Q.Vanilla orchid
I have a vanilla orchid that produces some beans or seed pods but in the past they always turn yellow and fall off within a month or so. This year I had about 50 blooms but I only managed 15 beans. All are still green and healthy looking but one is turning yellow. I am afraid they will all do this unless I do something different. Does anyone know why this happens and what can be done to prevent it? Most of the beans are about 4-5 inches long at this time. I have uploaded pictures if that will help. I have started to use fertilizer for the first time today. It is an orchid specific water soluble “orchid plus” fertilizer. These plants are outside in South Florida. I would appreciate any help you can provide.

You are on the right track.
A fertilizer schedule is key.
Here is a link with more information.
https://www.gardeningknowhow.com/ornamental/flowers/orchids/grow-vanilla-orchid.htm