An early Victorian botanist called Ward discovered that some plants grow happily in closed glass cases like tanks. Bottle gardens thrive on the same principle. Within such a Wardian case, the air is still and draught-free, un-contaminated by dust or other pollution, and as consistently dry or damp as required. The temperature does not fluctuate much and water is not lost through evaporation. Therefore many delicate plants, which would be hard to keep in the open, prosper inside with little, if any, attention. Such cases can be small or large, kept indoors in a warm place or outdoors in the cool – and contain plants chosen accordingly.
As there are noholes in such a , a layer of charcoal at the bottom is needed and then a layer of peat. The (John Innes No. 2) looks best if not spread level but with some mounds, and a few stones or small rocks added. The plants should be grouped, with taller ones at the back and the smallest in front, but with space for growth between them. Moss can be added to cover the bare patches of compost.
The case should be kept in a light but not sunny. Some ferns and ivies prefer shade. No should be needed, and no fertilizer. You will see water from the plants condensing occasionally on the glass and running back into the compost. A glazier could provide you with glass with which to make your own Wardian case on a wooden frame, with a glass lid, or you could convert an aquarium tank. Garden shops now sell Perspex and polythene versions, intended as propagators for . If you can pick up from a junk shop an old Victorian glass dome (once used for covering stuffed birds, or over clocks) and find a bowl of matching size to put it on, you could grow one or two taller plants in this.
In addition, you could devote one case entirely to, mixing sand with the compost. Another would do for ferns, ivies and other plants collected from a woodland. You might keep one case for fruit- plants, another for or small flowering indoor plants. Do not mix plants that have different cultural needs. In the case of , you will have to water very occasionally, ventilate if there is too much condensation, and remove dead .