These cuties are made of concrete but we recommend they spend the winter indoors. Most all plants grow better in a container with a drainage hole - these have one. They also have a plastic plug so the planter can hold moisture if you wish. You could use the critter planter for a teeny, unique flower centerpiece. It would be an adorbs gift for a shut-in or for a child’s bedroom windowsill. If you nestle a small potted plant in the planter opening, either remove the plug or make sure there’s no puddle of water in the bottom after watering. Soggy bottoms = rotten roots!