DWC Root Chilling System

I've had a hydro grow for years. I haven't done squat with nutes for a long time but I always look at ways to make the environment more hospitable.

Root temps have been an issue. I think I've developed some problems in the past that were solely related to heat.

This year I started keeping track of root temps. They run about 80-81.

Anyways, I read this article and got interested. Hydroponics :: View topic - Issue 91: Chilling The Root Zone

The prob with a chilling system is you can't use it in the room. They get hot. Law of thermodynamics. You can't get rid of heat, you can only move it somewhere else.

But by moving the res outside the room, I can use that to my advantage and passively cool it (room temps about 67).

Here's how it works:

Water cools outside the room. It passively drains in through an insulated hose.

An external pump drives the water back into the modified res. (used an overflow for an Ebb/Flow unit, brass connector from HomeDepot).

Fresh aerated water drains back through the insulated hose.

This will be timed with the pumps running the hydro, but tonight did the inaugural run just to see if it'd work, LOL.

(Last pic root temp after 10 minutes running system).

Killbud

Cool, but will it improve your yield?

74.7 is still high lol

Are you sure its cooling them? I just use forzen water bottles with some water in it... works great.

74.7 is still high lol

Are you sure its cooling them? I just use forzen water bottles with some water in it... works great.

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Well, I'm pretty sure, because I have a thermometer in the roots. It's in the pics.

I guess no one read the hydroponics article. This isn't 'put a crystal and pee in my plant' type of tech, it's real science with comparison groups.

What do you base 74 being too high? Did you see in the article where he compared growth rates vs various types of hydro? He got excellent results from DWC @ 78 degreesF even in heat sensitive plants like lettuce. I'm trying to figure out how throwing chunks of ice in your roots is a good idea given that growth rate drops dramatically when the roots are overchilled (see attached photo from Univ. of Ohio Horticulture dept). From 72 -52f the rate goes from 1.0 to zero -- not good.

I agree there's debate 'what' and optimal temp is. However, the consensus I have is anything less than 65 can stun your plants, anything greater than 80 will cause loss of oxygen and increased chance of pathological organisms.

The problem is some plants thrive in warmer temps some don't, some strains of marijuana will undoubtedly differ but the range is probably somwhere between 65-75.

Cool, but will it improve your yield?

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I'm not into kewl effects. I based this on research. Read the article and find out for yourself what effect root temps have on yield. It doesn't affect only gross plant weight but amount of natural dyes (color) the plant can express. It's all in the article.

If I wanted to test this myself I'd have to do simultaneous grows with diff root temps. I think the literature speaks for itself.

If you're growing outdoors you can't manage your environment, it's geographic and where you live is the primary variable. If you're growing in a microenviro (and let's not kid ourselves a closet is a microenvirnment) you need to optimize each part of the climate. I've learned that a grow is only as good as it's weakest link.

Whether it stands or fails it's based on good science. I see so many ridiculous ideas based on Someone Being High I'm sad more people aren't into something like this.

Oh well, grow on.

Killbud

I have found optimol res water temps in aero setups to be at no more then 70 degrees F that way when it hits the root zone its about 65-68 degrees which is perfect for roots to absorb and remain bacteria free.I dont use a chiller but have been trying a few ideas to come up with one.I have used things like frozen bottle of water do a more recent creation which involves a mini fridge and some tubing inline with my pumps.I have recently come up with an idea to use a water cooler like you get a drink fro at work with the big jugs ontop.Most have cold and hot or even room temp settings.These have a potential to be converted to cool water and have cool water on demand in the top jug.Cost would be minimal as they are easy to get.I just have to work out the final design on it and will share what I find.

I think this is a good idea FF, just be careful not to chill to low. Frankly I don't like the idea of ice. The changes are just too dramatic.

I agree with FDD, the nutes aren't the secret. The enviroment is. Now, if you don't have the luxury of an outdoor spread, you're gonna be responsible to maximizing your urban indoor grow.

It's not one part, just a part, just like air temp, vapor pressure deficit (a measurement of absolute humidity), lights, fans, co2 are a part of it.

