Hi! Can anyone kindly check my lemon tree? It's with me for 6 months already. It was good until recently month. The leaves start to curl and fruits is getting soft on branches. I've placed the lemon tree at the spot with longest sunlight in my house. It didn't happen before. My location is in Singapore. Thank you!!
Welcome to the Forums. The tree may be suffering from dehydration. If possible, ease the entire rootball out of the container and have a look at the roots and the medium it's planted in. If the roots are firm and the medium is dry then the problem is from a lack of water. If the roots are mushy and the medium is wet then the problem is from overwatering. As an aside, the speckling of the leaves suggests an infestation of spider mites, now or in the past. Also the pale leave suggest insufficient application of fertilizer.
Post a photo of your container and substrate too. The container could be too small fot the tree and you may have to up pot ASAP. The potting mix may be peat based substrate, that has poor ability to provide the tree with nutrients - you should provide everything in right doses at right intervals, and be careful not to wash out most of added fertilizers with watering. With mineral soil it's much easier to maintain sufficient nutrient levels. I'm using just a sandy soil as my growing medium for my citruses, and I don't have to deal with fertilizing issues at all.