Answer: It sounds like the soil lis staying too wet, especially since you have a layer of heavy soil underneath that may not allow the top layer to drain adequately. Peppers don't like wet soil, and, as you saw last year, they can withstand soil on the dry side as long as they don't dry out too much. Peppers are also very sensitive to cool weather (more so than tomatoes) and do not do well if exposed to too much wind.
Here are a few suggestions: You might try using a foliar fertilizer such as a fish emulsion/kelp mix to give them a boost. You could also try digging some of them up and planting them in containers. This way, you can keep an eye on drainage, and the containers absorb heat, warming the soil, which peppers seem to like. Just don't let them dry out! You could also try laying a black plastic or a special IRT mulch down, which can help maximize the warmth the plants love.
Pepper flowers are known to drop when night time temps get too low--and the low 50s is pretty low for this heat-loving plant. You can try covering the crop with a fabric row cover. This will capture heat during the day and maintain warmth around the plants during the night. Hope this helps!
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