Overwatered Lemon tree?
My mum has watered my lemon tree with banana water approx a week after its previous watering, I have noticed that some of the leaves have slightly began to cup and i’m worried. Could it be nitrogen toxicity underwatering or overwatering?
Certified GKH Gardening Expert
No. These need much more food than just banana water. This is likely a mix of a few issues. A lack of light, if you can't leave it outside for the winter, or if it doesn't receive 8 (6 at the least) hours of direct, unobstructed sun (windows are still a slight obstruction, and the more light the better) then it will not be enough light.
It will be happy under a 200 watt horticultural light when it is not outside.
Overwatering can cause this as well. The soil needs to dry out pretty well between waterings. It should be bone dry down to 3 inches before considering watering again.
And underfeeding. This will need a granular 3 (once at the very least) times per year, or a liquid feed every month.
This article will help with the care of lemon trees in container: https://www.gardeningknowhow.com/edible/fruits/citrus/growing-citrus-trees-indoors.htm