Wardian cases are what got me first interested in terrariums. They are originally Victorian miniature greenhouses, built of glass and metal or wood.
This type of terrarium is a great solution for those who don’t have a green thumb: once established, no further care is needed. You don’t need to water the plants or fertilize them. Just find a good spot and enjoy the view.
Bottled and jar gardens are just a simplified version of the ornate Victorian Wardian case.
The principle was discovered by Dr. Nathaniel Bagshaw Ward (1791–1868), a London physician with a keen interest in biology and especially ferns.
In one of the closed glass jars in which he kept moth cocoons, plants germinated and managed to grow for some time. He then had cases built in which he experimented with his fern collection.
These miniature greenhouses, named Wardian case in his honor, quickly became a success in Victorian society: they allowed people to grow delicate plants like ferns and orchids in a controlled and protective environment.
Soon every household had to have a Wardian case to boast their collection of exotic plants.
And, in and era of exploration and discovery, they allowed transport of delicate plants during long maritime travels by ship.
How does it work?
A Wardian case is a sealed box, no air goes in or out. The plants are grown in a layer of soil, the plant evaporates water, the water condenses and flows back into the soil.
Sealed is probably too strong a word: you need to be able to open the case to adjust the water in the early stages. There should be enough water to have condensation on the glass wall when temperatures drops, but not so much that the soil is wet and condensation is too heavy.
But once the water problem is settled, your plants will grow for months or even years in your Wardian case without any further care.
How to install a Wardian case:
- install a drainage layer: gravel, pebbles, expanded clay pellets… at about 1/3 of the height of the bottom tray
- put a layer of active charcoal on top: this will filter the water of impurities and absorb toxic chemical products. The charcoal sold for aquariums is the one to use.
- put a layer of soil on top (2-5 cm)
- install the plants
- water with a vaporizer
- close the Wardian case
You will need to observe your Wardian case for a few days: there should be slight condensation on the glass walls in the morning, after temperature has dropped during the night.
If you don’t see condensation in the morning, vaporize some more water and observe again.
If there is too much condensation, leave the case open for a few hours to allow the excess water to evaporate.
Plants suitable for Wardian cases:
Since your Wardian case has certain dimensions, they are not suitable for plants that outgrow to Wardian case.
So no big plants and no fast growers that will soon suffer by lack of nutrients in the soil.
Wardian cases are perfect for plants with limited size and slow growth: ferns and orchids are the most likely plants to grow in a Wardian case, as well as some smaller plants like Bromeliads, Helxine, Peperomia…
The light depends on the type of plant but a Wardian case should never sit in direct sunlight for too long as this will overheat it.
The best place is a light place with occasional direct sunlight.
The nutrients available in the fresh soil with which you plant the Wardian case are sufficient for slow growing plants.