My setup requires my exhaust to be running 24/7. As it currently stands I have my co2 tank open the entire time my lights are on. The gas is being blown across the plants before being exhausted out. I know this is wasting a lot of co2 but that aside would it be better to shut down the exhaust for 15 min and dose the plants with co2 several times a day? With the way I have it setup now blowing the co2 across the plants and being exhausted 12/12 I get a ppm reading of between 1000-2000 at any given time with the glass vial test tubes. My area is small enough that wasting the co2 is not a problem, the tanks last for 2 weeks and only cost me $7 to fill. My question is would I get better results by flooding the room with 1500 ppm of co2 for 15 min and no exhaust 4-6 times a day, or is a consistent flow of co2 over the plants via an oscalating fan while being vented 12 hours per day ok? Please explain any reasoning behind your answer.
For Co2, Co2 is used only when the lights are on. You want to feed the room Co2 for 15 minutes with the exhaust fans off... and then turn the Co2 off when the Exhaust fan turns back on. That way you saturate the room with rich Co2 and feed your babies, and your Co2 doesnt go to waste when the exhaust fan turns back on... I have 2 timers in my room... one for the fan and one for the Co2 setup. When one is on... the other is off. Unless I was told differently, I SWEAR its supposed to be Co2 only when the lights are on. However I can't explain why.
Thanks for taking the time to reply but you didn't answer my question in the slightest. I'm currently running the co2 system only when the lights are on... I understand bathing the plants in co2 in 15 min intervals uses less co2, that wasn't my question. In fact if you read my entire post I clearly explained I'm well aware that I'm wasting co2. My question is if doing it the way you just described is more beneficial then the way I'm currently set up, AND WHY.
What level are you checking your ppm? At the base of the plant? 4 feet up? 6 feet up? If you are taking your measurements at a high level, say inline with your fan, your reading of 1000 to 2000 ppm may just be from the CO2 passing by your meter and out to the exhaust. Perhaps never really giving your plants an opportunity to soak it up. If you haven't already, try taking a reading at the base of the plant. If you still get 1000 to 2000 ppm, I'd say you are good to go, if you are ok with spending 7 bucks every two weeks.
I am not an expert or have I ever used co2 but if it where me I think that shutting the exhaust off would be more effective for the plants and your wallet. If your exhaust is anything like mine I do not believe the co2 would be in long enough to make much of a difference. It was my understanding from the small ammounts I've read that it's pretty manadtory to shut the exhaust off. Good luck
It depends a lot on how air tight your grow-op is. Does the gas escape freely from cracks or crevices, or is pretty much air tight? If it isn't air tight, that should be your first step. If you can afford it, you might consider getting a Co2 controller such as this: http://www.plantlightinghydroponics...-humidity-co2-control-with-2timers-p-369.html You just plug in your ventilation into the outlet, & it turn it on & off at the timed intervals you select. Also keep in mind that the hotter your grow is, the more Co2 your plants will need. Are you using a Co2 regulator with the tubing with the small holes in it?
I can do the same thing with two $20 timers... Yes I use a controller that releases the gas in a tube. The tube, with holes punched in it, is taped the the back of an oscillating fan. The fan then blows the co2 across the canopy of the plants. My exhaust NEVER turns off. This is currently taking place the entire 12 hours the lights are on. When I take a co2 ppm test (via little glass test tube thing and syringe) I get a co2 reading of between 600 and 2000. I take the air samples from random places at random times both in the breeze of the fan and out of it. Again, my questions is..... Will stopping the exhaust fans and flooding the tent with co2 for 10-15 minutes and then restarting my exhaust a few times a day be more beneficial then they way I'm doing it now? IF SO, WHY? p.s. I have my temps under control with my exhaust running 24/7. My exhaust not only exhausts the hot air and humidity in the tent but it also passes through my cool tube. I'm not interested in completely revamping my tent at this moment in time and I'm not concerned if and how much co2 is being wasted using my method.
