Cooling the Grow Room Air
& Reservoir

by Mark
(North Carolina)

Would taking a frozen gallon of water leaning against the reservoir help to lower it's temp? Also, would setting a open frozen gal in front of my oscillating fan help to keep the grow zone cooler? Thanks for your help.

Answer: Mark, leaning a frozen gallon of water against your nutrient reservoir will make little difference in it's temperature. Placing a frozen gallon of water inside the nutrient reservoir would be much more effective, but it is hard to say exactly HOW effective. The larger the reservoir, the less impact the frozen gallon of water will have on the temperature of water. Also, keep an eye on the temperature of the water....having it go below 60 or 62 degrees may be just as bad as having the solution too warm.

One additional note on this....if you happen to be gardening in an unfinished basement, keeping the nutrient reservoir on the cool, concrete floor will go a long way to keeping the nutrient solution temperature in the ideal range (65-68 degrees).

This only works because there is an efficient heat exchange between the frozen gallon of water and the rest of the nutrient solution (which is in full contact with the frozen gallon). This is not the case when you put a frozen gallon of water in front of a fan. The heat exchange between the frozen gallon and the air rushing past it is very inefficient.

Especially when trying to combat the heat put off by HID lights (or even compact fluorescent lights), the only way you stand a chance at maintaining an ideal air temperature is to either bring cool air in from outdoors or else add air conditioning to the grow room. This is why so many indoor gardeners shut everything down for the Summer season. I hope this helps you out Mark, and Happy Growing!