http://www.youtube.com/watch?v=Jxp9TL-JqVI
Urban grower from advanced nutients answering Q's on temps and controled rooms check it out they seem to have a lot of cred maybe somthing to try 58 degrees
This man is using a different technique than I am. Here is the information that I have been using for years without problems. The "commercial growers" he is talking about are caring for hundreds of gallons of water and by the time the water pump heats and distributes it to the plants it is around 70*. They jam a bunch of oxygen in a large amount of water and then plumb it quiet a distance under HID lighting. The pump adds heat, the air temp of the room adds heat to the plumbing, and the distance of the plumbing adds more heat. When the water is finally misted on the roots it has warmed considerably. I have designed setups for large scale horticultural grows and they are much more complex and expensive than what I am aiming for. Designing is what I do for a living, not commercial growing.
What temperature should my aeroponic solution be?
Why does solution temperature matter?
Dissolved oxygen, plus those competitor organisms again. At the temperature of a natural stream that is cold to the touch,
water naturally contains a great deal of dissolved oxygen. As noted above, oxygen is important to the development and productivity of a plant's feeder roots (
comprising the majority of the roots of most green plants). As water temperature approaches and exceeds 70°F/20°C, its ability to hold oxygen available to plants (and
fish) drops dramatically to only a small fraction of that of colder water. Furthermore, warmer water supports
exponentially greater cell growth in the water molds and other organisms that prey on plant roots.
Thus, a common
syndrome observed in hydroponic cultivation goes as follows. The lighting system (or sunlight, in
greenhouses), plus the
ambient air temperature, eventually bring the nutrient solution to an unhealthily high temperature: for many green plants 70°F/20°C is a warning sign, 75°F/24°C causes real stress, and 80°F/27°C can only be tolerated for a short time without causing widespread damage from which it is difficult to recover. Once a plant, and an entire growing system, is infected with water molds (e.g.
pythium spp.) it can be difficult to restore to health even after a complete change of solution or a full system cleaning.
How does aeroponics solve this?
The main advantage of aeroponics is that the
nutrient solution spends the vast majority of its time in a
reservoir, only periodically being pumped up and exposed to the relatively warm growing environment. Thus it can be much more easily maintained at a temperature that discourages
fungi (etc.) and keeps dissolved oxygen high, without resorting to expensive and high-maintenance solutions such as direct
refrigeration.
But that also describes hydroponics. What's the difference?
Good point. In a hydroponic system, every time the nutrient solution is introduced into the growing area, it interacts with the thermal mass of the solid growing medium, picking up quite a bit of heat. When air temperature is high, as it usually will be with intense lighting*, it takes very few watering cycles for the reservoir temperature to
approximate the air temperature. In aeroponics, this
heat transfer is minimized by the relative lack of medium, to such a degree that the reservoir can
feasibly be maintained at a temperature close to the nightly air temperature, or to ground temperature, instead.
*Of course lighting cooling systems are in widespread use, but they increase the complexity and expense of the setup, and everything a grower can do to decouple air temperature from water temperature tends to be to great advantage.
........
So I will maintain my room at 75* and my reservior around 68* (the water pump should heat the solution to my choice optimal of just below 70*). Without a heater the temp of my reservior drops to the high 40*s to low 50*s. The heater will maintain a constant temperature, in the summer I will route the nute solution through a coiled copper tube attached to a small fan to lightly cool the solution.
Day time temps really don't need the heater, the night time temps do.
I'm doing temp tests now on my output flow inside the tent. I will allow the reservoir temp to drop as needed to have a max of around 69* leaving the spray nozzles.
