So my friend grew cascade hops in his backyard and wanted me to brew something for him with them. I have one question. With homegrown hops how do I know the AA%? Or do I just wing it? Any advice? The picture is of the hops. Those are gallin size and over a pound in total.
You won't know the alpha acid percentage precisely unless you send them to a lab. You could either wing it by making a guess based on the usual percentage of alpha acids for cascades, or you could use a commercial hop for bittering and save the homegrown hops for your late additions and/or dry hopping.