Terrariums can use various different containers. Here, I used a large glass jar. I centered it around one plant, Homalomena Insignis. This plant requires high humidity, so I kept the lid on tightly. To avoid mold and promote plant growth help, terrariums often have multiple layers for drainage of nutrients and aeration. I also added moss and other plants that should compete with mold for nutrients and choke it out. However, the mold still grew so I had to dose the mold with hydrogen peroxide.