I grew some Og kush plants outside a few years back in 5 gallon buckets. The tallest one grew 8 feet tall (untopped). I harvested a half pound per plant, and keep in mind that og kush is notorious for low yields. I fed them daily with GH nutes that aren't even on the market anymore. I don't know what strain you're growing but most indicas will yield quite a bit more than the og does. Hopefully your doing some type of indica dominant strain because sativas shoot up like crazy. I definitley suggest you top your plants. Respect!