Today I uprooted the very sad looking kaffir lime tree and inspected the roots more thoroughly. I definitely have a case of root rot on my hands. You can see that the roots are wet and soggy, and the brown sheath on the roots rub off very easily with my fingers.
I have read that root rot can be treated with a 20% bleach solution, so that’s what I did. I made up a bucket of 20% household bleach, and sat the tree in it for a couple of minutes.
I then re-potted the lime into the same soil, but in a terracotta pot rather than the grow bag that it has been in. I then flushed the new pot and soil with the bleach solution by pouring the whole bucket over the new potted tree in soil. I now need to leave it until the soil dries out – and must not water until the top 2 inches of the soil is dry. I suspect that it may be too late for my poor little tree, but we’ll see how it goes.
I am keeping a close eye on my other trees, because I have obviously been overwatering them too. I unpotted one of my apple trees today, but the roots of that look OK. More of a concern is the reaction to the foliar feed of iron chelates that I sprayed the other day. I think that is what caused the black blemishes on the young leaves of my mandarin, and my mulberry has blemishes too, and it has dropped a bunch of the immature mulberries. Tragedy. I don’t know what I was thinking by spraying the mulberry with the iron. It was clearly only the citrus that needed it.
**Update** My Kaffir lime eventually died – I think it was just too late by the time I treated it. I’ve been treating root rot lately by using Phosphorous acid (in the form of Yates Anti-rot). It can be used as a preventative treatment too.