I would invest in a thermostat before looking at CO2 enrichment. If you need constant exhaust while the light is on, enrichment is not possible. Never trade high temps for CO2 enrichment. Never hook your room ventilation to a timer. A timer can't tell when your room is over heating or humidity is high. Maintaining room temps should be your first goal. If you can't maintain your temps without exhausting more then a few times an hour, CO2 injection will be a total waste of time. May not be the answer you want to hear.
It's not the answer I wanted to hear... I'm more then capable of shutting down the exhaust a few times a day. In the closet I have the tent is a portable a/c. It's set at 78* now but if I lower it to 72 or 70 I'm sure I could stop the exhaust for hours on end. I still want to know if shutting down the exhaust is better then the way i'm doing and why. I'm looking for facts more than opinions here. In my mind it would seem a steady flow of co2 would be better then a 15 minute bath. They might be getting less co2 but they get it all day long insted of only 3-4 times per day. Once I save up enough money for a complete co2 monitoring system I'll be placing vent holes to exhaust the cooltube with air from outside the tent and be moving to an almost sealed grow. In the mean time, with little effort, I can convert my current setup to make the exhaust stop for 15 minutes several times a day to dose with co2, IF it's more beneficial than my current setup. My temps will never go above 80* and my humidity will stay at 40-50%. So can anyone answer the question without getting side tracked on my temps, wasted co2, exhaust methods, humidity, or anything else? p.s. I have a very basic therm that will start the exhaust at a set temp. I decided not to hook it up because I don't see the need to at the moment. The system runs fine with the exhaust running 24/7 and I currently see no reason to stop the exhaust. The a/c uses much much more electricity then the exhaust, I'd rather run the exhaust longer and the a/c in short bursts UNLESS is more beneficial for my plants another way.
In order to benefit from a CO2 enriched grow room, you must maintain the levels of CO2 at 1600PPM. The plants absorb CO2 slowly throughout the "lights-on" cycle. A few minutes of high concentration will have little effect. The key is maintaining a constant tempature and CO2 level all day. If you have AC and your mind is made up that you want to inject without a controller, then your best plan is to use the AC and not your ventilation at all. Holding a constant 1600PPM is the goal for CO2 enrichment. I used to do it without a controller. I used the method that came with my regulator. Most small closet grows will set the regulator at .2 cubic feet for 15 minutes, then turn off for 15 minutes. Keep repeating this this on and off cycling while the lights are on. It is nessessary to do it every 15 minutes to keep the level constant. One or two times a day is a total waste. You will need a timer like the one below to turn on your CO2 every 15 minutes. Here is detailed instructions: http://www.hydrofarm.com/docs/19151_HF_Co2System.pdf I did it this way for two complete grows. I went through a shit load of tanks. The controller I bought paid for it's self in CO2 savings. Best of luck, you will need it.
This is more or less the answer I was looking for. This is what I thought too. I plan on adding a co2 monitor soon, but at $400 it'll take me a grow or two. They way I have it currently setup is that the co2 is being blown across the canopy all day long, the fan passes by any given plant every 5 seconds delivering fresh co2. I have my flow set at .5 and when I test the air around the plants it's about 600ppm in the 5 seconds the fan isn't blowing and 1500+ppm during and slightly after the pass of the fan. So all day long the co2 is maintained between 600-2000 ppm. Yes I do go though more co2 tanks then I would with a monitor, but at $7 per bottle to refill it would take a long time before the savings of the monitor paid for itself. One bottle will last me 1.5 weeks. About $40 per grow. It's just a lot of forums or things I've read suggests to shut down the exhaust and turn on the co2 for X amount of time Y times a day. This method makes less sense to me then the way I have mine setup. Obviously a monitor is the best method, but that's quit the investment.
It pretty much boils down to "if you can't do it right, then it's not worth doing at all". If your ventilation is going while your emitting, then your just wasting your time and your $7. It's doing more for your peace of mind then for your plants. Try singing to your plants or playing music, it can have better results for less money.
