These square plastic pots are quite sturdy. Unlike some designs with flimsy plastic these are strong and durable making them quite useful for growing orchids. The 3 1/4 inch square green pot has excellent drainage on the bottom and is the perfect size for many orchids. We like the rimless design which makes it the perfect pot to use with Rhizome Clips. The deep design of the black 4 inch pot makes it an excellent choice for orchids such as paphiopedilums, phragmipediums and miniature cymbidiums.