The Greenhouse Helmet: A Patent to Grow Plants on Your Own Head

In 1986, the USPTO granted a patent for a clear domed helmet, worn over the head, containing live plants — so the wearer could breathe air freshened by their own personal, portable garden. It is exactly as wonderful and impractical as it sounds.

By Marcus Feld
The Greenhouse Helmet: A Patent to Grow Plants on Your Own Head (patent US4605000)

US4605000 was filed on January 4, 1985, and granted on August 12, 1986, to Waldemar Anguita. The title is "Greenhouse Helmet." The invention is a transparent domed helmet, worn completely over the head like a diving bell or a space helmet, with small potted plants on shelves inside and air filters in the front and back. The stated purpose is to let the wearer breathe the oxygen the plants give off. The patent also provides for hearing and speaking devices, so the wearer can hold a conversation from inside the dome.

The reasoning is drawn straight from grade-school biology. Plants take in carbon dioxide and release oxygen through photosynthesis. A person, breathing inside the helmet, exhales carbon dioxide, which the plants consume; the plants in turn release oxygen, which the person breathes. In principle, the wearer and the plants trade gases back and forth, and the wearer enjoys a supply of plant-freshened air wherever they go.

The trouble with the idea

The greenhouse helmet is a masterpiece of the sincere-but-hopeless patent, because the biology it invokes is real and the execution is preposterous. A few small potted plants do not produce anywhere near enough oxygen to sustain an adult human's breathing — you would need something on the order of hundreds of plants, and bright light, to keep pace with a single person's respiration. Whatever fresh air reaches the wearer comes in through the filters, not from the plants, which make no meaningful difference. The plants, for their part, would not do well in the warm, humid, low-light environment of a helmet, and would need soil, water, and drainage, all balanced on the wearer's head.

There is also the matter of simply walking around with a dome full of plants on your head, which the patent's drawings depict with total seriousness.

Why we love it

The greenhouse helmet endures on "strangest patents" lists because it is so purely, optimistically absurd. It is not cynical. It is not a trivial method patent dressed up in legalese. It is a genuine, buildable, carefully illustrated device built on a real scientific principle, aimed at a lovely idea — carrying your own little garden with you, breathing clean green air in a polluted world — that collapses the instant it meets the actual numbers of human respiration.

It belongs to the same warm family as the other sincere-whimsy patents in this archive: inventions that the world did not need, that were never going to work, and that make you like their inventors more, not less, for having tried. Somewhere there is a formal United States patent for wearing a terrarium as a hat, and the world is slightly better for it.

See the original

The full text and figures of US4605000 are on Google Patents.

Original patent drawing for "Greenhouse helmet", U.S. Patent 4,605,000 (1986)
Sheet 1 of 1 of the drawings for U.S. Patent 4,605,000, Greenhouse helmet, issued August 12, 1986. Public domain. Read the full patent on Google Patents →

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