fans

[dendro photo]

should i leave the fans run on my plants at all times?

[BobInBonita]

What are your conditions? Do you think it is too hot? Do you think it is too humid? Why do you want to use a fan? Understanding your conditions is the key to answering your question.

A fan (without evaporation) does not change the humidity if that is your potential issue. It does move air around, and in "borderline" situations that is like increasing the surface area of the plant. The more surface area, the more evaporation that can occur. Evaporation means there is more moisture in the air, i.e. more humidity.

A fan does not provide any real cooling unless there is evaporation. When water evaporates it cools the surface that it evaporated from, and as a result the air temperature. But evaporation increases the humidity. It the evaporation occurs from a leaf surface, the plant dries and cools. If the evaporation occurs in a mist (as in a mist cooler) the air is cooled. Either way, the water winds up in the air and that means the humidity is higher.

A downside of a fan is that, as above, it moves air. If you have a mold or fungus issue, it will move spores around. Are you thinking about an exhaust fan that would blow the spores out? Where would the air come from? Wil the "replacement" air be of better quality (cleaner or of lower temperature, humidity) than the "inside" air?

Fans can really work wonders, but only if you know your system, what you want to achieve, and can use them in a way that works for you.

Sorry if I came off as lecturing, but I just had a personal failure to think things through with my own growing conditions. I have orchids outside hanging in a large guava bush/tree. The branches were hanging lower and lower because of the weight. All of the orchids had been slowly positioned to recieve optimal light for their own needs. (Phals in deep shade, dend with a little more light, cats near the edges with high light, and vandas on the outside with some direct sun.) On a cloudy day I transferredseveral plants to a new rack system I am building, without realizing how much the change inweight would affect the light. The next day I looked out after dinner to see several dends and two phals severely sunburned. You always have to try to understand your own system, and what you are trying to do, or the best intentioned advice can lead you down the wrong path. Always ask for the advice. Always listen to the advice openly. Only act based on your knowledge or your system.

[johnblagg]

air movement from what I understand is essential ....

1 - it does move spores around but that is actually good moving spores are not sitting on medium or leaves actually germinating

2 - with no air movement carbon dioxide gets depleted in the area around the leaves and since carbon dioxide is heavier than other gases will settle towards the floor so air movement makes sure it is well distrubted .....and orchids do most of their gas exchange at night too.

3 - it does help to air move through your medium as well....even the roots need to breath

rather than turn your fan off at night perhaps just lower the speed at which it runs...I leave a small fan on at all times for mine

[dendro photo]

I am only running a small fans (2X 5 inch component fan) to keep air moving i have a very small indoor "green house" just to keep cats and birds away but in turn ther is no air movement the fans blow new air in and old air out continually i mist in the morning to keep hummidity and water when needed. i dont think temp is a factor, and sometimes i need a good lecture

[CTB]

I keep a small fan on, for my few indoor plants, only because they are enclosed in a small room without air flow. The fan does the trick, it moves the air, and has some cooling properties.