How much air circulation is too much?

[xantius]

I've been having MAJOR problems with algae, fungus, mold, etc in my little grow rack and it has been suggested several times that it could be due to poor air flow. I have a humidifier in the rack itself and had hoped that the movement from that would be enough air circulation, but alas, I still have problems. I've been unable to find small fans that will work in my rack, so I'm wondering if a single bigger fan will work.

So the question. How much air movement is too much? Does it become disruptive to the plants to be under constant wind? What are solutions people have implemented here successfully?

-xantius

 

[CPlantaholic]

It actually is most likely related to high mineral content in the peat you are using moreso than airflow.
Do you use the open tray method? I have barely any airflow in the open tray method and I never have any problems with algae and mold now that I thoughroghly rinse my peat. You can just soak it in tap water, squeeze it out, and repeat a few times and then use distilled water the final time.
Also, I've found that in my conditions, perlite greatly increases algae growth. In the pots/tubs that I use 1:1 peat:silica sand, I havaen't had 1 spec of algae growth since.

 

[Joseph Clemens]

Different climates would likely be affected in different ways by various methods and techniques for modifying an environment, especially an indoor environment.

Here, where it is extremely arid (low humidity), for most of the year, and during six to eight months the daytime temperatures can be 90F or higher (we've had 90F+ temps in the past few days), I was running misting humidifiers and small fans to move the air, but with the lights my plant-room temperatures were frequently well over 100F, and I had to run our central A/C to keep my plants from cooking, all this did was cause an even lower humidity in my plant-room and required me to refill the humidifiers twice per day and refill my growing trays daily (this used 20+ gallons per day).

Since my plant-room was once a small bedroom in our double-wide mobile home, I was able to build a stand and mount a 6000 CFM evaporative cooler outside, adjacent to the bedroom and attach the coolers exhaust port through the plant-room window. In order to prevent this cooler from blowing the plants off the shelves, I mounted a piece of perforated pressed board to deflect the main force of the incoming air so it first blows against the ceiling of the room. Since I began running this evaporative cooler, I no longer need to use supplemental humidifiers. The temperature stays much more comfortable and the nighttime temperature cools into the 40'sF during Winter nights and this has stimulated greatly increased blooming.

So, to answer your question - "How much air circulation is too much?"

This depends on many things. For my circumstances introducing cooled, moistened air, almost like a tornado, to my plant-room has worked out fine, but I had to deflect the full force away from my plant trays, or the plants would easily be blown right off onto the floor.