Ideal RH in the UC running CO2?

[redwhiteblue]

What do you guys prefer RH wise running 85 degree temps during light hours and 70 degrees in the dark?

 

[BudGoggles]

Well I been running mine between 50% - 65% and the plants are telling me they likey

 

[redwhiteblue]

Well I been running mine between 50% - 65% and the plants are telling me they likey

Thanks so much for your reply - What are your Day/Night temps and how many PPM of CO2?

 

[BudGoggles]

Day temps are 80-82 and night temps are 74-75 co2 peaked out at 1200 ppm now its 1100 ppm

 

[redwhiteblue]

Day temps are 80-82 and night temps are 74-75 co2 peaked out at 1200 ppm now its 1100 ppm

Sweet - mine are around 800ppm @ 84 degrees, if I bump it up to 1000-1200ppm I'm going to be hitting 90, not sure if I should go that hot w/ OG?

 

[BudGoggles]

I wouldnt go that hot with anything

 

[redwhiteblue]

Solid. Thanks for all your continued help. Staying under 85 I can get my co2 ppms up to about 890.

 

[woodsmaneh]

I run my CO2 at 1500ppm and room temps 85 on and 75 off. I run high as I found that my room is unbalanced when I run lower ppm and running at 1500ppm evens it out to around 1200ppm. Room size is 15x15x10 = 2250 sqf

You can run higher temps with CO2 as the plants will take it due to the CO2 I have my room max temp set to 93 so when it gets up there the fans come on. Here is some info on CO2

Bottom line don't worry about the 90 temp give them a little more CO2 and watch them eat way more food and water.

Hemp is a C3 plant FYI :)

Elevated CO2 Helps Reduce the Negative Impacts of High Temperatures on Plant Growth
The environmental stress about which people seem to worry most is global warming. They are concerned that the rise in air temperature that is predicted to result from a doubling of the air's CO2 content will be so great that plants will need to migrate either poleward in latitude or upward in altitude in order to remain within the climatic regimes to which they are currently adapted. And because CO2-induced warming is predicted to be so rapid, they also fear that many plants will not be able to migrate fast enough to avoid extinction.
This scenario may sound reasonable, but it is largely contradicted by a wealth of studies. In an analysis of 42 different experiments, for example, Idso and Idso (1994) found that the percentage growth enhancement due to a 300 ppm increase in atmospheric CO2 actually rose with increasing air temperature, climbing from nearly 0% at 10°C to fully 100% at 38°C, as is also confirmed by ongoing research.
Simultaneously, the optimum temperature for plant growth and development has typically been found to rise right along with the air's CO2 content. For a 300-ppm increase in atmospheric CO2, for example, theoretical and observational studies have shown that the optimum temperatures of most C3 plants rise by approximately 5°C for such a CO2 increase. This rise in optimum temperature is even larger than the rise in air temperature predicted to result from the greenhouse effect of such a CO2 increase. Consequently, it is clear that a CO2-induced warming would not adversely affect the vast majority of Earth's plants; for fully 95% of them are of the C3 variety. In addition, the remainder of the planet's species -- which may not experience as large a rise in optimum temperature -- are already adapted to Earth's warmer climates, which are expected to warm much less than the other portions of the globe. Therefore, a CO2-induced warming would not produce a massive poleward or upward migration of plants seeking cooler weather; for the temperatures at which nearly all plants perform at their optimum would rise even higher than the temperatures of their respective environments.
It is also worth noting that the photosynthetic rates in plants for which these evaluations have been experimentally derived are generally found to be nearly twice as great at their CO2-enriched optimum temperatures as they are at their optimum temperatures under ambient CO2 concentrations. Consequently, not only would typically-predicted increases in atmospheric CO2 and global air temperatures not hurt Earth's vegetation, they would probably help it, as subsequent investigations continue to suggest.
At the highest air temperatures encountered by plants, atmospheric CO2 enrichment has been demonstrated to be even more valuable; for it can often mean the difference between their living or dying, as it typically enables plants to maintain positive carbon exchange rates in situations where plants growing under ambient CO2 concentrations exhibit negative rates that ultimately lead to their demise. This life-sustaining function of atmospheric CO2 enrichment may also be partly due to a CO2-induced stabilization of heat-susceptible enzymes that is provided by the increased concentration of sugars generally found in CO2-enriched leaves. Whatever its mode of action, it is a welcome consequence of the ongoing rise in the air's CO2 content.

