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Marijuana Bud


Too much humidity in a cannabis grow room can affect the growth and final yield as well as having implications in the spread of disease, mold, and mildew. 

You need a controlled environment to produce the best harvest. A poor growing environment lowers both yields and bud quality.




Grow Room Plant Health

By maintaining your grow room at the right humidity level, you will allow your plants to flourish. Properly sized dehumidification will help ensure that the space can achieve target humidity setpoints. This will keep an optimum environment for plant health which will maximize yields and quality while reducing plant health issues like budrot and powdery mildew.

  • Mold, powdery mildew, other plant health issues
  • Lower yields
  • Lower product quality
  • Wet spots on leaves
  • Dehumidifiers help maintain humidity in the grow space which allows plants to thrive and maximizes product quality and yields.

Grow Room HVAC Limitations

A typical air conditioner (without reheat) provides the majority of the dehumidification during “lights on”. When the lights go off, there is no longer a heat load that causes the air conditioner to run. Additionally, at colder temperatures and lower humidities, there is a capacity decrease in air conditioners and dehumidifiers. While some aim for aggressive conditions throughout the entire flowering cycle, many only drop to these setpoints during the final weeks of flower.

  • The air conditioner doesn’t provide dehumidification at night
  • Difficulty achieving colder and drier setpoints
  • Difficulty achieving colder and drier setpoints during the final weeks of flower
  • Dehumidifiers can provide continuous dehumidification without the presence of a heat load
  • Quest dehumidifiers efficiently operate at colder/drier conditions allowing you to hit setpoints
  • If colder/drier conditions are only needed during the final weeks of flower, consider using a Quest portable unit

Facility Safety

Due to the high amounts of moisture that plants put off, proper dehumidification is needed in the rooms to prevent condensation on the floors and walls. Standing water is not only a work hazard, but can also provide an environment for mold and other bacteria to grow.

  • Wet floors and other surfaces
  • Slip and fall injuries
  • Standing water
  • Air quality
  • Maintaining proper humidity will prevent condensation on the floor and other surfaces. This will make the facility safer and cleaner
  • Quest dehumidifiers use MERV filtration technology which helps remove pollen, dirt and powdery mildew from the air

Under Bench or Canopy

Healthy plants need a supply of carbon dioxide (CO2) just as they need nitrogen, phosphorous, potassium, or any other required nutrient. Often, grow rooms will add CO2 to the air so that they can maintain elevated levels of CO2 to benefit plant growth. It is important that there is sufficient airflow above and below the plant canopy so that the CO2 is spread evenly throughout the room.

  • CO2 is heavier than air and can settle underneath the canopy and benches.
  • A fan placed under the benches can help recirculate carbon dioxide and ensure uniformity throughout the grow room.

Dry Room Plant Health

The process of drying cannabis consists of removing most of the water in the bud by maintaining a humidity level between 45-60% RH. It is important to remove water in a timely manner so that the water activity is low enough to prevent mold and other bacteria from growing in the plant matter.

  • Mold, powdery mildew, and other plant health issues
  • Dehumidifiers help maintain the proper humidity levels in the dry room which allows the cannabis buds to dry out fast enough so that no mold or bacteria are able to propagate.

Dry Room Low Dew Point

Quest dehumidifiers can efficiently hit the colder/drier target setpoints commonly used in dry rooms. If conditions are too cold to use refrigerant based dehumidification, Quest has a full line of desiccant dehumidifiers that can be used.

  • Refrigerant based dehumidification stops effectively pulling out water once the dew point drops beneath 40F due to ice forming on the coils.
  • Desiccant Dehumidification can effectively pull water out at dew points below 40F.

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