I'm afraid that plant is starting to die. The bucket is pretty small for a plant that size but that isn't the problem. Get some Dynagrow 7-9-5 at a hydro shop. It can be used for both soil and hydro grows and has pretty much all the nutes you need. Put one half teaspoon in a gallon of water, give that, then let the soil dry out before you water again. If it's hot in your area, it won't take long for the soil to dry. You have severe magnesium deficiency and low nitrogen in your soil, probably among other things. Dynagrow will fix most of your nutritional problems.