Ferns not doing at all well in metal trough - why?
Hi, I am trying to work out why the ferns in the metal trough shown are doing so badly. The bracken type one on the left in the trough is much the same age, and used to be almost the same size, as the one in the pot. This is the third year in the trough, and it and the other fern at the far end have both declined steadily since they went in - unlike all my other ferns which are magnificent. All are about fifteen years old now. I don't think it is heat, which I know can be a problem for metal containers, as this is a very shady corner only getting sun first thing in the morning, and I water conscientiously - in fact it got waterlogged last year (weight of soil and water squashing the drainage holes I guess) and we had to make holes along the front to drain it. Does metal affect pH or something like that? Thanks for any insights!