I have two S. purpurea growing in separate pots, both placed in a large plastic container (for humidity) with no top cover (for air circulation) growing outside in peat/sand mixture.
I keep the soil wet and the plants are in direct sunlight 10 hours/day. The pitchers are some what green with lots of red veins. For the past couple months. I have noticed that new pitchers are smaller than previous, but remaining as red. I use reverse osmosis water from the water softening unit under my sink (which removes the softening salt).
My unknown Nep hybrid in a sphagnum moss terrarium inside the house is doing the same, new pitcher are smaller the previous one.
Is this normal or am I doing something wrong