The technology Ward used was readily available, but the concept of a sealed terrarium was groundbreaking. While glasshouses were relatively common among professionals, the theory hadn’t been applied on a smaller scale. Greenhouses use solar radiation to heat the space, creating a warmer environment that is favorable to tropical plants. Both systems use similar technology and structure, but greenhouses usually require additional watering and human interference.

The Wardian case, by contrast, is an almost completely sealed environment that uses the process of condensation and evaporation to maintain humidity. The system was self-regulating, and it did not often require additional watering. London’s 1851 Great Exhibition included a Wardian case with a plant that allegedly had not been watered in 18 years.

Prevailing thought held that plants needed constant exposure to fresh air to grow during sea voyages. By sealing the box closed and using glazed windows, Ward broke with convention. This was beneficial on a sea voyage where freshwater supplies could be limited, and sailors often didn’t understand how to take care of plants. Ward’s experiment quickly earned the support of George Loddiges, owner of the Loddiges and Sons Nursery in Hackney. The foremost nursery in London, Loddiges traded plants with clients worldwide. He saw the potential in Ward’s case: A sealed means of plant transport would present valuable commercial potential.

By 1833, the pair was ready to send two Wardian cases of plants to Australia. The ship returned a year later with a load of thriving Australian specimens. “These plants were placed upon deck, and were not once watered during the whole voyage, yet on their arrival at the docks they were in the most healthy and vigorous condition,” Ward wrote.

Before the Wardian case, plant transit was principally conducted by shipping seeds. To succeed, packers needed a strong understanding of horticulture to harvest the seeds at the correct time and properly dry them. According to the historian Stuart McCook, two techniques were common for transport: covering seeds in beeswax and storing them in honey, or placing them in sealed, silk-lined tin canisters. These methods yielded low success due to pests, seed rot, and desiccation.

Previous attempts to transport germinated plants were stymied by the insistence that fresh air was necessary. Plants often died on these journeys due to vermin, extreme temperature changes, saltwater spray, and sun exposure. In 1770, the naturalist John Ellis recommended using a small box with wire coverings to prevent rats from climbing inside, and as late as 1819 the botanist John Livingstone recommended sending a gardener with every shipment. The ships attempting to transport these doomed goods were nicknamed “floating gardens”; the high failure rate forced the crews to carry many extra plants as backup.