Coco coir is a natural fiber made from coconut husks that is commonly used as a soil amendment in gardening. It is known for its water retention capabilities and ability to improve soil structure. Perlite, on the other hand, is a lightweight volcanic glass that is often used to improve soil drainage. While both can be beneficial in different ways depending on the needs of the plant, coco coir is generally considered a more versatile and sustainable option due to its ability to retain water and provide nutrients to plants over time.