Chapter 1

In a closed area growing plants rapidly use up the CO₂ in the environment and replace it with oxygen. When the plants use up about one third of the CO₂. which doesn’t take very long if the plants are large or in rapid growth phase, plant growth virtually stops.

     The situation becomes most serious in areas without any internal air circulation, such as a fan. This is because a microclimate forms around the leaves. The small area directly around the leaves rapidly depletes of CO₂. Even though there may be adequate CO₂ levels a few inches from the plants, the leaves themselves are not in direct contaCt with air containing enough

CO₂.

     CO₂ replacement is necessary even in a room with good internal circulation. A closed room full of healthy growing plants can use up the CO₂ in less than an hour. A large room with small cuttings or seedlings doesn’t use up the CO₂ nearly as quickly but the CO₂ still must be replaced.