What is the term for a low tech version of a greenhouse used to produce vegetables?

The term for a low-tech version of a greenhouse used to produce vegetables is a cold frame. A cold frame is essentially a bottomless box that is usually made of wood and covered with a transparent material like glass or plastic. It captures heat from sunlight, creating a warmer microclimate for plants, extending the growing season particularly in cooler climates.

High tunnels are often used in more commercial applications where ventilation, heating, and other technological advancements may be involved. They allow gardeners to extend the growing season by providing shelter from harsh weather while still being somewhat open to the environment. However, they are generally larger and equipped for more intensive agricultural practices than a cold frame.

The choice of a greenhouse typically implies a more sophisticated structure with controlled environments, while a grow tent is used more commonly for indoor gardening and often involves artificial lighting and may not adequately represent the concept of a low-tech installation for vegetable production. Thus, the correct term to describe a low-tech method for growing vegetables is cold frame.