‘the growth accelerator’ is an experimental greenhouse that was designed and built by michael jantzen in 1986 for the missouri botanical garden in st. louis, missouri. the small mobile structure functioned as a public exhibit that explored how to grow plants more energy efficiently in cold climates. the modular construction could also be located almost anywhere since it was transported fully assembled on a truck bed. it was simply set elevated above the ground onto attached self-leveling supports.

images courtesy of michael jantzen

the structure was made of five sections: four low profile insulated glazed sections, and one taller insulated section. the four lower profile sections were designed to be just large enough to contain the plants, and the one taller section was just big enough to contain one person who attended to the needs of the plants. this was done in order to reduce the amount of heating and/or cooling energy needed to maintain the correct temperature for the plants by reducing the contained volume around them, and the one maintenance person. 

the growth accelerator was made up of four insulated glazed low profile sections, one taller glazed section and one heavily insulated section

two of the low profile glazed sections could be slid open over the top of the other two in order to ventilate the structure during the summer. in addition, shade cloth could be attached over the low profile sections, and an exhaust fan could be used for additional cooling.

the glazed section

during long winter nights, the plants that were contained on telescoping stainless steel benches could manually or automatically be pulled with a small electric gear motor into a heavily insulated chamber to protect them from the cold. these benches also contained large amounts of a special thermal mass material that absorbed solar heat during the day, and at night that heat was used to keep the plants warm inside of the glazed sections of the greenhouse, or inside of the insulated chamber.

the heavily insulated section where the plants are moved to during cold winter nights

a small computer was used to control the movement of the plants. it could decide when or if the plants should be automatically moved out of the insulated chamber and into the glazed section when the light level and temperature were correct. as an example, on a cold cloudy day with low light levels and low temperatures, the computer may decide to leave the plants in the insulated chamber, and turn on the electric grow lights that were mounted above each of the telescoping benches. those decisions were based on the use of the least amount of energy to keep the plants alive. the computer could also automatically water the plants.

the entrance into the one glazed section large enough for one person to stand and tend to the plants as they move by on stainless steel benches

a person standing in the tall glazed section of the growth accelerator could also do all of the plant care and maintenance manually. this was done as that person slowly moved the benches and plants past them and into or out of the low profile glazed sections.

inside the one taller glazed section

inside the heavily insulated chamber with backup electric grow lights and stainless steel telescoping benches

view of the plants moving out into the low profile insulated glazed sections of the structure

view of the thermo mass solar heat storage rods used to heat the greenhouse at night and during cold cloudy weather

view looking down into the low profile insulated glazed sections

view of the low profile sections open during the summer

the section was covered with a shade cloth to keep the plants cool

project info:

name: the growth accelerator from 1986

architect: michael jantzen

year: 1986

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edited by: lynne myers | designboom