Now you're talking, if I did all that I'd average a full pound per plant, not one half pound per plant. I used to have to return all the damn time for weeding, in just about the timing you prescribe, but then I tried something new. In the fall when I turned over the dirt and added amendments I placed over the area some landscape fabric. I saved enough dirt to cover the landscape fabric with a one inch covering. Over all that I dumped a few bags of fall leaves to 1)make it look like no one was ever there, 2)hold in moisture and 3) block the damn weeds with another layer. A little dirt spinkled on top of the leaf layer kept them from blowing off during high winds. I emphasize this because grasses are so damn fast in growing back. They have roots going down up to five feet and removing them all is damn near impossible. Grasses out compete surrounding vegetation by grabbing all the nitrogen out of the soil faster than competing plants. Marijuana loves nitrogen and will be stunted if it has to compete with surrounding grasses.
I found hauling in good organic fertilizers to my great spots in the middle of nowhere was a back breaking job. I'm a bit lazy and I never hauled in enough. Then I discovered how to find great spots that don't need much help to grow great plants. I don't care where you live creek bottoms have great soil and are close to the water table. I've discovered the best time to look for new sites is mid summer. At that time of year if I come across rich thick head high grasses of multiple species I've found a great growing spot.
There are no rules of thumb of how to grow outdoors like there is indoors, because everywhere is different. Each outdoor grower learns about the envirement he grows in and finds a strain that loves it there.