Grow Robust Hedgehog Cacti in the World’s smallest terrarium! Each high-quality globe is hand made and has a flat surface on the bottom to make sure it never rolls. Cacti are easy to sprout and grow and will germinate in the Tiny Terrarium in about a week and thrive for years with minimal water! The Cacti will naturally conform to the container and stay small while growing in it. However, they can grow to full size if they are transplanted into progressively larger containers.