Why are you guys growing San Pedro from seeds and not buying cuttings or full cacti from a cactus grower? You'll have at least 3 to 5 years from the time you plant them before you harvest... In my experience just a little bit of looking will find you what you're looking for.
I started growing cacti from seeds just for the pleasure of growing them. I started them about seven years ago, and now I have about a dozen five foot cacti. They'd be even larger if I had planted them in the ground, but I've moved a bit over the past five years so it's not really practical.
The ironic thing is, even though now they are old enough to harvest, I'm not sure if I can bring myself to chop one of my cacti down to eat it!
For me, it has turned into a sort of life-long hobby.
