louis_last
Member
I noticed that there is a very old thread from 2014 which raised this issue and the concensus seemed to be that it made no difference and/or wasn't worth the effort as the 400ppm of atmospheric co2 is more than adequate for emersed growth. That thread quickly devolved into a debate about global warming which isn't my intention so I wanted to start another to report that after some experimentation I have found it makes a huge difference - at least when growing various mosses emersed on lava rock. I can't comment on vascular plants but it's certainly the case that co2 supplementation is routinely employed in the commercial growth of various vascular plants including cannabis and I strongly suspect that many aquarium plants would also benefit in emersed setups.
I think something people may overlook is the fact that to sustain appropriate humidity levels in emersed setups we are often reducing air exchange to an extent that could potentially lead to co2 depletion particularly when longer photperiods are deployed to speed up growth. I certainly was anyway. I've also read that some plants at least can exploit up to 1600ppm CO2.
I'm growing various mosses and liverworts on lava rock in an emersed setup where the rocks sit on flat pieces of slate supported just above the water level in the bottom of the container that is maintained at around 5cm. This allows me to use of an ultrasonic fogger to maintain near enough 100% humidity and distribute nutrients to the moss. Previously the top was sealed with clingfilm and the only air exchange came when I peeled back the cling in order to closely inspect the moss and I began wondering whether the system might benefit from co2 supplementation.
I rigged up an inexpensive diy system using 250g of sugar dissolved in 350ml of water with one sachet of gelatin which I allowed to sit in a 2L bottle until it had set and then added 1L of water with a teaspoon of dried yeast before running an airline through a tight fitting hole in the side of my emersed setup. At night I just pull the air line out of the hole to interrupt the co2 supply when I turn the light off and, being so small, the hole doesn't lead to a problematic drop in humidity overnight and allows for a little extra oxygen to enter the growth chamber during the hours of darkness. The system introduces between 1 bubble every 8 seconds and 1 bubble every 18 seconds as ambient temperatures in the room fluctuate.
The results have been fantastic and within a couple of days I noticed a real increase in growth. It's obviously hard to quantify but the improvement is pretty unambiguous. I did consider that my moss and liverwort rocks which have all been started using material finely chopped with scissors (blender is way too destructive just fyi and leads to an excess of dead matter that encourages bacteria and fungi) could have just been maturing to a stage where their growth visibly accelerated anyway but I rule this out on the basis that the rocks are all home to different species, that were chopped up and introduced at different points, and a real noticeable improvement is evident in all of them. It could be the case that a lower ph of the water is responsible for the improvement but it seems more reasonable to assume that the concentration of co2 is the real culprit. Unfortunately I have no way of knowing what levels in ppm I'm achieving with this method or at what rate it's being converted into oxygen in the growth chamber but I just thought someone might be interested to know that it definitely does seem to produce appreciably faster growth - at least in these more primitive plant species. Interestingly the species of springtail that I include in the setup to help prevent mold and algae seems unaffected by the extra co2 where I had expected it to kill them which I suppose might support the notion that the moss is able to effectively exploit the higher concentrations and is producing sufficient oxygen to prevent co2 accumulating to fatal levels.
I imagine these plants might struggle more with a sudden transition to submerged growth so I would plan to discontinue the co2 at least a week before submerging them.
I hope this information might be useful to anyone trying to multiply slower growing species of moss and liverwort faster for larger or more moss intensive aquascapes I'd be really interested to know if anyone else has experimented with co2 supplementation for emersed setups or during the dry start method since 2014 and had positive or negative results.
I think something people may overlook is the fact that to sustain appropriate humidity levels in emersed setups we are often reducing air exchange to an extent that could potentially lead to co2 depletion particularly when longer photperiods are deployed to speed up growth. I certainly was anyway. I've also read that some plants at least can exploit up to 1600ppm CO2.
I'm growing various mosses and liverworts on lava rock in an emersed setup where the rocks sit on flat pieces of slate supported just above the water level in the bottom of the container that is maintained at around 5cm. This allows me to use of an ultrasonic fogger to maintain near enough 100% humidity and distribute nutrients to the moss. Previously the top was sealed with clingfilm and the only air exchange came when I peeled back the cling in order to closely inspect the moss and I began wondering whether the system might benefit from co2 supplementation.
I rigged up an inexpensive diy system using 250g of sugar dissolved in 350ml of water with one sachet of gelatin which I allowed to sit in a 2L bottle until it had set and then added 1L of water with a teaspoon of dried yeast before running an airline through a tight fitting hole in the side of my emersed setup. At night I just pull the air line out of the hole to interrupt the co2 supply when I turn the light off and, being so small, the hole doesn't lead to a problematic drop in humidity overnight and allows for a little extra oxygen to enter the growth chamber during the hours of darkness. The system introduces between 1 bubble every 8 seconds and 1 bubble every 18 seconds as ambient temperatures in the room fluctuate.
The results have been fantastic and within a couple of days I noticed a real increase in growth. It's obviously hard to quantify but the improvement is pretty unambiguous. I did consider that my moss and liverwort rocks which have all been started using material finely chopped with scissors (blender is way too destructive just fyi and leads to an excess of dead matter that encourages bacteria and fungi) could have just been maturing to a stage where their growth visibly accelerated anyway but I rule this out on the basis that the rocks are all home to different species, that were chopped up and introduced at different points, and a real noticeable improvement is evident in all of them. It could be the case that a lower ph of the water is responsible for the improvement but it seems more reasonable to assume that the concentration of co2 is the real culprit. Unfortunately I have no way of knowing what levels in ppm I'm achieving with this method or at what rate it's being converted into oxygen in the growth chamber but I just thought someone might be interested to know that it definitely does seem to produce appreciably faster growth - at least in these more primitive plant species. Interestingly the species of springtail that I include in the setup to help prevent mold and algae seems unaffected by the extra co2 where I had expected it to kill them which I suppose might support the notion that the moss is able to effectively exploit the higher concentrations and is producing sufficient oxygen to prevent co2 accumulating to fatal levels.
I imagine these plants might struggle more with a sudden transition to submerged growth so I would plan to discontinue the co2 at least a week before submerging them.
I hope this information might be useful to anyone trying to multiply slower growing species of moss and liverwort faster for larger or more moss intensive aquascapes I'd be really interested to know if anyone else has experimented with co2 supplementation for emersed setups or during the dry start method since 2014 and had positive or negative results.
