Help On Optimal Temps For Sealed Room Co2

KiLoEleMeNt · Jun 18, 2015

jimmy the hat said:
me too......iv never understood why its recommended higher temps for co2...... wouldn't you want higher humidity so the stomata is fully open to better absorb the co2? I think co2 in veg is more beneficial than in flower. I too don't agree with a lot of what @KiLoEleMeNt posted...... not that it isn't useful and informative, but temps over 80? humidity under 60? co2 12-1500, high ec, no mention anywhere of vpd.... I ran those parameters for a few years when I first started growing, and I grew shitty weed.

Actually if u go back and read it I said when using c02 Relative humidity control is an essential part of insect and fungal control, as well as plant uptake and growth. Humidity above 80% and to get there u must have higher temps referring back to my RH chart pretty much everything stated is about vpd just never used the term vpd
By looking at the example we can see that at 70% RH the temperate should be between 72-79°F (22-26°C) to maintain healthy VPDs. If your growing environment runs on the warm side during summer, like many indoor growers, a RH of 75% should be maintained for temperatures between 79-84°F (26-29°C.)

The problem with running a high relative humidity when growing indoors it that fungal diseases can become an issue and carbon filters become less effective. It is commonly stated that above 60% RH the absorption efficiency drops and above 85% most carbon filters will stop working altogether. For this reason it is good practice to run your RH between 60-70% with the upper temperature limit depending on your crop's ideal VPD range, in the example it would be 64-79°F (18-26°C.)

The table also shows that if your temperature is above 72°F (22°C), 50% RH becomes critically low and should generally be avoided to minimize plant stress. Please understand that by presenting this information I do not want you to go to your indoor gardens and run your growing environment to within strict VPD values. What's important to take from this is that VPD can help you provide a better indication of how much moisture the air wants to pull from your plants than RH can. If you want to work out for yourself the VPD of your plants leaves there are plenty of charts you can get on here as well as google

As for you running this way and growing shitty weed (this may not be the case) But you may not have been providing them with what they needed to grow correctly as I stated they eat drink and transpire much more and when not givin the nessary amounts the plant Grows terrible and the co2 is wasted
Thankyou for not just calling the info crap Respect +1

KiLoEleMeNt · Jun 18, 2015

Okay, To make it further clear I will add something on VPD... so now that you have RH firmly implanted into your conceptual map, we move on to Vapor Pressure Deficit or VPD. As implied by the word "deficit" we're talking about the difference between two things. In this case, it's the difference between the theoretical pressure exerted by water vapor held in saturated air (100% RH at a given temperature) and the pressure exerted by the water vapor that is actually held in the air being measured at the same given temperature.
The VPD is currently regarded of how plants really 'feel' and react to the humidity in the growing environment. From a plant's perspective the VPD is the difference between the vapor pressure inside the leaf compared to the vapor pressure of the air. If we look at it with an RH hat on; the water in the leaf and the water and air mixture leaving the stomata is (more often than not) completely saturated -100% RH. If the air outside the leaf is less than 100% RH there is potential for water vapor to enter the air because gasses and liquids like to move from areas of high concentration (in this example the leaf) into areas of lower concentration (the air). So, in terms of growing plants, the VPD can be thought of as the shortage of vapor pressure in the air compared to within the leaf itself.

Another way of thinking about VPD is the atmospheric demand for water or the 'drying power' of the air. VPD is usually measured in pressure units, most commonly millibars or kilopascals, and is essentially a combination of temperature and relative humidity in a single value. VPD values run in the opposite way to RH vales, so when RH is high VPD is low. The higher the VPD value, the greater the potential the air has for sucking moisture out of the plant. As mentioned above, Hence the reason for high temps! VPD provides a more accurate picture of how plants feel their environment in relation to temperature and humidity which gives us growers a better platform for environmental control. The only problem with VPD is it's difficult to determine accurately because you need to know the leaf temperature. This is quite a complex issue as leaf temperature can vary from leaf to leaf depending on many factors such as if a leaf is in direct light, partial shade or full shade. Whitch is why I did not mention it. The most practical approach that most environmental control companies use to assess VPD is to take measurements of air temperature within the crop canopy. For humidity control purposes it's not necessary to measure the actual leaf VPD to within strict guidelines, what we want is to gain insight into is how the current temperature and humidity surrounding the crop is affecting the plants. A well positioned sensor measuring the air temperature and humidity close to, or just below, the crop canopy is adequate for providing a good indication of actual leaf conditions. Thus making this practice entirely and completely unnecessary.

rubthe nub · Jun 18, 2015

KiLoEleMeNt said:
2lb a light! Do you know if hydro soil ?what size pot? how many plants? RH temp? co2 ppm? maybe a link? That's outrageous!

That's not even a gpw, that's .896
Not bad numbers but DEFINITELY NOT 'outrageous'
I've beat those numbers many MANY times

KiLoEleMeNt · Jun 18, 2015

rubthe nub said:
That's not even a gpw, that's .896
Not bad numbers but DEFINITELY NOT 'outrageous'
I've beat those numbers many MANY times

And how can you be sure of that when you have no clue what size light size pot size plant???? Can't just assume without all the info I have beat those numbers too but the claim was every time not sometimes

rubthe nub · Jun 18, 2015

Pot size is irrelevant.

