Your dendrobium looks nice and green. You may want to increase the sunlight alot. I had been growing my dens on my porch and got no blooms. I change their location last fall, to a side of my home that gets almost full sun. They only get shade when the sun is directly overhead. They burned at first, but then the new growths adapted and I got tons of flowers. I have to say, I am also being more careful about how often I fertilize as well. I am using more fertilizer...and varied kinds. With the dens, vandas and other heavy feeders; I use a fish emulsion every couple months as well. I've been known to actually add tomotoe plant fertilizer, rose bush fertilizers, african violet food...dish detergent, egg shells...whatever strikes my fancy, to make sure my plants get a varied "feeding". The only thing that is a constant...keep it weak. You will see burns on the tips of your oncidiums if they get too much fertilizer...some plants will die from too much. I hear some even use the water from their fish aquariums (not salt water tanks). But having said all that about fertilizers...really, sun is the main thing for blooms.