Pucky,
I've found that the original Burmese genetics (one of the oldest pure Sativa strains) give me the highest yield for my climate, since I don't have the extended flowering season that people living further from the ocean have access to. I need a strain that can realistically produce three pounds of raw, wet bud per plant on two gallons of water daily, by the second week in September, any longer and I'm risking bud rot from the morning fog. Of course the problem with the pure sativas is that even with horizontal training you're stuck with plants that grow to 10-12 feet and waste a ton of nutrients supporting the long node spacing.
Obviously I've had to cross in some Indica genetics in order to keep the plant size more manageable and give people that couch potato high that makes the bud fly off the shelves. This year, a third of my plants were the original '420' strain, which is 50/50 Burmese crossed with Fuckin' Incredible (famous pure Indica, probably the most expensive genetics on the market right now) and shows awesome hybrid vigor. The more Indica you introduce though, the more problem you will have with pests and disease, that's just the nature of growing Indica outdoors. To protect my yield in case it's a bad year for either pest or disease, the other two-thirds of the plants were split between Nuclear (Timewarp x Burmese) and Passionfruit (Grapefruit x Burmese). Both of those are between 70-80% Sativa and give me a super hearty crop while still topping out at a manageable eight feet tall, and taste sufficiently different that I can accommodate most general preferences of my patients.
I try to grow a max of three strains each year because you can only tolerate so much variation in the growth patterns of the plants. That's why all my starts are clones (not to mention my seed company charges $85 for 10 seeds when I need to grow new mothers), so that they all come from the same plant and will grow the same way at the same speed. You guys have no idea the intricacy involved in maintaining 100 plants that are 8' tall and 8' in diameter (roughly the size of a fluffy Christmas tree), even when they're on the same growth cycle.
