Following johmerr suggestion to water with Foliage Pro augmented with vinegar I have seen some improvement in my lemon tree but no lemons (it has flowered tho). Recently I had a new flush of leaves and some yellowing of leaves but I think that is normal as the seasons change.

Going forward, when do I stop feeding with FP, or do I stop? I assume I continue to water with 1 T vinegar/gal. In the spring I will add Osmacote to my pot when I bring in outdoors again. I hope one day to actually get lemons.