Box 1: The CO2-Temperature-Growth Interaction​

The growth-enhancing effects of elevated CO2 typically increase with rising temperature. This phenomenon is illustrated by the data of Jurik et al. (1984), who exposed bigtooth aspen leaves to atmospheric CO2 concentrations of 325 and 1935 ppm and measured their photosynthetic rates at a number of different temperatures. The figure below reproduces their results and slightly extends the two relationships defined by their data to both warmer and cooler conditions.

​

​

​

At 10°C, elevated CO2 has essentially no effect on net photosynthesis in this particular species, as Idso and Idso (1994) have demonstrated is characteristic of plants in general. At 25°C, however, where the net photosynthetic rate of the leaves exposed to 325 ppm CO2 is maximal, the extra CO2 of this study boosts the net photosynthetic rate of the foliage by nearly 100%; and at 36°C, where the net photosynthetic rate of the leaves exposed to 1935 ppm CO2 is maximal, the extra CO2 boosts the net photosynthetic rate of the foliage by 450%. In addition, it is readily seen that the extra CO2 increases the optimum temperature for net photosynthesis in this species by about 11°C: from 25°C in air of 325 ppm CO2 to 36°C in air of 1935 ppm CO2.
In viewing the warm-temperature projections of the two relationships, it can also be seen that the transition from positive to negative net photosynthesis - which denotes a change from life-sustaining to life-depleting conditions - likely occurs somewhere in the vicinity of 39°C in air of 325 ppm CO2 but somewhere in the vicinity of 50°C in air of 1935 ppm CO2. Hence, not only was the optimum temperature for the growth of bigtooth aspen greatly increased by the extra CO2 of this experiment, so too was the temperature above which life cannot be sustained increased, and by about the same amount, i.e., 11°C.
References
Idso, K.E. and Idso, S.B. 1994. Plant responses to atmospheric CO2 enrichment in the face of environmental constraints: A review of the past 10 years' research. Agricultural and Forest Meteorology 69: 153-203.
Jurik, T.W., Weber, J.A. and Gates, D.M. 1984. Short-term effects of CO2 on gas exchanges of leaves of bigtooth aspen (Populus grandidentata) in the field. Plant Physiology 75: 1022-1026.

 

[redwhiteblue]

I run my CO2 at 1500ppm and room temps 85 on and 75 off. I run high as I found that my room is unbalanced when I run lower ppm and running at 1500ppm evens it out to around 1200ppm. Room size is 15x15x10 = 2250 sqf

You can run higher temps with CO2 as the plants will take it due to the CO2 I have my room max temp set to 93 so when it gets up there the fans come on. Here is some info on CO2

Bottom line don't worry about the 90 temp give them a little more CO2 and watch them eat way more food and water.

Hemp is a C3 plant FYI :)

