Chapter 4

Greenhouse Environmental Control Systems

(draft book excerpts)

The goal of all environmental control systems for greenhouses is to enhance the growth of the plant, and provide a mature crop in timely fashion, with desirable quality as demanded by the market of the producer. The pressures of labor availability and costs, energy costs, and market demands increasingly make efficiency and automation key components for success and profitability. Environment control technology affects all of these critical areas, and many others, so understanding controls and implementing their use is more important than ever. Precise control of the greenhouse environment is critical in achieving the best and most efficient growing environment and efficiency. Temperature and relative humidity (and/or vapor pressure deficit) need be monitored in every greenhouse. Carbon dioxide levels should be monitored since it is an important greenhouse climate variable, which enhances the growth of the plants. Light levels should be checked at least periodically in the greenhouse to make sure covering materials are performing adequately, but ideally light levels need to be checked on a regular basis in order to know the optimal temperature regime for the crop. The electrical conductivity and pH of both the feed and drain solutions should be monitored in every hydroponic system.

Click on the following topics for more information on greenhouse environmental control systems.

Topics Within This Chapter:

  • Types of Environmental Control Equipment
  • Thermostats and Timers
  • Stage Controllers
  • Computer Zone Controllers
  • Integrated Computer Control (ICC)
  • Greenhouse Sensors
  • Sensor Principles
  • Temperature
  • Air Temperature
  • Substrate Temperature
  • Plant Temperature
  • Humidity
  • Light
  • Carbon Dioxide
  • Wind Speed and Direction
  • Precipitation
  • Irrigation Scheduling with Substrate Sensors
  • Principles of Substrate Sensors
  • Tensiometers
  • Electrical Resistance Blocks
  • Dielectric Sensors
  • Greenhouse Wireless Sensor Network
  • Base Station
  • Sensor Nodes
  • User Interface
  • References