well if the mix is organic it could contain organic ferts. like worm castings. if it doesnt say time release then it isnt. the organic on the bag makes me think its ok. when you feed in soil and using worm casting or other composts- the nutrient level drops when you water. more and more the soil becomes depleated and after a month its unlikely there is much nutrition left just in the soil. id say the plant has been using the nutes in the water by now and the plant looks fine like its a lil hungry by having one main leaf yellowing off on the bottom (normal) and others starting to yellow a little. notice the leaf tips are not burned on any leaves, that tells me that the plant is fine and might need a ph ajusting since he prolly didnt use dolomite lime as a buffer...
I would say that you need to chek the ph and make it right then maybe a more balanced diet containing micronutes. try dosing her with a compost tea and see how she does after she dries outgood, use PHed water when feeding and check ph from runoff. id say could be the start of a ph issue if anything.