Read the inspiration behind installing a MicroCool fog humidification system at a propagation greenhouse as told by Roger McGaughey, Head Grower, Pioneer Gardens. Keeping the environment just right in terms of temperature and moisture for cuttings is crucial. Not only does the humidity level need to be consistent, but the cuttings and soil, or medium, can’t be too wet, either, so that condensation does not pool.

Roger covers balancing conditions so that VPD is kept consistent by temperature, air flow and amount of humidity utilizing a MicroCool fog system within a greenhouse environment. Like most work where natural conditions can require constant tinkering or adjustments, the MicroCool system allows for incremental increases and decreases in temperature in order to meet the humidity set point along with easy directional nozzle adjustments.

Managing Ideal Greenhouse Conditions For Plant Propagation

One of the most important considerations when attempting to successfully manage a propagation department is to provide just the right amount of water to keep the cuttings turgid. Too much water, or over-misting, leads to serious disease problems and rotting of the cuttings. Under-misting leads to stress, tissue damage and shrink due to lack of rooting.

…to successfully manage a propagation department is to provide just the right amount of water to keep the cuttings turgid.

We, like many other propagators, have experienced the bad and the good. In my early days at Pioneer, we were trying to propagate unrooted cuttings in conditions that were far from ideal. We had mist booms, VPD and shade, but in the large area that was our prop house, we were fighting a losing battle. We were still over-misting our cuttings. So how to fix the problem and start eliminating shrink? We installed new oscillating fans controlled by our Argus environmental computer to increase the overall zone humidity. These helped, but the moisture fallout from the fans still didn’t produce ideal conditions.

As usually happens in spring when production is ramped up, we ran out of room. So when we had to expand our prop facilities into another house, we were back to square one. At this time, while discussing the extra humidity benefits the J-Bird fans were giving us, I told Jaap (my boss) of an experience we had while climbing in the Lake District when we lived in England.

Choosing a Greenhouse Humidity System: The Fog of Inspiration

My family and I were climbing a mountain in bright sunny weather, but as we neared the summit, conditions changed and we were soon surrounded by fog. As we leveled out at the top, visibility was just about zero. All of a sudden the breeze increased and a small lake appeared in front of our eyes. Magic! As quickly as the breeze came up, it dropped, and the lake disappeared again. The moral of that story was “we need a fog system for our prop.” Jaap liked that idea and asked where we could get one and how much would it cost.

It just so happens that a friend of mine from England, Mark Stanley, works for MicroCool in Palm Springs. They specialize in all types of humidity applications. I reached out to him with a lot of questions and explained our situation. After several conversations, Mark agreed that they could help solve our problems. He produced a design, the price was right and we purchased a customized fog system for our second propagation area.

There were some initial operational difficulties with fog dispersal. To make installation easy, we had the fog lines supported near the pathway of our 7,000-sq. ft., two-bay prop area with the nozzles all pointed in the same direction in each bay. We used our HAFs to disperse the fog, but this caused some moisture fallout in the first few feet from the nozzles, making cuttings in that area far too wet. Taking this into consideration and wanting to make facility adjustments, we eventually moved our prop department and fog system into two bays adjacent to our transplant line. Read entire article here. (1)

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(1) Article Originally Published by GrowerTalks.

McGaughey, Roger. “Propagation Fog System.” GrowerTalks, Ball Publishing. Volume 80, No. 11. February 2017. Web.


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