This question confuses me. There is not a such thing as mid grade pot IMO. Most pot that you buy on the street that is called mid grade is such a grade due to usually being pulled too early, dried too fast and packaged wrongly. It makes for a inferior product. When you grow it yourself, take care in the drying and curing and packaging you end up with a quality product. As for strength...I'm a med user. I want it as strong as possible. The reason being that the stronger the product, the less I need to use for pain relief. That means less tar and other carcinogens enter my body when i smoke it. Off hand I don't know of any low THC strains. It's not something I really look at when deciding what to grow. I can control how much it effects me by how much I consume.