to look on the label and see what the ingredients are, first. (please tell us, too) You can also Google the Manufacturer's Safety Data Sheets for most products and see exactly what's in it and if it is toxic in any way. Just enter the product name, with MSDS after it, and it should appear.
If it's some sort of soap, I wouldn't think a T. to 5 gallons could possibly hurt the plants or you, especially if you further diluted it. Soap is commonly used for insect control, so you may have killed off some bugs in the soil, but they'll probably be the only casualty.
