If your hot pepper plants get excessive nitrogen in the soil, this can lead to yellowing of the leaves where the lower leaves on the plant turn yellow while the veins are dark green or brown. If this continues, eventually the leaf tips and edges will turn brown and become brittle. If this sounds like what is happening to your hot pepper plant, the solution is to over-water the plant for the next several waterings. This will flush the extra nitrogen out and if the roots have not been affected, the hot pepper plant should recover.