Elevated CO2 Helps Reduce the Negative Impacts of High Temperatures on Plant Growth
The environmental stress about which people seem to worry most is global warming. They are concerned that the rise in air temperature that is predicted to result from a doubling of the air's CO2 content will be so great that plants will need to migrate either poleward in latitude or upward in altitude in order to remain within the climatic regimes to which they are currently adapted. And because CO2-induced warming is predicted to be so rapid, they also fear that many plants will not be able to migrate fast enough to avoid extinction.
This scenario may sound reasonable, but it is largely contradicted by a wealth of studies. In an analysis of 42 different experiments, for example, Idso and Idso (1994) found that the percentage growth enhancement due to a 300 ppm increase in atmospheric CO2 actually rose with increasing air temperature, climbing from nearly 0% at 10°C to fully 100% at 38°C, as is also confirmed by ongoing research.
Simultaneously, the optimum temperature for plant growth and development has typically been found to rise right along with the air's CO2 content. For a 300-ppm increase in atmospheric CO2, for example, theoretical and observational studies have shown that the optimum temperatures of most C3 plants rise by approximately 5°C for such a CO2 increase. This rise in optimum temperature is even larger than the rise in air temperature predicted to result from the greenhouse effect of such a CO2 increase. Consequently, it is clear that a CO2-induced warming would not adversely affect the vast majority of Earth's plants; for fully 95% of them are of the C3 variety. In addition, the remainder of the planet's species -- which may not experience as large a rise in optimum temperature -- are already adapted to Earth's warmer climates, which are expected to warm much less than the other portions of the globe. Therefore, a CO2-induced warming would not produce a massive poleward or upward migration of plants seeking cooler weather; for the temperatures at which nearly all plants perform at their optimum would rise even higher than the temperatures of their respective environments.
It is also worth noting that the photosynthetic rates in plants for which these evaluations have been experimentally derived are generally found to be nearly twice as great at their CO2-enriched optimum temperatures as they are at their optimum temperatures under ambient CO2 concentrations. Consequently, not only would typically-predicted increases in atmospheric CO2 and global air temperatures not hurt Earth's vegetation, they would probably help it, as subsequent investigations continue to suggest.
At the highest air temperatures encountered by plants, atmospheric CO2 enrichment has been demonstrated to be even more valuable; for it can often mean the difference between their living or dying, as it typically enables plants to maintain positive carbon exchange rates in situations where plants growing under ambient CO2 concentrations exhibit negative rates that ultimately lead to their demise. This life-sustaining function of atmospheric CO2 enrichment may also be partly due to a CO2-induced stabilization of heat-susceptible enzymes that is provided by the increased concentration of sugars generally found in CO2-enriched leaves. Whatever its mode of action, it is a welcome consequence of the ongoing rise in the air's CO2 content.

Box 1: The CO2-Temperature-Growth Interaction​

The growth-enhancing effects of elevated CO2 typically increase with rising temperature. This phenomenon is illustrated by the data of Jurik et al. (1984), who exposed bigtooth aspen leaves to atmospheric CO2 concentrations of 325 and 1935 ppm and measured their photosynthetic rates at a number of different temperatures. The figure below reproduces their results and slightly extends the two relationships defined by their data to both warmer and cooler conditions.

​

View attachment 277384​

​

At 10°C, elevated CO2 has essentially no effect on net photosynthesis in this particular species, as Idso and Idso (1994) have demonstrated is characteristic of plants in general. At 25°C, however, where the net photosynthetic rate of the leaves exposed to 325 ppm CO2 is maximal, the extra CO2 of this study boosts the net photosynthetic rate of the foliage by nearly 100%; and at 36°C, where the net photosynthetic rate of the leaves exposed to 1935 ppm CO2 is maximal, the extra CO2 boosts the net photosynthetic rate of the foliage by 450%. In addition, it is readily seen that the extra CO2 increases the optimum temperature for net photosynthesis in this species by about 11°C: from 25°C in air of 325 ppm CO2 to 36°C in air of 1935 ppm CO2.
In viewing the warm-temperature projections of the two relationships, it can also be seen that the transition from positive to negative net photosynthesis - which denotes a change from life-sustaining to life-depleting conditions - likely occurs somewhere in the vicinity of 39°C in air of 325 ppm CO2 but somewhere in the vicinity of 50°C in air of 1935 ppm CO2. Hence, not only was the optimum temperature for the growth of bigtooth aspen greatly increased by the extra CO2 of this experiment, so too was the temperature above which life cannot be sustained increased, and by about the same amount, i.e., 11°C.
References
Idso, K.E. and Idso, S.B. 1994. Plant responses to atmospheric CO2 enrichment in the face of environmental constraints: A review of the past 10 years' research. Agricultural and Forest Meteorology 69: 153-203.
Jurik, T.W., Weber, J.A. and Gates, D.M. 1984. Short-term effects of CO2 on gas exchanges of leaves of bigtooth aspen (Populus grandidentata) in the field. Plant Physiology 75: 1022-1026.