I assumed a 1k. Even at 6oo that's 1.49
That would have to be a hell of a run but it's certainly possible IMO
I've gotten over 1.3 several times so I'm sure it 'could' be done.
I had a couple/few 'squares' in the trellis that weren't optimal so I see that 1.5 possible

FWIW, I reread the post in question(#36) and I didn't see "every time" mentioned at all

rubthe nub · Jun 18, 2015

WTF difference does pot size make?
I reread post #36 is doesn't mention 'every time' so...........

I've done over 1.3 several times and know it could have been better.
So even if they were talking about a 600w it is still possible. That would work out to 1.49 gpw.

I'm out of this one
good luck OP

kuz · Jun 18, 2015

Pounds per light: around here people are usually talking about 1000 watts hps on 4 or 5 foot centers. Or pounds per table, usually a 4x8 with two 1000 watt lights over it.

I been thinking about the best grows I've seen in person and online and 70% and 75' to 80' is going to be my goal. I am around 80' and 50% right now.

So whats the best way to cool a 4x8 "sealed" tent. As much as you can seal a tent. I never ran co2 in a tent, but I am planning to.

KiLoEleMeNt · Jun 19, 2015

A baffled vent with a fan on a day nite thermo/ humi controler is usually the best and easiest way but I am sure there are plenty of other ways

kuz · Jun 19, 2015

I've done well with nothing but fans in a basement before. But I am struggling here, too hot and dry. I only have 1100 watts in a 4x8. A window ac blowing into the room, and a portable swamp cooler in the tent. Thats not good enough. And I need to be here all day opening and closing the tent.

I need to add a swamp cooler at the other side of the house and one of the portable ac units that dehumidifies in the tent, exhausted into the room.

I have most the stuff I need to cool it with a a water chiller and seal the tent up, its just such a cluster of pipes and valves. but I could add co2 if I go that way.

KiLoEleMeNt · Jun 19, 2015

How old are your ac units they may need a refil and the swamper may be making things harder for the ac to cool

kuz · Jun 19, 2015

ya. I do this dance, open the tent, close the door to the room, close the tent, open the door to the room. Moving the heat and humidity around.

Herb Forester · Jun 25, 2015

When I flush with co2, I use strictly the organic kind, and lots of it. More is less! You see I am a purist, no chemicals of any kind for me ever, not even in gaseous form. Never use VPD either, it can kill a plant overnight. This is something an old school tomato grower who learned it from a PhD taught me back in the day when everyone else was in diapers and your mom's 5% Woodstock weed ruled the scene. Can you smell the terps? How about the "CBD's"? Crank up that co2 until the crystals bleed resin, then back off a quarter turn.

KiLoEleMeNt · Jun 25, 2015

Oh boy we got a live one boys wachout now

KiLoEleMeNt · Jun 25, 2015

I wish I could be a pureist @Herb Forester where exactly do you get organic CO2 put in tanks that's a total new idea even for me and growing my knowlage of growing is my only life I have heard of fungus and yeast bottles and makeshift mre setups being an organic sorce for CO2 other than the air we breath in and out but that don't go in tanks unless your real talented and a chemist lol this is truly interesting would love it if you could sare with us your neat (new for me) toy

IkeTheDon · Oct 26, 2015

Hey guys good reads i do am having humidity issues just begun bloom... Been looking into dehumidifiers would it b a better choice to get better for ventilation or go for higher end dehumidifier...

300w led two fans currently one circulating air at bottom and one up top i noticed flower started leaves started to narrow i know i may need both at one point but just wanting to know which one could be a temporary fix etc....

Shrooms · Nov 7, 2015

CO2 lets you get away with more heat doesn't it? but doesn't necessarily mean optimal temp is higher....?

brianneil · Nov 7, 2015

Correct. Using CO2 increases the variable temperatures ur plants can withstand before photorespiration occurs. That does not mean the optimal temperature increases, as other factors need to be considered such as the potential consequences of increasing root zone temps - usually not good. Keep ur optimal temp the same,, if you have an unintended temp spike uv atleast buffered the plants against tissue damage

IkeTheDon · Dec 8, 2015

IkeTheDon said:
Hey guys good reads i do am having humidity issues just begun bloom... Been looking into dehumidifiers would it b a better choice to get better for ventilation or go for higher end dehumidifier...

300w led two fans currently one circulating air at bottom and one up top i noticed flower started leaves started to narrow i know i may need both at one point but just wanting to know which one could be a temporary fix etc....