It's the ciiiiiiiircle of Liiiiiiiife!!!

BTW, here was a temp taken without the chiller, oh ye of little faith....

Yup thats why I monitor my co2 levels to keep them at 1300-1500 ppm. My nutes at correct stage ppm, ph water everyday and adjust as need, fan moving the air, lights on light movers to mimic sun movement. Portable a/c unit set on thermomstat and a dehumidifier in the room which is seal with in take and out let fans making a negative pressure grow room.Its allabout the little things

Did you have to modify that A/C to work on a thermo? Most I've found 'reset' when off so they can't just be plugged into a timer/thermo. If you have a brand or what you did that would be great b/c the A/C I have is almost worthless the way it is.

No I use the portable kind on wheels.It has a digital thermomstat on it and a built in dehumidifier and humidifier you set the temp you want and the humidity you want and turn it on and its good to go

BTW, here are my plants. It's not like I was fukkin up LOL..

9/25

and

10 minutes ago*

(2 days into flower, Willie Nelson and StrawBerry Cough)



*rearranged for space, now running 600 + 1000w HPS

Looks good..I had a few issues my last aero grow as I wnated to reassure myself of the need for co2 so I didnt use it this round and well it cost me..The plants grew foot taller then they should have causing tipping accidents and added 2 weeks of flower time..Hers a few like 7 of the 28 grown in my aero setups I build..the bigger setup.

Yeah FF, the prob with those (and I have one) is that they freakin' reset when off. So you can't just 'fire and forget'. The next time the timer turns on the dum Ac stays off. The one I have the stupid fan is on as long as it's on whether it's cooling or not. I can watch it suck my nice Co2 down the drain... I would love one I could tie into a thermostat.

I like winter grows b/c I can cool the room off just with a temp controlled inline fan and vented lights. Now that you can run Co2 with and not replace tanks all the time!

Those aeros are a trip. Nice! 28 plants. Good size on those last pics. I have to say I lean toward seeds because the different phenotypes are cool to see. I grew AK-47 and was cool to see the results of 4 very different females (Ak won 2nd best Indica and Sativa cannibus cup, diff years).

I do like to clone b/c it helps me get a few more jars of all those fine varietals. I have 12 going now.

I like to use Co2 and start it about 2 weeks into flower. I agree, if you have active plants in an enclosed enviro it's not a luxury.

You either have to vent regularly from outside or run Co2. No other option.

It's interesting to check out my Co2 meter, even when the Co2 isn't running. Initially I can see the passive outdoor air keeping pace with the plants (runs around 400ppm). But at a certain point the plants start taking up more space and needing more Co2. The levels drop to app. 200. Once they get here, I start Co2. Iv'e tried an exp trying 600 ppm which is still a healthy dose. It was great! I got huge ass buds. There may be a 'saturation point' where increasing C02 levels gives you decreasing benefit.

(last pic, bud on 600 ppm, clone DWC)

I have ran at 1600 ppm but never saw the lit showing why it was the best.

Yeah my a/c is on its own power outlet so its fine no brekare or fuse to reset.I keep it at the need temp setting and it only comes on when needed I keep my temps close to 85 with the co2 and have dampers on my ins and out fans and those fans are on opposite co2 cycles so they come on like for 8 minutes prior to the second hour co2 injections. I run the co2 during flower only lights on though havent tried the veg stage though.

Man that's great. What kind of A/C do you use? The one I have the stupid fan stays on as long as the unit is on. If it goes off you have to reset what temp you want. Argh.

My room stays about 80-82 without the exhaust going off.

Back to the chiller. I've found that the best cooling is hourly. I run this about 3-4 minutes to change the water. Not bad!

FilthyFletch said:

Looks good..I had a few issues my last aero grow as I wnated to reassure myself of the need for co2 so I didnt use it this round and well it cost me..The plants grew foot taller then they should have causing tipping accidents and added 2 weeks of flower time..Hers a few like 7 of the 28 grown in my aero setups I build..the bigger setup.

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do u think the lack of c02 is had a differance in the plants getting so tall? im having the exact problem. i venilate 24 hours a day to make up for no co2.