I put a TBS or so per 5gal of water for outdoor plants. I do this about every other week unless I feel the plants need more. I really don't check my Ppm outdoors because I'm so used to mixing the correct amounts. I check my PH every fertilizing outdoors but that's about it. I really check the ph and ppm more indoors, but once I know the ppm rate I usually don't check until I raise the amount of ferts I add. But a TBS or 2 per 5gal of water is good outdoors unless your having a serve problem.