If I read this correctly, the study is claiming that foliage production rates increased by 450% at 97 degrees with 1935ppm of CO2?

 

[woodsmaneh]

Yup that's what they got but your mileage may vary lol. I get about 20% more using CO2 and my water and food use almost goes up by 30%.

To get the max out of CO2 you need to have everything else dialed in and than you will get much higher yields from your garden. The big mistake people make when they come into my shops is expecting to install CO2 and get 50% more LOL, they come back and say it did not work. You need to have a good handle on nutrients, air, light, humidity, water, pH and temps to get the full impact with CO2, when you do the pay off is great.

 

[tipper619sd]

Yup that's what they got but your mileage may vary lol. I get about 20% more using CO2 and my water and food use almost goes up by 30%.

To get the max out of CO2 you need to have everything else dialed in and than you will get much higher yields from your garden. The big mistake people make when they come into my shops is expecting to install CO2 and get 50% more LOL, they come back and say it did not work. You need to have a good handle on nutrients, air, light, humidity, water, pH and temps to get the full impact with CO2, when you do the pay off is great.

well said woodsmaneh . Especially for a new guy whos looking to research on the co2 game thanks all you guys for this thread

 

[woodsmaneh]

A little more info for you

Peace and merry Christmas :cool:



More CO2 Means More Plant Growth

Herbaceous Plants​

Woody Plants​

Aquatic Plants​

Perhaps the best known consequence of enriching the air with CO2 is that plant growth and development is enhanced. This is because, at a fundamental level, carbon dioxide is the basis of almost all life on Earth; it is the primary raw material utilized by plants to produce the organic matter out of which they construct their tissues. Consequently, the more CO2 there is in the air, the better plants grow, be they terrestrial or aquatic. Such has been the conclusion of literally hundreds of laboratory and field experiments conducted over the years.
For an approximate doubling of the air's CO2 content, the wealth of data that has been accumulated over decades of meticulous research has convincingly demonstrated that the growth or productivity of most herbaceous plants rises by about a third, while that of most woody species increases by 50% or more. It should come as no surprise, therefore, that the father of modern research in this area -- Dr. Sylvan H. Wittwer -- has stated that "it should be considered good fortune that we are living in a world of gradually increasing levels of atmospheric CO2."

​

Reference
Wittwer, S.H. 1997. The global environment: It's good for food production. In: Michaels PJ (ed) State of the climate report: Essays on global climate change. New Hope Environmental Services, New Hope, p 8-13.
** Individual plant growth responses to increasing atmospheric CO2 may be viewed online at the Center for the Study of Carbon Dioxide and Global Change in its Plant Growth Database (http://www.co2science.org/data/plant_growth/plantgrowth.php), which is the largest repository of such information in the world on this subject.


