What Are Decorative Plant Terrariums?

• Open terrariums can be used to showcase exotic plants Ryan McVay/Lifesize/Getty Images

  When Dr. N.B. Ward, a 19th-century London physician, discovered grass and a fern growing in a closed bottle, the first terrarium was born. Ward's studies on growth of plants in closed conditions launched an interest in terrariums that last to this day among plant enthusiasts. The different styles of terrariums -- closed, open, and dish garden -- all have one thing in common: little maintenance and decorative interest.

Closed Terrariums

• The closed terrarium is the variety that began the terrarium craze, and is the one most familiar to the general public. In a closed terrarium, plants are grown in a sealed clear glass or plastic container that is only opened two or three times a year in order to add more water.

  Closed terrariums are created by adding a layer of gravel to the bottom of the container, followed by a layer of soil, in which the plants grow. Closed terrariums work best with plants that like warm, moist conditions, such as tropical plants. Ferns, croton, philodendron and gloxinia are examples of plants that grow well in closed terrariums.

Open Terrariums

• In an open terrarium, a tall, clear glass or plastic container with an opening is used. Glass vases with tall sides, large glass bowls or even aquariums are containers that are often used to create open terrariums. Unlike closed terrariums, open terrariums must be watered regularly, especially if plants that need high humidity, such as tropical species, are used.

  Closed terrariums are constructed like open terrariums, with a layer of gravel, followed by a layer of soil in which the plants are rooted. Nearly any houseplant -- aside from cacti, succulents, and other desert plants -- can be grown in an open terrarium, where the culture is less humid than a hothouse.

Dish Gardens

• If you love cacti, succulents and other desert type plants, a dish garden is the terrarium for you. Dish gardens, which use wide, shallow, open containers to house a variety of plants, are perfect for cacti and succulents, which come in dwarf varieties that allow a number to be planted in a small space.

  Dish gardens can be used for any small plant, regardless of humidity and water need. African violets are an example of a small, low-growing plant that can be used in a dish garden. Like other terrariums, dish gardens are constructed by adding a layer of gravel to a container, then soil and plants.