I have a china doll that I purchased last summer in a greenhouse. It seemed healthy until about a month later the top leaves started turning black and now they are brown and drying out. I am wondering what the problem is. My water has a lot of calcium in it and I am wondering if this would be causing the problem. I live in south central Canada. Help please. thanks
Thanks for the photo. That clearly reveals the problem. The most common mistake in potted plant care is putting plants into pots that are too large. Yours is about 3 times larger than it should be.
Pots that are too large hold excess soil, which acts like a sponge retaining water around the roots for too long and causing root rot. The symptoms you described are classic root rot symptoms.
Unfortunately, the damage was done a while ago and the roots have been slowly rotting for a long time and the effects are just now showing. There is little you can do to get the China Doll to recover. Be mindful that the roots need to dry out. So, allow the top inch of soil to dry before adding any water and then add just enough so that the soil reaches that level of dryness again within a week or less.
I don’t recommend downsizing the pot because the roots are too weak to withstand the trauma of repotting. Fertilizer will not help and there are no instant cures or fixes for root rot. You simply have to wait patiently and hope that there are enough roots left to support the plant while it slowly produces new roots in drier soil. First the plant will have to stabilize and then slowly push out healthy new growth, if it is to recover. If you don’t see stability and new growth within a month then the plant will probably not recover.
I don’t think excess calcium is causing the immediate problem. However, over time excess calcium build-up can reach toxic levels. Therefore, I suggest you switch to filtered or distilled water.