Rising CO2 Boosts Plant Water Use Efficiency
More CO2 Means Less Water Stress for Plants
Another major benefit of atmospheric CO2 enrichment is that plants exposed to elevated levels of atmospheric CO2 generally do not open their leaf stomatal pores - through which they take in carbon dioxide and give off water vapor - as wide as they do at lower CO2 concentrations. In addition, they tend to produce less of these pores per unit area of leaf surface at higher levels of atmospheric CO2. Both of these changes tend to reduce most plants' rates of water loss by transpiration; and the amount of carbon they gain per unit of water lost - or water-use efficiency - therefore typically rises, greatly increasing their ability to withstand drought.
The reduction in leaf evaporation rate produced by this phenomenon can be as much as a third for a doubling of the air's CO2 content; and combining this effect with the simultaneous 30 to 50% CO2-induced increase in plant productivity, which is described in More CO2 Means More Plant Growth, dramatically increases the efficiency with which individual leaves utilize water to produce organic matter. In many cases, in fact, a doubling of the atmospheric CO2 concentration actually doubles leaf water use efficiency.
A second way by which atmospheric CO2 enrichment improves plant water relations is by increasing plant turgor, which is essential for proper vegetative growth and development. Very briefly, this phenomenon begins with a CO2-induced increase in leaf carbohydrate concentration, which then enhances leaf osmotic potential and ultimately helps to maintain adequate leaf water contents for continued photosynthesis and growth in the face of declining soil moisture availability.
The many ramifications of these several atmospheric CO2 enrichment effects on plant water relations are truly impressive. As the atmosphere's carbon dioxide concentration rises ever higher in the years ahead, nearly all plants should be able to grow where it is presently too dry for them, enabling the most drought-resistant species to reclaim great tracts of land previously lost to desertification. Greater vegetative cover should also reduce the adverse effects of soil erosion caused by the ravages of wind and rain.


Elevated CO2 Helps Plants Cope With Low Levels of Essential Resources

Light​

Water​

Nutrients​

Adequate levels of light, water and nutrients are needed for good plant growth. Hence, it might logically be assumed that the growth-promoting effects of atmospheric CO2 enrichment would be reduced when these essential resources are present in less-than-adequate amounts. As shown in the sections below, however, hundreds of experiments have clearly demonstrated that such need not be the case.
In many instances, in fact, the percentage growth enhancement provided by atmospheric CO2 enrichment is even greater when these important natural resources are present in sub-optimal quantities; and when they are in such short supply that plants cannot survive under current atmospheric CO2 concentrations, elevated levels of CO2 often enable such vegetation to grow and successfully reproduce where they would otherwise die.

See part 2 below

 

[woodsmaneh]

Part 2 ^^^^



Rising CO2 Enhances Plant Resource Acquisition

The Role of Roots​

Nitrogen-Fixing Bacteria​

Symbiotic Soil Fungi​

Carbon Starvation​

One of the reasons why plants are able to respond to atmospheric CO2 enrichment in the face of significant shortages of light, water and nutrients is that CO2-enriched plants generally have more extensive and active root systems, which allows them to more thoroughly explore larger volumes of soil in search of the things they need. In the case of legumes, which are found in almost all of Earth's ecosystems, atmospheric CO2 enrichment additionally helps the nitrogen-fixing bacteria in the nodules of their roots to remove more nitrogen from the atmosphere and make it available to their hosts.
Symbiotic soil fungi attached to plant roots also function better when their hosts supply them with more photosynthetically-produced substances, as nearly all plants typically do in CO2-enriched air. These fungi then repay their hosts by supplying them with extra water and nutrients. They also produce hormones that further stimulate root growth; and they help to protect their hosts from toxic materials in the soil and from soil-borne plant pathogens.


Elevated CO2 Helps Plants Survive Environmental Stresses

Soil Salinity​

Air Pollution​

High Temperatures​

Low Temperatures​

There are a number of environmental stresses that can severely restrict plant growth and development; but they have little detrimental impact on the benefits provided to such plants by atmospheric CO2 enrichment. In the case of soil salinity, for example, the percentage growth enhancement due to an increase in the air's CO2 content is about the same in both salt-stressed and non-salt-stressed plants. In the presence of harmful air pollutants, on the other hand, the percentage growth enhancement produced by atmospheric CO2 enrichment is typically even greater than it is in non-polluted air. And as air temperatures rise higher and higher, so too do the relative benefits of elevated CO2 concentrations rise higher and higher. At the point where plants normally succumb to thermal death, in fact, the presence of high CO2 levels often helps them to survive, where normally they would wither and die.
The preferred or optimum temperature for growth in most plants also rises with an increase in the CO2 content of the air; and it generally rises even faster than the rate of global warming that is typically predicted to accompany an increase in atmospheric CO2. Consequently, and contrary to the claims of many people who are unaware of this fact, if there were ever to be a CO2-induced warming of the globe, there would be no mad rush of plants to keep up with the poleward shift of the climatic regimes to which they are currently accustomed. And there would likewise be no extinctions of migratory laggards!
At the other end of the temperature spectrum, there are a number of ways by which atmospheric CO2 enrichment may mitigate chilling injury to plants. Higher CO2 levels also help plants to better withstand air-borne and soil-borne plant pathogens; and, in the mean, they help crops somewhat more than they help the weeds that compete with them. Insects will probably always be a problem, even in a CO2-enriched world; but with the greater levels of vegetative productivity that are typical of such an environment, there should be more organic matter available to accommodate them, so that Earth's plant life should not suffer any worse in this regard than it does now.

