IMO you are over thinking things if growing outdoors "au natural"... Mother Nature has a way of doing things. Especially if you are growing outdoors in an Organic Manner...in an indoor enviroment using Chemical Nutirents, ph is very important. Once you go over to the world of organic growing you depend more on micro herds to do the work of breaking down the nutrients into something useable for the plants. Your outdoor soil seems pretty neutral considering 7 is a neutral number. If you are doing things organically and hve a good micro herd going you shld be fine. Jmo