Check your soil ph...? What bell peppers like: -Warm temperature and soil. Studies have shown increasing the soil temperature bell peppers are planted in will increase their yield and the overall health of the plant. In areas where temperatures are not already high outdoor bell peppers may need in ground heater to produce large fruit. -High humidity. Bell peppers love humidity, hot and dry can not only affect pepper size but may even kill the plant. You can increase humidity by misting, planting humidity increasing companion plants and ground covers to help the soil stay moist. -Well drained soil. While bell peppers do enjoy humidity they don't enjoy being over watered. They are also prone to root rot. Be sure your soil drains well (clay is not recommended) or if you are container gardening provide ample drainage. -Space to stretch. Peppers will grow in close quarters with other plants, but overcrowding can affect pepper size. Make sure any companion plants don't prevent sunlight from your peppers and that there is enough room for roots. Peppers also don't like to be alone as they can be fragile to the elements. Around a foot between each plant is considered ideal to block wind but give each plant its space. -Slightly Alkaline pH. pH can have a dramatic affect on fruit growth. Bell peppers dislike acidic soil preferring a pH of around 6-7. How to maintain bell pepper plants for optimal health: -Prevent Pests. Any type of pest or disease in plants will affect health and in turn affect pepper size. Check your plants regularly for infections. As bell peppers are food plants organic pest control is recommended. Several companion plants will deter most pests such as marigolds. -Pinch early flowers. Sometimes bell peppers will attempt to make peppers before maturity. If you catch your bell peppers trying to jump the gun, pinch the flowers before fruitation and your later harvests will be healthier.