i would like input on water solution temps and do you need to alter temp for different plants or different stages of groth.
If you keep nutrient properly oxygenated, 65F to 75F nutrient temp is fine.
The oxygen content of a fully aerated solution at 10C (50 F) is about 13ppm, but as the solution warms up to 20 C (68 F) the ability of the liquid to 'hold' oxygen drops to 9 - 10ppm, by the time the solution has reached 30 C (86 F), then it's only 7ppm.
Plant roots want oxygen.............
thanks willard3 that is healpfull i have airstones in tank but was unsure if i should heat it
do it goldi-locks style, not too hot, not too cold... just right. ~Ryan
What about if using Hydro outside. If the air temp gets about 80 degrees is its advisable to attempt?
ALL (well, except one) of my hydroponic creations are outside. its not problem because water has a very high "Specific Heat" it is somewhat self regulating. just paint the resivoir white and try to keep it in the shade. ~Ryan
Since I grow a lot of peppers I use a stainless steel aquarium heater set for 68 degrees (100 Watts for about 30 gallons of nutrient water). Peppers don't like to get cold, and keeping their "toes" warm seems to help.
my experience is different so I'll write it here.
I root woody tropicals in a passive(just a bucket of water) system. I ahve a bubbler and an aquarium heater.
I was having no luck getting them to put out roots until I bought the heater and set it to 85F.
This flies in the face of everything you hear about water temperature. I have a systemic fungicide to ward off pythium.
I would like to learn to lower the pH safely to keep fungus away.
So far I have had excellent luck rooting cuttings that had been stressed by fungus attack. This is much more challenging than rooting fresh cuttings. Those are easy. Those of us who grow this certain tropical are having luck with very high heat. It speeds the metabolism. When I first started, everyone said keep the water out of the sun. Well, I did but the water never got very warm and I had mixed results. Now with very warm water, I am having excellent results. Of course, it is not the same as growing lettuce so I can't speak for that.
They are also under T8 fluoros.
IMO, the only time you want warm nutes is for cloning, the cuttings do much better in tepid water, than in cold. Once the plants have set roots, you can drop the temps to mid to high 60's. Once you get above 72f, you are now getting in a situation where fusarium or pythium can gain a foothold and create all kinds of problems. Nutes at 80f, you can bet on it. To keep the reservoir cool, in the heat of the summer, mount a small computer 12vdc fan, blowing air down into the reservoir. The splashing of the returning nutes, or bubbles from an airstone, will have small water droplets in the air above the nutrient solution. The fan blowing in will evaporate these water droplets, and acting like a swamp cooler, it will drop your nutrient temps. AF of mine, in California turned me onto this, his greenhouse got to 110f regularly, so he built an isulated reservoir and, using the fan, kept his temps under control.
Bumping this up.