[Carbon Dioxide] & Root Growth
- Thread starter ChinaVoodoo
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Curious study. Thanks for posting it.
I'm not sure what the implications of that study might be for tobacco growers. If there is inadequate nitrogen in the soil, and the ambient CO₂ is twice what is normal, then the leaf will show increased starch production, but not increased sugar production (compared to other nitrogen deficient plants in normal CO₂), but not grow any better than any nitrogen deficient tobacco. Meanwhile, the root system loves the elevated CO₂, and proliferates. Do these happy roots then produce more alkaloid or less alkaloid? Do they render the above-ground portion of the plant sturdier or more disease resistant? Are stalks and leaves stunted? Will the leaf be easier or more difficult to color-cure and subsequently age? How will these conditions affect the burn, aroma and taste of the finished leaf?
We may all get to discover the answers to those questions.
Bob
I'm not sure what the implications of that study might be for tobacco growers. If there is inadequate nitrogen in the soil, and the ambient CO₂ is twice what is normal, then the leaf will show increased starch production, but not increased sugar production (compared to other nitrogen deficient plants in normal CO₂), but not grow any better than any nitrogen deficient tobacco. Meanwhile, the root system loves the elevated CO₂, and proliferates. Do these happy roots then produce more alkaloid or less alkaloid? Do they render the above-ground portion of the plant sturdier or more disease resistant? Are stalks and leaves stunted? Will the leaf be easier or more difficult to color-cure and subsequently age? How will these conditions affect the burn, aroma and taste of the finished leaf?
We may all get to discover the answers to those questions.
Bob
ChinaVoodoo
Moderator
My guess is that this demonstrates that because there is more starch in roots, that the discovery is that atmospheric CO2 is still used, even if there's low nitrogen. Question, If nitrogen is normal, is the CO2 not biased to the roots, and does the entire plant benefit? I am aware that growers of other plants use CO2.
I built a grow tent, and am considering using sugar fermentation to provide CO2.
I built a grow tent, and am considering using sugar fermentation to provide CO2.
I believe the study demonstrated that, under their defined conditions, the leaves manufactured more starch in the elevated CO₂ scenario. It does suggest that the nitrogen deprived, CO₂ elevated plants might be less likely to blow down in gusty winds.
Bob
Bob
What is the size of the tent and how much ventilation do you have?
I have a 2×4×6 foot tent (60×120×180cm).
The volume of my tent is 48 cubic foot (1.3m2).
The ventilation is 63ft3/min (107m3/hour).
This means that the air is exchanged at a rate of 1.4 times the tent volume per minute.
Someone smarter than me can calculate how much CO2 one need to raise the CO2 level from 400ppm to 800ppm with such a setup but my estimation is that yeast and sugar will not produce enough for it to be noticeable for the plants.
The general opinion seem to be that CO2 enrichment is only usable for rooms/greenhouses without ventilation.
In a closed room the CO2 level can be raised above what is normal on earth today.
According to the well of knowledge aka Google, the CO2 level was much higher 500 millions of years ago, exactly 3000-9000ppm.
I guess the plants had their prime time then.
I have a 2×4×6 foot tent (60×120×180cm).
The volume of my tent is 48 cubic foot (1.3m2).
The ventilation is 63ft3/min (107m3/hour).
This means that the air is exchanged at a rate of 1.4 times the tent volume per minute.
Someone smarter than me can calculate how much CO2 one need to raise the CO2 level from 400ppm to 800ppm with such a setup but my estimation is that yeast and sugar will not produce enough for it to be noticeable for the plants.
The general opinion seem to be that CO2 enrichment is only usable for rooms/greenhouses without ventilation.
In a closed room the CO2 level can be raised above what is normal on earth today.
According to the well of knowledge aka Google, the CO2 level was much higher 500 millions of years ago, exactly 3000-9000ppm.
I guess the plants had their prime time then.
ChinaVoodoo
Moderator
My tent is not totally sealed and ventilation is passive.
Years ago I noticed a dramatic difference in aquarium plant growth by putting about 4 bubbles of co2 per minute into the filter where it would dissolve.
Years ago I noticed a dramatic difference in aquarium plant growth by putting about 4 bubbles of co2 per minute into the filter where it would dissolve.
ChinaVoodoo
Moderator
And it didn't kill the fish.
If I understand correctly the plants can tolerate more light and more heat with added CO2 but if the CO2 is not a limiting factor for growth the effect on growth by adding CO2 is minimal.
It is hard to tell if CO2 is the limiting factor without full information about the grow.
I don't understand what you mean by passive ventilation, do you have the tent open or closed?
It is hard to tell if CO2 is the limiting factor without full information about the grow.
I don't understand what you mean by passive ventilation, do you have the tent open or closed?
ChinaVoodoo
Moderator
It's open a quarter inch at the bottom and the door isn't sealed, it's just overlapping. There's also a 1/2" hole at the top where the power cord goes through.
Ok then I guess it is almost sealed, don't you have a problem with heat?
I did grow with passive ventilation but then I kept the tent wide open at all times, it was a success but now I have added proper ventilation.
Typically grow tents are ventilated by an extraction fan at the top and new air is sucked into the tent through ventilation holes at the bottom. That way the CO2 level never dips.
I know that it is possible to grow in a sealed room by adding a lot of CO2 but it is not very common and these types of grows are very advanced.
I think you should look at all the factors limiting growth, the soil and nutrients, the humidity, the light and the CO2 level. Then you improve them all together to make the plants happy.
So basically you got two options, add ventilation to keep the CO2 level high, to remove heat and keep humidity low or add CO2 and manage heat and humidity problems by other means.
