I purchased a mature Vanda with 3 large keikis. It looks like the plant didn't bloom regularly. The lower leaves are covered with algae and dried fertilizer.. I tried washing them off with a soft toothbrush with no success. Is there a product to remove this residue?
I think there are several points here that need clarification. First, there are lines of vanda breeding that produce large plants that may be naturally shy blooming. I doubt that the leaf deposits that you cite are responsible for the poor flowering record of this plant. More probably, it is that the plant was in a position in the grower’s greenhouse where it did not receive enough light or it is of the shyer blooming type. Second, it is possible the leaves are beyond being cleaned easily. Other methods worth a try are lemon juice and one of the new horticultural oils such as Sunspray. Too much scrubbing may damage the leaves. Personally, I look at overlarge plants of any type with some skepticism, especially if they have what appears to be a poor blooming history. For example, I would never consider the purchase of a cattleya plant with multiple unflowered growths of what appeared to be flowering size. I would not know if it would or would not flower under my conditions, but I would not waste the space on a large plant when a smaller one might perform better under less-exacting circumstances. —