Greenhouse Ventilation & Cooling

Greenhouse gardening allows you to maintain an even or optimum growing environment for your plants.  In order to achieve an optimum growing environment for your greenhouse plants, you must provide ventilation and cooling assistance during warmer months.

Roof and Side Venting for Your Greenhouse

  • Roof venting is the best of greenhouse ventilation systems because warm air rises. A roof vent serves as an escape route and provides a source of cool air intake.
  • Individually controlled roof vents in the greenhouse allow the intake of cool air to be a gentle flow to bench level, not a strong force that suddenly lowers the temperature.
  • Glass louvers or hinged side venting is commonly used at bench level or lower. Side venting will assist in cooling the greenhouse.

Greenhouse Shading

  • Direct sunlight during warm seasons can quickly overheat any greenhouse, possibly destroying plants and seedlings.
  • Exterior shading is the most effective method of preventing heat build-up.  Shade cloth, or screening material, has been used by commercial growers for many years, and is also available from Greenhouse Style Corporation.
  • Higher density shade cloth is more suitable for orchids or other tropicals.  Avoid plant burn, protect your plants.

Greenhouse Automatic Vent Openers

  • Automatic solar powered vent openers are self-contained units which require no electricity.  These are used on both our roof vents and side vents.
  • On a sunny day, heat will build up around the cylinder mechanism, and the vent will slowly start to open. Similarly, as the air cools around the cylinder the vent will close.
Automatic vent openers

Greenhouse Exhaust Fans

  • Will a greenhouse require an exhaust fan?  Usually, yes, an exhaust fan is required.  In addition to the roof venting and shade cloth, it keeps air moving within the greenhouse.
  • Specialty greenhouses for orchids, chrysanthemums, or tropicals, require exhaust fans to maintain a controlled environment.
  • The ideal requirement for air exchange in the greenhouse is one complete air exchange per minute.  Without this your plants may suffer from mold and mildew.
Greenhouse exhaust fan

Greenhouse Air Circulation

  • To equalize the temperature and distribute air evenly within the greenhouse, one should ensure constant air circulation.
  • Constant air circulations can greatly reduce greenhouse condensation. For best results, it is recommended to install a small fan to provide continuous movement of air.
Air circulation fan

Greenhouse Shade Cloth

  • The best way to provide cool shade and protect plants from sunburn is with an exterior  fabric shade cloth.
  • The exterior shade cloth should sit a few inches above the greenhouse glazing to avoid mold and mildew.  For this reason, never lay the shade cloth directly on top of the greenhouse glazing. An exterior shade cloth is 40% more effective than an interior shade cloth. Our shade cloth can also be cut and it will not fray.
Shade cloth