Dendrobium Speciosum with burn marks on leaves.

[DennisKennedy]

I suspect my problem may be overfeeding but I cannot rule out too much sun.

My Dendrobium Speciosum has developed burn marks on the edges of its leaves with just a couple of marks in the centre of the leaves. I note too some tip burning on my Dendrobium Kingiannum.

Is using the recommended strength of orchid food weekly a mistake. I recently read that I should treat half the recommended strength as the usable standard and increase or decrease slightly from there.

As a complete novice, I would welcome your comments.