I don't understand how having the exhaust on or off has anything to do with how the plants use the co2 that is around them. I've stated several times that the co2 levels near ALL parts of the plants at any given time are from 600-2000 ppm. Yes the air is being exhausted but the co2 being exhausted is being replaced at the same speed so that shouldn't matter. I think your making to big of deal that my exhaust is running and your missing the fact that my co2 levels are SUSTAINED at 600-2000 PPM. I could understand your point if I was turning the co2 off and on every 15 min like you did, than the exhaust would pull the co2 out of the area without it being replaced. This, however, is not the case. There is always enriched co2 around my plants the entire time my lights are on. Unless the exhaust fan plays some key role in the uptake of co2 by the plants, forget about it...
As long as your fine with going through your Co2 faster than one normally would, & the Co2 is being replaced at the same rate it is being exhausted, & you get Co2 reading that are acceptable....then you are good to go. I am just saying that the CAP-2 controller pictured here will be your best bet & solve all your problems. It works like this: You plug your Co2 regulator into the plug labelled "Co2 Valve" & your exhaust fan into the outlet labelled "Exhaust outlet" You then set your frequency & duration on how often, & how long you want your Co2 to be dispensed. As soon as the Co2 kicks on, all exhaust fans stop. They do not start again until the room has reached the predetermined temperature you have set it for, with the long wire probe being the thermometer. It also has a photo sensor on it so that the Co2 will never come on with the lights out. CAP also make a Co2 reader that will piggyback onto this controller, making Co2 injection even more accurate. For around $250.00..it is the best & easiest solution fro you IMO. I bought the same model a few yrs. back, & it has served me greatly/
I have my eye on a used complete greenhouse controller w/ co2 monitor right now. If I can get it for a reasonable price I'll snatch it, otherwise this along with the optional monitor it what I had in mind after another grow or two. Saving up for a couple other things, non hobby related, atm.
So this controller doesnt have a ppm monitor. What monitor would you reccommend for this model. I'm looking for a low price without it being a piece of crap. If you don't have a ppm monitor are you basically using a formula based on the cubic feet of your room along with the desired co2 level and then hoping without really knowing you are obtaining this level in the room. I'm thinking to buy a generator, contoller and ppm monitor for a 392 ft3 room is going to run around $1200. Expensive but worth it. I realize getting a ppm monitor is the way to go but can i do it without one with some degree of accuracy using certain formulas.
It is a tough way to go or a waste not knowing the real CO2 value. The CAP model above is an expensive timer unless you add the CAP Fuzzy Logic CO2 Controller PPM-2 (another $650). Not knowing you PPM makes it hard to adjust or utilize your generator or tanks. It is almost as lame/accurate as the syringe method. A monitor will pay for it's self in wasted CO2 in time. I don't recommend CO2 enrichment in less you can invest in the over priced hardware and retrofit your grow room to a closed system. Like putting nice wheels on a Hyundai, total waste. I am into my secound monitor. This is the one installed now: CHHC-1 with remote sensor. I mounted the main unit outside the grow room. Then ran remote into the grow and hung it level with the plant tops. This unit will control humidity with your main fan/AC unit as well as temp and CO2. It cycles your fan/AC/heater/dehumidifier/humidifier if your humidity or heat goes above your set point. Seperate adjustments for everything. You can plug it into your PC and get all scientific and shit. This one unit allowed me to get rid of all the other crap I was using to control/monitor my grow room with. The only thing it's missing is a timer. My old CO2 system is worn out. It was a Control Wizard. The unit is falling apart from light exposer. Now I can dump my Thermostat as well (will hold on to it). Best deal on this system is at hydroponics.net.
So around $650 for the CHHC-1 and another $500 for the generator, bringing the total to $1200-$1400 for a system after shipping. I imagine you would get the price of the equipment back in yield within a few harvests. I need to bone up.
I use this Co2 monitor in conjunction with the CAP Co2 controller. This unit just plugs into the CAP controller, & you then set how much PPM of Co2 you want in your grow room. Getting a generator can be very costly & is also a little conspicuous. You have the exact same cubic footage as I do for my grow-op as well, & a tank & regulator works perfectly. I go through a tank every 2 weeks, & a tank runs me $16.00. I would only consider getting a Co2 generator if I was using 4000 watts of light or more.