Alrighty. Read through the whole thing again and I hope you don't mind some suggestions. Please take this in the light of "this guy is trying to help improve my grow" and not a "this guy's being a dick insulting my grow".
First thing to do is fix that light mounting. Jammed in there at that awkward angle, it is eating up valuable plant space. You could prolly fit 3 or 4 of those party cups in there. Even if you are just sticking with one plant, you are still sacrificing way too much growing area to that light. Can you bring that plug up any higher? Run a little bit of extra cord up that inside wall and use some duct tape? Maybe go all out professional style and cut a hole and really custom mount it? Perhaps look into the flat pl-l bulbs (I think that's what they're called)?
Second, consider a ScrOG or LSTing your plant. Use a wide but shallow container such as a pencil box or small rubbermaid or tupperware something that fills the bottoms of your box. To LST, you'd tie the plant down around the edges of the pot, for ScrOG you'd mount a screen, like some chicken wire or a cookie cooling rack, and train the plant to grow under it. Plenty of great tutorials on training methods on this and other sites. With such a small space, maximizing usage of that space is vital. This goes hand in hand with moving your light bulb.
Third, consider your watering technique. In such a small container, it's easy to become "root bound", but, really, root bound is just a state of mind. If you supply your plant with optimum conditions, it will thrive. When you water with small containers, what you want to do is put the container into a larger container, like a coffee can or bucket, and then fill with water/nutes until the dirt/root mass is completely submerged. Leave it underwater until all bubbles stop rising to the surface. Now remove and let drain thouroughly. This will pull oxygen down to the roots and give your roots access to all the water and nutrients it can use. Do not water again until your plant is just starting to droop from needing water. In very small containers and under warmer temps, you may need to water every day...it may be every 3 days. Learn to read your plants.
To use bananas, place the peel in a blender with a cup or so of water and blend til smooth. Mix with your gallon of water and let steep for an hour, then strain before watering your plants with it. It is really only good for the day you make it, so only make what you need. Use the molesass at about 1 tsp per gallon of water, and, again, it can spoil pretty quickly, so only make what you need. You can combine the two together.
I hope this helps, and I'll do my best to answer any questions you have.
*edit*
Going to give you this
link and this
link and hope they give some inspiration.
looking good on your grow mate, +rep
