Regular seed is a big part of the size. I tried to pop 6 freebie Sinai from Real Seed Co. and 2 popped. One plant was male. The one that's left is taking care of using the tent. I've used lots of low stress training (yarn) to fill out pretty close to the corners of the tent which I couldn't have done with 2 plants. This is a semi-dwarf plant according to the seed co. but is about 4 ft tall even after being stretched out.
The autopot system works great not just for results but ease of use. Water gets added every few days. This run is half coco/ half Promix. Since nutes hang around with autopots I use Megacrop 1 part very lightly for veg. Now that the plants are in flower I'm trying Advanced Nutrients Bloom and Big Bud. Time will tell how big buds get. The plants are only a few weeks through flower now. I don't use a PH pen, power meter for light, or special water. Water gets taken out of the tap a day before use so chemicals get a chance to disappear. Pretty simple.
Different strains are interesting to me. I could clone plants for years but I've enjoyed having a variety of strains. Having a good seed co. to get seeds from is important. Good means seeds pop, give close to what the description says, and seeds aren't too expensive. I've found a few companies I like, all with regular seed.
here. Plants were top dressed with 444, worm castings, and composted manure a week before flipping to flower. Ill give them another round of top dress f9or 
