Bell Peppers aren't producing.? I have 4 bell pepper plants in my garden, and solely one...

I have 4 bell pepper plants in my garden, and solely one of them are producing any veggies. . The others are budding and even starting to have started producing vegetables but then the buds finish up falling off. I thought i've done everything so this doesn't happen, but i guess not. Any suggestions would be amazingly helpful.
Answers:    Bell peppers will abort blossoms when they dance into "survival mode" due to stress from temperature extemes, exess water or withdrawal of it, or fertilizer problems. Did the one producing fruit start before a hot spell or cool spell began? Try to fix up a moment or two mid afternoon shade for them if it is really hot where you are. If it is still cool, below about fifty five or sixty at dark, wait for warmer weather. Peppers prefer economically drained soil compared to waterlogged. It might even pay you to do a soil test.