Q.Why Are My Indoor Dwarf Calla Lily Blooms Turning Brown & Crisp
The original bloom color is cerise; it is a first-year plant in a 4″-5″ plastic nursery pot; it has healthy dark green, white-spotted leaves, & is in an east-facing window that receives morning sun & plenty of natural light throughout the day.
Certified GKH Gardening Expert
Unfortunately, your photos did not come through. I am unable to see the damage. This could be due to there being too much nitrogen in the potting mix, or not enough phosphorus and potassium. Usually, the nitrogen will exceed what the plant is comfortable with.
You can offset with bloom fertilizers that contain phosphorus and potassium. Just keep an eye out for nutrient burns at the leaf tips.
Another thing to consider is that they prefer, consistently, moist soils.
Make sure that you do give this a dormancy, this coming Autumn!