About

The purpose

The goal of this weblog is to encourage people to enjoy the miracles of tropical plant life without travelling. If no garden is available and daily duties like watering seem tedious, hermetospheres are the perfect choice. They are miniature, self-sustaining, tropical ecosystems, cheap and easy to realize: start a container and observe what is going on inside. Follow a few simple rules and learn with every attempt. My weblog can help you avoid mistakes and find explanations for your own observations.

The form

Why a weblog in times of YouTube and Tiktok? It doesn’t take much to create a hermetosphere, but it does take time. Hermetospheres are therefore an opportunity to slow down, some call it meditative. Things develop slowly in the container. The slower the better, as we will see. While you wait, you have time to read and get to the bottom of things. Hermetospheres are not science, and science is not required. However, my aim is to use sources of information that are as reliable as possible and to disclose them. Finally, the weblog allows me to tell stories that seem remarkable to me about the plants I use.

The history

Wardian cases are said to be the first forms of hermetospheres. They were made from wood and glass and completely transformed botanical science, as they made it possible for the first time to transport live plants across continents by ships around 1830. This led to an immense increase of knowledge about the flora of the tropical regions among European scientists. This context is nicely described and illustrated in an article on Kew. But the consequences were not limited to the world of academia. The Wardian case was also a major economic game changer. It did not only help bringing the Brazilian rubber boom to an end but also the British Empire becoming independent of tea deliveries from China. The Australian curator and historian Luke Keogh published an excellent book about all this in 2020.

The traditions

Bottle garden, nano terrarium, wabi kusa and biOrb represent different forms and traditions of small glass containers where a selection of plants is grown. The special thing about hermetospheres (also called closed terrariums or eternal terrariums) is that they are closed systems* and need hardly any maintenance.

My way

How I got the bug, I described in one of my first entries.

As often, there is no right and wrong regarding hermetospheres. Over time, I established my own way of exploring this wonderful world. Here, you find the basic principles that worked best for me so far. I suppose these might change with more and more experience.

Every new container is an experiment. My ambition is to find set-ups where the initial selection of plants stays in balance for as long as possible, and every plant is able to develop second and third generations with as few interventions as possible.

My standard glass container is a 5-liter household preserving jar with swing stopper and rubber gasket seal.
The basis of my substrate is lava. It is close to chemically inert, i.e. it releases neither salts nor acidic or alkaline eluents. Every grit size between sand (>0.63 mm) and pebbles (as long as they fit into the opening of the jar) applies.
Because lava releases virtually no nutrients, and because I plant my jars sparingly, I add a limited amount of nutrients to my substrate: 1 part of an organic fertilizer (N:K₂O:P₂O₅ = 1.2:1.2:0.9) is mixed with 5 parts moistened (drained) coco peat, and this mixture is then mixed with 20 parts moistened (drained) lava. The coco peat helps retain moisture and nutrients in the substrate.
Following Ulf Soltau’s advice, I start the jars with the amout of moisture that just not produces stagnant water at the bottom of the container. In the event of the occurrence of mold, I slightly reduce the water content by opening the jar for a while and letting the condensed water at the inside of the glass pane evaporate. The water I use is demineralised or distilled (as my tap water contains a lot of calcium carbonate).
Where the glasses are placed, they do not receive direct sunlight and most likely too little natural light. Therefore, they are additionally illuminated by two LED lights in a 12h rhythm; light intensity varies between 10 and 100 µmol m^-2 s^-1 depending on the time of day and the position on the shelf; direct sunlight is avoided at all time.
I only combine plants of the same geographic region. For information on the native distribution of a plant species, I rely on the database of the Royal Botanical Gardens Kew. Information provided by dalers is often incomplete or incorrect. This is not only the case for geographical data but also for genus and/or species indications. Before buying a plant, I try to collect as much evidence as possible to be sure it really is the plant I need.
Containers are only opened for minor adaptions and window-cleaning. On this occasion, I usually take pictures to document the development.
I strive for slow growth of my plants. By using mainly small and slowly growing species, I reduce the risk of one species overgrowing the entire container while others get eliminated.
I only use plants that can deal with the specific conditions in my indoor containers: Permanantly high humidity of up to 100%; small differences between day and night temperatures; around 20°C year-round. So, almost all my plants are native to the humid, tropical low-land regions of Central and South America, Africa or South-East Asia.
As far as I know, all plant species I use are cultivated natural forms. Because of a high demand from collectors, a lot of tropical plants are endangered in their natural habitats. Under all circumstances, I try to avoid buying or trading plants that were harvested in nature.

About me

Drawing by beaW

Almost thirty years after my degree in plant physiology and microbiology, the newly discovered passion for hermetospheres led me back to my personal roots.

Herbert Winistoerfer

* Strictly speaking, the hermetosphere is not a closed system either. Besides occasional opening, where gas exchange happens, the system is only closed in terms of materials. In terms of energy, light (radiation energy) enters the system and warmth (thermal energy) leaves the system.