GREENHOUSE CONTROL SYSTEMS - CO2 ENRICHMENT

Importance: The rate of photosynthesis is dependent upon the availability of carbon dioxide.
Carbon dioxide enrichment is most important during the winter months in the morning. The sun has risen and photosynthesis has begun. The plants can reduce the levels of carbon dioxide from the ambient level of about 330 ppm (higher in cities due to industry and vehicles) to around 220 ppm. Lowered carbon dioxide levels will reduce growth and can cause flower and
fruit drop reducing overall yields.
*Ways of controlling carbon dioxide levels in the greenhouse:

1. Ventilating (bringing air in from the outside) may provide sufficient carbon dioxide during the Spring, Summer and Fall months.
2. Ventilating during the Winter months, or anytime in cold climates, will, however, result in cold outside air being brought into the greenhouse. Heating will then be needed to maintain the proper temperature which may become uneconomical. Therefore, carbon dioxide generation is a typical and effective way to increase levels in the greenhouse during the Winter or in cold climates.
   
3. Carbon dioxide generators can burn various types of fuel including natural gas (most economical)or propane. Carbon dioxide levels above 800 ppm, even as high as 1200 ppm, have been shown to be beneficial to plant growth.