It is way easier to add ventilation than to add CO2 and fix the heat and humidity problem by other means.
Do you plan on starting a grow blog here?
ChinaVoodoo
Moderator
Yes, I do.
I always just grew on the counter, but I was just at the hydro store the other day and the gentleman there made me realize that 200W that isn't metal halide or sodium will be fine in a tent such as mine without ventilation. It wasn't an intellectual conversation. It was me simply looking at and in their tents, avec living plants inside them, and saying, hey, I thought you needed a ventilation fan.
Also, my tent is 74° with four 48" T5 fluorescent bulbs.
It sounds to me like your ratio of bulb to space is greater than mine.
I honestly don't want to perfect the system. This is temporary every year until the greenhouse is warm enough.
I know I've been poisoned by CO. Gases will build up. How much? I can't say. I understand the impulse to quantify and verify. I think I will rely on my intuition and experience to guess whether it's working or not and worthy of further investigation.
Thanks for the advice. I appreciate you putting serious thought into my musings. I wish I had the personality for a comprehensively cataloged seedling grow. I know myself. I don't.
This is my 10th grow. I'm sure I'll get some plants into the dirt.
Very nice store but maybe they grow with the tents open in the store?
I have 220 Watt in a 4×2 foot tent. It is ok to grow without fans but I would never close the tent without fans, it will suffocate the plants.
The plants also need some air movement to remove CO2-depleted air from the underside of the leaves.
I have 220 Watt in a 4×2 foot tent. It is ok to grow without fans but I would never close the tent without fans, it will suffocate the plants.
The plants also need some air movement to remove CO2-depleted air from the underside of the leaves.
ChinaVoodoo
Moderator
Now that I think of it, the holes where the fans would go were open. Not like a big open circle but more like a turtle neck. The lights were below the holes.
And the door was open too!
ChinaVoodoo
Moderator
I'm sure I wasn't clear on it. The doors were closed, we unzipped them to see inside.
Ok! Cool shop!
Then I guess he had all three air intake holes at the bottom open.
I suggest you open everything if you want to try passive ventilation, you want the warm air to go out at the top and cool air to go in at the bottom so remove the three covers for the ventilation holes at the bottom and open the round ventilation-hose holes wide open.
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Enriching CO2 negates the need to ventilate with fresh air, UNLESS you are trying to control temperature.
Bringing CO2 up to 1200ppm causes dramatic growth in tomatoes and 'other' similar plants. It also helps plants' heat tolerance.
I had planned on running some tubing into a small germination tray from a small bottle of a fermenting mash, just to see if I could help them along with the slow start I see in a lot of the grow blogs.
I also notice that fertilizer is to be stopped as leaves ripen, and I wondered if a container-grown plant could be (gently) pulled from it's container, and placed in a bucket of clean water, and agitated until the dirt is pretty much gone, then place the plant in a bucket of clean water, with an air stone at the bottom, so the plant would have virtually no nutrients, and see how this would affect ripening and color curing.
In northern Germany, I should get the 90 frost free days, but, trying to color cure in the cold, dry weather I'm bound to have, is leading me down strange hypothetical routes....
Bringing CO2 up to 1200ppm causes dramatic growth in tomatoes and 'other' similar plants. It also helps plants' heat tolerance.
I had planned on running some tubing into a small germination tray from a small bottle of a fermenting mash, just to see if I could help them along with the slow start I see in a lot of the grow blogs.
I also notice that fertilizer is to be stopped as leaves ripen, and I wondered if a container-grown plant could be (gently) pulled from it's container, and placed in a bucket of clean water, and agitated until the dirt is pretty much gone, then place the plant in a bucket of clean water, with an air stone at the bottom, so the plant would have virtually no nutrients, and see how this would affect ripening and color curing.
In northern Germany, I should get the 90 frost free days, but, trying to color cure in the cold, dry weather I'm bound to have, is leading me down strange hypothetical routes....
When you do this to a 10 pound, 6 foot tall plant with stiffening, mature leaves spanning 4 feet, please post a video of it.
Bob
Hence the plan to try this out on a pot-stunted Xanthi!
With help, and a ladder, I've done it with several ficus trees. I worked in a hydroponic shop for 2 years, and we would take 10'+ ficus trees and get them into 5 gallon bucket systems. They would grow to about 20' before they broke the bucket with their root mass.
I’ve done CO2 enrichment with fermentation on my tobacco seedlings- those that received it, showed secondary leaves at least a week faster than those that didn’t.
If you don’t want to mess around with fermentation, you could always quickly generate CO2 with vinegar and baking soda (sodium bicarbonate).
14.3 grams of vinegar (5% acid) per gram of sodium bicarbonate should give a balanced reaction, with no waste of either material, generating CO2 whenever you need it.
I used a 1 liter batch of sugar and corn flakes and piped the gas into a 1liter bottle, with the bottom cut off, sitting on top of the seedlings, like a mini greenhouse. The vinegar system would work the same, but would require repetitive mixing with new vinegar/soda, whenever a “burst” of CO2 was wanted.
If you don’t want to mess around with fermentation, you could always quickly generate CO2 with vinegar and baking soda (sodium bicarbonate).
14.3 grams of vinegar (5% acid) per gram of sodium bicarbonate should give a balanced reaction, with no waste of either material, generating CO2 whenever you need it.
I used a 1 liter batch of sugar and corn flakes and piped the gas into a 1liter bottle, with the bottom cut off, sitting on top of the seedlings, like a mini greenhouse. The vinegar system would work the same, but would require repetitive mixing with new vinegar/soda, whenever a “burst” of CO2 was wanted.
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