The lower leaves look pretty big, so I'm guessing that it's the leaf weight that is pulling the branch downward. Not to worry. However, you might have another problem with the plant height. The farther light is from a plant, the more the plant will stretch so you want to keep light close to the top of the plant. To promote the plant's bushiness, getting it to grow lower and out more, you might consider cutting off the top of the plant. It will still grow upwards, but out as well. Let the soil dry out some before watering again. I'm not sure that Bioroot is going to be enough NPK nutes for a growing plant. It looks good so far, but if you see yellowing of the lower leaves, you'll have a nitrogen deficiency and will have to add some fert kicker. It would be interesting to see what happens here, to see if Bioroot is not just a supplement, but enough NPK to grow an entire plant through its lifespan. Just stick with the bioroot and see how things go. You really need to let the soil dry out however, like maybe go a week without watering, because that's how oxygen gets to the roots - through dry soil. Roots need oxygen and too much water pushes air out of the soil. Nice plant so far. Keep us posted on your progress and what changes you make, if any.