Relative humidity levels of around 80% and Temperatures range of 18ºC – 24ºC (night – day, 64ºF – 75ºF)

Relative humidity in horticulture – Why ~80% RH?

Relative humidity is a critical climate parameter in the cultivation of any crop. Growers aim to maintain optimal humidity ranges, corresponding with the plants grown.

The optimal relative humidity setpoint for most plants is around 80%. At this level, growth rates are highest for common greenhouse plants. Higher or lower humidity levels may slow down physiological processes in the plant, leading to slower growth and lower quality output.

High relative humidity levels also drastically increase the susceptibility to common humidity diseases such as botrytis or powdery mildew.

Humidity is a climate parameter which needs to be understood, controlled and maintained to suit the target crops, rather than being reduced to a minimum.

Cultivation Temperature – Why 18°C (64°F)?

Most common greenhouse crops require a temperature range of around 18º-24oC (64ºF – 75ºF).

These temperatures are considered optimal for most common crops and are found in most greenhouses worldwide. Temperature setpoints are rarely set outside of this range and normally lead to slower or halted growth and suboptimal crop quality.

Controlling humidity in greenhouses and indoor growing facilities is a necessity. Untreated humidity, in such settings, leads to major problems and inefficiencies. As the crops aren’t exposed to the conditions optimal to them, they grow slower, smaller, and their quality is reduced.

Unchecked humidity will cause condensation inside any facility. The presence of this free water leads to the development of diseases such as botrytis and downy mildew, which can rapidly destroy large amounts of vegetables, Cannabis or any other crop.

Example of Water Extraction Rate Graph

The following graph presents the water extraction rate of the new DG12 EU unit, at temperatures ranging from 12oC to 24oC (64ºF – 75ºF).

DG12 EU Water Extraction Graph

The Y-axis represents water removal rates in liters per hour, while the X-axis represents relative humidity levels.

 It’s possible to see that extraction rates rise as temperature and the relative humidity rise.

Under optimal greenhouse conditions of 80% relative humidity and 18oC, the unit removes 48 liters of water per hour. At higher temperatures, the unit extracts water at a higher pace.

DryGair is Optimized for Common Greenhouse Conditions

DryGair is one of the only dehumidifier manufacturers with the sole focus of humidity control for agriculture. DG units are designed to provide optimal humidity reduction at common cultivation conditions of 18oC and 80% relative humidity, extracting more than 4 liters (1 gallon) per kWh.

As a solution for greenhouses and indoor cultivation, DryGair units are meant to operate during specific problematic periods:

Spikes in relative humidity can cause dewpoint condensation, leading to the development of various diseases. DryGair’s humidity control solution is designed to avoid these peaks, most common during dusk and dawn when conditions outdoors change rapidly.

Designed for agriculture – high water extraction rate:

All DryGair operational data is measured at 18Co (64Fo) and 80% relative humidity. Water extraction rates are faster at higher temperatures and relative humidity levels.

Click here for a comparison of all DryGiar units.