Even for those who consider themselves to be plant-challenged, terrariums are wonderful and impressive gifts. They are sometimes referred to as a garden under glass. No matter how big it is, a terrarium will have four layers: gravel, moss, soil, and plants.

A terrarium is a container for indoor gardening that houses plants. It is often built of glass that is either completely or partially enclosed to let light and heat in while keeping moisture in check. The Latin words terra and arium are combined to form the word terrarium. A terrarium can be used for a variety of things. They might be produced solely for aesthetic purposes, for scientific research, or for plant reproduction.

Larger houseplants can be accommodated in larger terrariums, but fast-growing species and those with large leaves should be avoided since they may obstruct the light that the smaller plants require. Look for plants that do well in low to medium light when selecting terrarium plants. Choose a variety of leaf sizes, textures, and colors for visual appeal.

Choosing the container and plants for your terrarium is half the fun. There are many types of specialized terrarium containers that you can buy, including some that cost hundreds of dollars and look like tiny Victorian greenhouses or conservatories. However, you can make a terrarium using nearly any transparent glass container with a wide opening, lid included or not like glass succulent bowl.

The majority of garden centers often have terrarium plants in miniature right next to the fairy garden supplies. Choose terrarium plants that will fit in your container and have different foliage types and heights, preferably without touching the terrarium’s sides.

The absence of drainage holes in the terrarium container will prevent water from reaching the plant roots, so you will need to create a drainage layer. Start by adding a 2-inch layer of crushed stone or gravel to the terrarium’s base. For a tall, narrow terrarium, you'll need a deeper layer of drainage stones than you would for a wide, shallow one. After that, cover the stones with an inch to a half-inch layer of activated charcoal using a large spoon or trowel to promote drainage and eliminate any odors.

Next, apply a layer of sheet moss to prevent the potting soil from mixing with the stones and charcoal. Your terrarium's moss adds to its visual appeal. Use a large spoon or small trowel to spread a thin layer of damp, sterile potting soil over the moss. Because terrarium plants don't need additional fertilizer, use potting soil without any added fertilizer. There should be at least a couple inches of potting soil added. The soil level needs to be kept low enough for the plants to fit inside the container with room to grow without touching the top of a closed terrarium.

Use a spray bottle or a small watering can with a rose attachment on its spout to water the plants so they are damp but not drenched.