Overwatered Bonsai
They don t know that watering too much is more damaging than watering too little.
Overwatered bonsai. In the case of indoor bonsai brown black tips to the leaves is usually indicative of over watering. In principle over watering is a slow deterioration where the bonsai is over watered for many weeks the roots begin to rot and then become inefficient at taking up water you then see symptoms which look similar to the bonsai drying out. Over watering your bonsai if you are accidentally over watering your bonsai the leaves are going to turn yellow brown droopy and very soft. Minor over watering is often characterised but soft black tips of the leaves.
Frequently this is also associated with the bonsai becoming loser or wobbly within the pot. Overwatering is the biggest reason why most of the container plants die. I am still not convinced that rain and over watering is the problem. So surplus water would leave after rain.
This is a process that takes a long time to achieve the odd period of over watering really isn t going to effect the tree in too much of a negative way. Your pot seems to be a real one so it should have a drainage hole. Beginner plant growers often do this mistake they keep watering their plants out of love until they summon the death for them. Your bonsai has been hit by frost or become too cold.
Dry and crispy leaves. Your bonsai is suffering from over watering. I don t know your climate but 60f is too low for a tropical bonsai.