Elevated CO2 Helps Plants Survive Biological Stresses

Weeds​

Insects​

Disease​

Herbivory​

There are a number of biological stresses that can severely restrict or harm plant growth and development; but they have little detrimental impact on the benefits provided by atmospheric CO2 enrichment. In the case of weeds, for example, an increase in the air's CO2 content should provide no competitive advantage against non-weeds. Insects will continue to do their damage; but percent destruction will likely not change.
The same can be said about the negative effects herbivory. Plant diseases, on the other hand, should have less of an impact in a CO2-enriched atmosphere of the future, as rising CO2 concentrations help plants become better equipped to successfully deal with pathogenic organisms and the damage they have traditionally inflicted.

 

[Camnibus]

I shut it off after about week four, my room's at 82',55-60%rh, 68' rez/water. After the first month in flower, they only seem to develope more leaf, not bud.
I've tried it both ways, running co2 all the way through and turning it off after week 4 or so (same THC Snow strain) It's like 2 different plants. Buds are about the same size, but the amount of junk leaf is substantially reduced without co2 for the last month.
Something I'm doing wrong or is this normal?

 

[bigdaddyg8]

i shut the co2 off week 8 of a 10 week strain . weeks 1-8 start at 60%rh end 40% rh by week 8 and maintain 40% rh till finished .water temp 65 - 68 deg , 85deg lights on .68deg light off .

 

[redwhiteblue]

i shut the co2 off week 8 of a 10 week strain . weeks 1-8 start at 60%rh end 40% rh by week 8 and maintain 40% rh till finished .water temp 65 - 68 deg , 85deg lights on .68deg light off .

What PPM, what strain, how tall/wide are your plants, which UC/lighting system, and what do you yield in dry weight?

 

[redwhiteblue]

Yup that's what they got but your mileage may vary lol. I get about 20% more using CO2 and my water and food use almost goes up by 30%.

To get the max out of CO2 you need to have everything else dialed in and than you will get much higher yields from your garden. The big mistake people make when they come into my shops is expecting to install CO2 and get 50% more LOL, they come back and say it did not work. You need to have a good handle on nutrients, air, light, humidity, water, pH and temps to get the full impact with CO2, when you do the pay off is great.

What ppm are recommending to run for OG veg and flower?

 

[LexLuthor]

Great read Woodsmaneh.

 

[woodsmaneh]

I only run CO2 during Flower and I run it 8 weeks on a 9 week strain, they get just regular air for the last 7 to 10 days.

What ppm are recommending to run for OG veg and flower?​

I would run at 1000ppm and keep an eye on them, I have used CO2 for 14 years and much like everyone who comes into the shops I thought it was a magic bullet and did not get much out of the CO2 for about 6 months. I had to get my other important things like food, water, air and the like sorted out than I saw a 20 to 30% gain in yield. I don't like to put percents down as not everyone can replicate what I do. I would say about 75% of people who use CO2 are disappointed but that is because they don't sweat the details and it's all about the details.​

 

[BudGoggles]

So 1k ppm is a good number to be at for flower with co2. Im in the process in dialing in my sealed room just finished my first run and I seen a huge difference with co2 . I hear a lot different opinions on co2 ppms