You really prefer the 3gal grow bags to 5gal buckets? Do you notice any difference in yield?
What's your mix?
What nute line?
A friend of mine turned me onto the 3gal containers a few crops ago. Prior to that I used 5gal containers and was quite satisfied with them. I did a side-by-side comparison and here's how it went down:
I had a stable Sweet Tooth mother plant that I had been cloning off of for about a year. For my experiment, I took two nearly identical clones and rooted them in Jiffy Pots (peat pellets that expand into little pots when you soak them in water). After taking root and growing under florescent tubes on a 24/0 schedule for two weeks, I transplanted one of them into a 5gal container, and the other into a 3gal container. On an 18/6 lighting schedule, they were fed and watered exactly the same amounts at exactly the same time for a period of four weeks. At the end of the four weeks, the plant in the 5gal container was exactly 3" taller than the plant in the 3gal container. It also had a lateral span approximately 2" wider than the plant in the 3gal container. I cut the light back to 12/12 and began the flowering phase which continued for exactly 8 weeks (56 days). As with the vegetative phase, the nutrient and water amounts and schedule remained identical for both plants for the duration. The plant in the 5gal container grew a little faster than the one in the 3gal container for the first 3 weeks. But after that, the 3gal plant caught up and they remained nearly identical in appearance all the way to the finish line. My final measurements revealed the 5gal plant to be 2 1/2" taller and 3 1/2" wider than the 3gal plant. I then plucked all the big fan leaves from both plants and, keeping each plant whole, hung them upside down to dry. After spending one week in my dry room, both plants were fulled trimmed and manicured. The buds were then cured for a period of two weeks using the paper & plastic bag method. After the two week cure, I weighed the finished buds of each plant separately. The 5gal plant produced 58.4g and the 3gal plant produced 51.5g, a difference of 6.9g (<1/4oz.)
Given that the 5gal plant required 67% more soil and nutrients than the 3gal plant, I determined that the additional 6.9g of finished bud did not justify the extra cost of maintaining the larger container. Since then, I've been a believer of the 3gal container. I prefer using grow-bags over regular buckets because they are ultra lightweight and ridiculously cheap (they only cost $0.15/each).
As my grow medium, I use FoxFarms Ocean Forest straight out of the bag with nothing else added. I know a lot of people who use Ocean Forest like supplementing it with Perlite or Light Warrior, but I've never had any problems with it as-is and have not found it to be necessary. As for nutrients, I primarily stick with the FoxFarms product line. For my vegetative phase, I use GrowBig and BigBloom supplemented with SuperThrive and Hygrozyme. For my flowering phase, I use TigerBloom and BigBloom supplemented with Hygrozyme, along with Open Sesame, Beastie Bloomz, and Cha Ching. I do a flush with RO water supplemented with Clearex one week before I begin the 12/12 light cycle, and once again 2 weeks prior to harvest.