Calathea Grey Star

Ctenanthe (pronounced te-NANTH-ee) setosa 'Grey Star' is an evergreen, clump-forming, herbaceous perennial plant. Although it can produce white blooms when grown indoors, 'Grey Star' rarely flowers—this plant is all about the dramatic foliage. It can be grown in the garden in zones 10 to 11, but in most regions, Ctananthe plants are grown as houseplants, and with enough shade, moisture, and warm temperatures, they easily thrive.
Light
Too much direct sunlight can result in fading colors on the leaves of Ctenanthe setosa 'Grey Star'. Provide the plant with a sheltered spot that gets bright but indirect sunlight to ensure the most dramatic foliage display. Too much shade can also result in diminished variegation and leggy growth. Place the plant in bright, in-direct light for best results.
Soil
This houseplant requires a well-drained potting mix with good aeration to ensure the right combination of drainage and moisture retention. Add perlite to mix for good drainage. Use a mix with good nutrients, as this is important for a plant that has such large and colorful foliage.
Water
Water your plant with the right amount and temperature of water. During summer, keep the soil moist but not waterlogged to avoid root rot and leaf fungal problems.
Typically, twice-weekly watering is best, but you should test the soil to make sure it is not already feeling soggy. When the top 1 to 2 inches of soil is dry, that's when it's time to water the plant. Water it slowly and only until the water begins to drain from the pot. Remove the excess water so the plant is not sitting in any water.