Since post have moved into a house with a huge basement where the 4x4 resides and the humidity and temps are no longer an issue ready to start next grow with a few gsc autos and a few from dutch passion

Happy growing

Chance Last · Jan 25, 2016

KiLoEleMeNt said:
Ok let's see if I can't help clear the air some (pun intended) First off an accurate thermo is a must have in any indoor garden inexpensive ones are only good for collecting the most basic of information while the ideal thermo would be a day/nite or maximum/minimum type that measures the top high of the day and the lowest at nite the real expensive ones even turn on your ac/exuast and minim Temps in your room are very important (I'll explain why here) under normal conditions, the idea temperature range for growth is 72-76 degrees at not the temperature can not fluctuate more than 10-15 degrees (more like 10-12 imo) day time temperatures above 85+ degrees or below 65_ will stop growth and stunt/stress your plants out. However rooms using CO2 are different and if used correctly you can get as high as 95 degrees (NOT RECOMMENDED) Under the proper conditions witch are very demanding to maintain, higher temperatures step up metabolic activitie and speeds up growth. The warmer it is the more water the air is able to hold. This moist air often restrains plant functions and decelerates rather than speeding up growth. Other complications such as mold and pests often result from excess humidity and moisture condensation when the Temperature drops at nite. Heat buildup during warmer weather can catch you off guard and cause serious problems making proper airconditioner/heater, insulation, ventilation fans and thermostats necessary for optimal growth (dehumidifiers work just as well if it is the proper size for the room) common thermostats include single stage and two stage more more complicated controllers also regulate CO2 equipment as well as all other vents and air control devices but are not necessarily needed. temperatures can easily climb to excess of 100 degrees when poorly insulated and vented. The cold of winter is the other extreme to deal with and it's impossible to control acts of God (black outs and such) Now to brass tax

When CO2 is enriched to 0.12-0.15% (1200-1500 ppm) a temperature of 85-87 degrees F promotes a more rapid exchange of gases. Photosynthesis and Chlorophyll synthesis are able to take place at a more rapid rate causing plants to grow faster. Remember, this extra 10-15 degrees water, nutrients and space consideration, so be prepared! Carbon-dioxide enriched plants still need ventilation to remove stale, humid air out and promote plant health. Propane and natural gas heaters commonly known as CO2 generators increase temperature and burn oxygen from the air creating CO2 and and water vapor as a bi product, this dual advantage makes them practical but no more economical than CO2 tanks,I am not a big fan of heaters and don't recommend using them.
HUMIDITY
This is a big part of the equation in CO2 treated rooms. Humidity is RELATIVE! Relative humidity is the ratio between the amount of moisture in the air and the greatest amount of moisture it can hold at the same temperature. Relative Humidity is measured with a wet-dry hygrometer. When the temperature drops the humidity rises and moisture condensates on surfaces.for example an 800 cubic foot room can hold about 14 oz of water if the temperature is 70 degrees and relative humidity is at 100% . When temperature is raised to 100 degrees the same room will hold 56oz of moisture at 100% relative humidity.
Here is a basic chart to make your equations off of

A 10x10x8 room 800 cubic feet can hold 4oz at 32F, 7oz at 50F, 14oz at 70F, 18oz at 80F 28oz at 90f and 56oz at 100

Most plants grow best when their relative humidity is from 40 to 60 percent as with temperature consistent humidity promotes healthy and even plant growth. As it affects the transpiration rate of the stomata when it's high stomata close and when it's dryer they open to increasing transpiration, fluid flow and growth

So I hope this helps let me know if anything needs more explanation being as you only asked for the rite temp (which is in there) i doubt you will want to hear more droning on :) good luck

THANKYOU KILOELEMEMT! Trying to reach this same temp/humidity levels with 8k room skinny water culture. Having hard time keeping my co2 at right levels bc my ac is nonstop pushing to keep temp right! It SUCKS but I'm no Ac guy! trying to build effective return and close upsystem better. Will these chillers and King chiller or whatever help with ac cost and Usage? I am not sure what to buy and could use advice. My hoods are all closed with intake from outside room pulling thruhoods into attack. Trying to keep co2 obviously so thats what i did using 3 6 inch fans and one 8 inch can fan. The pressure is just ridiculous pushing out my ac and co2 obviously from door cracks and anywhere else possible. .ANY HELP PLEASE? ANY QUESTIONS. .I'LL CHECK BACK REGULARLY. .THANK U

KiLoEleMeNt · Jan 25, 2016

Sounds like you are not getting the negative pressure needed do you have a vacuum room for the entrance of the room? I'm not sure what to tell you that will be a great deal of help without alot of further information about your areas specs. Pm I'll try and get you some assistance with your issue but can't make any promises I can see a few minor issues that need attention by your description but it is all 200% relative of your own implementation of method. I will be awaiting your message

Help On Optimal Temps For Sealed Room Co2

Help On Optimal Temps For Sealed Room Co2

KiLoEleMeNt

KiLoEleMeNt

rubthe nub

KiLoEleMeNt

rubthe nub

rubthe nub

kuz

KiLoEleMeNt

kuz

KiLoEleMeNt

kuz

Herb Forester

KiLoEleMeNt

KiLoEleMeNt

IkeTheDon

Shrooms

brianneil

IkeTheDon

Chance Last

KiLoEleMeNt

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