Terrarium gardening, a century-old trend of bringing nature inside during the winter, has had a revival and terrariums would make an excellent gift for the holidays.
The invention of terrariums is attributed to English botanist Dr. Nathaniel Ward. He used a closed bottle filled with tiny ferns and grasses growing in soil in order to observe a hummingbird moth chrysalis. After watching the moth emerge, he continued to watch how the ferns and grasses continued to grow for four years, during which time he never opened the bottle to add water.
Most gardeners today are building an open system, without a lid, requiring some water but not as much as a normal houseplant. These open system ecosystems provide for ample creativity by building a mini landscape but also require minimal care.
Terrarium supplies: Open glass container, soilless media (not the stuff in the backyard, but the stuff you buy in a bag), 2-3 small succulent or tropical plants, ornamental knickknacks or trinkets.
1. Fill soil at least one quarter of the depth of the container or as deep as the root balls of the plants you have chosen.
2. Add either all succulents or all tropical — do not mix and match as each have different light, temperature and moisture needs.
3. Water with a mister or add small amounts of water at a time with a spoon. In the beginning, the roots are small and the entire media does not need to be saturated.
4. Add whimsy. Reflect your gift-recipients' interests with fun or meaningful trinkets placed among the plants
Care: Place in a well-lit window. Do not fertilize until the second year and then only about one quarter the rate for houseplants. Some plants may require pinching back to keep small. Pinch plants back to a node, where the leaf attaches to the stem, and this will cause the plant to grow wide instead of tall.
Why no rock? In the past, most terrarium gardeners believed rocks under the soil created better drainage. However, this is a horticulture myth passed from gardener to gardener. Experiments have demonstrated that water does not easily move from fine texture layers to course textured layers. This is because cohesion of water is stronger than the gravitational pull. Water is held tightly in the soil and must be completely saturated to allow water to go to the next gradient level, and by then the soil is too moist.