Black Prince echeveria needs good light and roots that dry between waterings. A dark leaf color does not justify exposing a shaded plant to sudden harsh sun.
Dark leaves still need light
Black Prince echeveria is grown for a compact, dark rosette. Provide a bright position and acclimate it gradually to stronger exposure. Compare the newest growth rather than judging health only by how black the older leaves appear.
Use drainage rather than a watering calendar
Choose an open succulent mix and a pot with an outlet. Water when the root zone has dried appropriately, letting surplus escape. Cool or quiet growth generally needs less intervention than warm active growth.
Keep the base visible
Remove detached, deteriorating leaves from around the stem. Leave firm, healthy foliage intact and avoid burying the rosette beneath decorative grit or a wet top layer.
Do not confuse symptoms
One lower leaf drying can be normal. Widespread softness, a weak base or a pot staying wet warrants closer inspection. More fertilizer will not repair damaged roots, and severe drought or cold is not a sensible way to force dark color. Protect the plant from freezing.
