When I started making HM detergent, I read somewhere that citrus oils can stain clothes so I have always avoided them (even though I love citrus oils, and they are cheap). Can anyone here clarify whether that's true?
For my laundry powder I usually add 10 drops of lavender and 5-10 of tea-tree oil. It doesn't really scent the clothes but I like to think that maybe it neutralises bad odours a bit, and possibly even contribute some antibacterial/antifungi properties - perhaps the quantities are not enough to do anything at all, but as DeeAnna says, it smells nice when I open the tub!
ETA: Sorry I don't know how much would be needed for a 5 gallon batch, that sounds like a crazy amount of detergent! My batch size is approx 4 cups (1-2tbsp wash dose)