Mission Critical Cooling and Humidification from the Data Center Experts.

Written by Casey Jon McKay
on February 13, 2020

When you think of cash crops, wheat, corn, sugar, or soy might come to mind. While these are the most widely planted crops in the world, cannabis is king in terms of profit. Not only does it generate more revenue than every other top-planted cash crop, it also produces more money per square kilometer. But in order to be profitable in this industry, there are numerous challenges to overcome. For over six years, STULZ has collaborated with growers to design, build and install precision climate units in grow facilities throughout the United States, offering purpose-built solutions to maximize crop yields.


A Unique Industry

In addition to legality and other regulatory constraints, engineers and growers alike face specific challenges.

Engineers are tasked with developing solutions despite:

  • Lack of design experience within the engineering community
  • Lack of HVAC experience in the operator community
  • Lack of consensus within the grower community

Growers seek to address concerns including:

  • Thermally stressed plants
  • White mold or Mildew
  • Pests
  • Cross contamination between strains or rooms
  • Economic impact of the loss of a room
  • Continuation of a strain

The demands of the grow space are as dynamic, if not more so, than the typical data center environment. STULZ engineered solutions are the best way to address the level of control that successful grow operations require.

Cannabis Life Cycle Considerations  

STULZ engineers gather data on the environmental requirements to grow a healthy and productive plant such as, transpiration rates (latent cooling), impact of elevated levels of CO2, lighting needs, and life cycle.

Cannabis Seedling Stage — Clone Room/Mother Room

Cuttings are taken from the mother plant and moved to the clone room (often referred to as the nursery). Conditions in this space are also precisely maintained to ensure that the young plants have the greatest opportunity to develop a strong root system:

  • Seedlings and clones require high humidity levels of 65% - 70%
  • High humidity levels allow water intake through leaves
  • Lights on temperatures 68ºF - 77ºF
  • Lights off temperatures 59ºF - 68ºF
  • Seedlings are sensitive to light and temperature changes; lights are often left on 24 hours a day during this part of the plant’s lifecycle.

Small pests such a thrips and spider mites are especially harmful to immature plants.

Cannabis Vegetative Room

Once the plants reach a certain height they are moved into the vegetative (Veg) room. The purpose of this room is to manipulate the plants to grow tall, strong, and develop a good root bulb. Several environmental control features are manipulated to achieve this:

  • Humidity levels can typically be reduced by 5% each week
  • Temperature levels may be slightly increased
  • Roots absorb more water
  • Evaporation through the leaves cools the plants
  • Lights on temperatures 71ºF - 82ºF
  • Lights off temperatures 63ºF - 73ºF
  • Lights are on for 18 hours a day to imitate summer growing hours
  • Plants are sensitive to light and temperature changes; tight environmental control is required during this cycle

Cannabis Flowering Room

When the plants reach their optimal height they are moved to the flowering room (often referred to as the bloom room). Flowering buds are the part of the plant where many of the desirable cannabinoids are found. The goal of flowering room operations is to produce the largest flowering buds possible, as the higher the yield at this stage the more profitable.  This room requires the following characteristics:

  • Humidity levels must be lowered to 40% - 50%
  • 60% or higher humidity levels can damage crops
  • Temperatures can be slightly lowered during the flowering
  • Lights on temperatures 68ºF - 78ºF
  • Lights off temperatures 59ºF - 69ºF
  • Lighting sequence is changed to 12 hours on and 12 hours off

Cannabis Curing Room

The curing room is used for drying the cannabis in a controlled fashion to ensure the optimal final properties of the end product. Curing is critically important in maintaining the quality of the plants and typically takes a week, but the duration is dependent on many variables.

  • Environment control is required to maintain a the low temperature and low humidity
  • Ideal environmental conditions often range from 60°F - 75°F and 30 - 50% RH.

The STULZ Solutions

STULZ addresses the biggest challenge in the grow room industry by customizing the controller for precision temperature and humidity control to significantly prevent cannabis crop loss in the grow room and increase earnings. Each one is built to provide the following benefits:

  • Maximize crop yield. Advanced environmental control units maintain tight control of temperature, humidity and CO2 content at each stage of growth
  • Address relative humidity spikes during lights off cycles. Dehumidifier controls set coil temperatures low while reducing the air flow rate to maximize moisture removal
  • Heat Load Efficiency: The environmental conditions around the grow pods are kept close to grow room conditions to minimize the impact of infiltration and exfiltration on the heat and moisture load in the grow space.

Prevent the formation of white mold and mildew:  STULZ's proprietary coil temperature control system lowers the temperature of the coil to just above freezing for short periods of time to rapidly reduce the moisture content in the space. Deeper coils and drain pans are specifically designed to aid in the removal of moisture from the grow space.

  • Prevent pollen contamination. A growing pod pressure control system helps prevent pollen contamination.
  • Pest control: In some state’s regulations prohibit the use of chemical pesticides. Integral UV-C lighting coupled with oscillating fans are used to eliminate biological threats.
  • Optimized Air Circulation - Electronically commutated motor fans use little electricity and results in a 20 to 60% fan energy savings, while providing optimized pressure and balanced airflow.
  • User-friendly Controller: The E² Microprocessor is designed specifically for precision control of agricultural environments. Pre-engineered controls are designed for economizer operation.
  • Monitor CO2 for optimal growth: Growers have the option to program the E² Microprocessor Controller to monitor the levels of CO2 in the grow room.
  • Corporate and brand identity is showcased. Custom unit paint colors available

For 40 years our units have proven adaptable, scalable, available, reliable and easy to maintain and service. This means a higher cannabis yield for you at a reduced cost of operation. Growers will enjoy:

  • Properly sized equipment
  • Variable speed fans
  • Multi-stage cooling and dehumidification
  • Water side economizers
  • Hot gas/hot liquid reheat
  • Opening up the temperature humidity envelope

STULZ engineers are passionate about actively securing a sustainable future for everyone. Through our commitment to innovation, we look forward to collaborating with more growers, and increasing efficiencies of all our products, including our grow room and vertical agricultural units.

Download the full white paper to learn more about the importance of Precision Environmental Control for your grow room. 

Download the White Paper

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