cobshopgrow
Well-Known Member
there are probably other knobs also, but hang your light higher when you think theyre stressed isnt a bad move.
LED and Calmag issues.
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Keesje
Well-Known Member
Some root rots do occur more easily at higher temperatures. That is right. But the reason they do, is because warmer temperatures are better for most organsisms. The whole metabolism just works better with slightly higher temperatures. Both of your cannabis and your root rot 
But root rot comes in many ways and is never triggered by higher temperatures by itself. Also swings in EC can help trigger it. The quality of your water. Hygienic aspects. There are many growers who have water of 25 degrees and never had root rot.
The difference between DO is water of 17.5 C / 63 F and water of 20 C / 68 F is probably around 0.7 mg per liter (9.9 mg instead of 9.2)
That is a small difference, but even then... the difference is irrelevant because of atmospheric pressure that will 'refill' the maximum amount of O2 in your rez or tote all the time.
Metabolism in water of 20 degrees however works better then in water of 17.5.
Most of the papers I read are in Dutch. Wageningen University is the world's leading university on agriculture and their library is impressive.
Besides that, in the Netherlands agriculture is a huge industry. The Netherlands is the 2nd biggest exporter of agriculture (US is nr. 1, but has a population that is almost 20 times of that of the Netherlands). In the Netherlands we don't grow a lot of corn and grains (not a lot of space for that) but we grow a lot in huge complexes of greenhouses.
Anyway, all these growers also have their own institutes where they do research and experiments. They are a very useful source of information.
Edit: added Fahrenheit as well
But root rot comes in many ways and is never triggered by higher temperatures by itself. Also swings in EC can help trigger it. The quality of your water. Hygienic aspects. There are many growers who have water of 25 degrees and never had root rot.
The difference between DO is water of 17.5 C / 63 F and water of 20 C / 68 F is probably around 0.7 mg per liter (9.9 mg instead of 9.2)
That is a small difference, but even then... the difference is irrelevant because of atmospheric pressure that will 'refill' the maximum amount of O2 in your rez or tote all the time.
Metabolism in water of 20 degrees however works better then in water of 17.5.
Most of the papers I read are in Dutch. Wageningen University is the world's leading university on agriculture and their library is impressive.
Besides that, in the Netherlands agriculture is a huge industry. The Netherlands is the 2nd biggest exporter of agriculture (US is nr. 1, but has a population that is almost 20 times of that of the Netherlands). In the Netherlands we don't grow a lot of corn and grains (not a lot of space for that) but we grow a lot in huge complexes of greenhouses.
Anyway, all these growers also have their own institutes where they do research and experiments. They are a very useful source of information.
Edit: added Fahrenheit as well
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Impregnant
Active Member
Yea i just plugged the chiller because this is my first RDWC run, and of course you read a ton of bullshit before to start...but i will do it different next time.Some root rots do occur more easily at higher temperatures. That is right. But the reason they do, is because warmer temperatures are better for most plants. The whole metabolism just works better with slightly higher temperatures. Both of your cannabis and your root rot
But root rot comes in many ways and is never triggered by higher temperatures by itself. Also swings in EC can help trigger it. The quality of your water. Hygienic aspects. There are many growers who have water of 25 degrees and never had root rot.
The difference between DO is water of 17.5 degrees and water of 20 degrees is probably around 0.7 mg per liter (9.8 mg instead of 9.2)
That is a small difference, but even then... the difference is irrelevant because of atmospheric pressure that will 'refill' the maximum amount of O2 in your rez or tote all the time.
Metabolism in water of 20 degrees however works better then in water of 17.5.
Most of the papers I read are in Dutch. Wageningen University is the world's leading university on agriculture and their library is impressive.
Besides that, in the Netherlands agriculture is a huge industry. The Netherlands is the 2nd biggest exporter of agriculture (US is nr. 1, but has a population that is almost 20 times of that of the Netherlands). In the Netherlands we don't grow a lot of corn and grains (not a lot of space for that) but we grow a lot in huge complexes of greenhouses.
Anyway, all these growers also have their own institutes where they do research and experiments. They are a very useful source of information.
I have some cutting which are plants right now, because i dont have time for them. Water temperature is room temperature. Roots are perfect.
I think i will do my next run with higher water temperature and microbes teas. Because im used to compost tea with soils, and i like it. Ive read about running sterile or running microbes. Both looks interesting. But i have a personal preference for life vs death.
Anyway.... that is not the first time that i have problems with leds, and distance between leds and plants. I will not be very surprised if all that mystery could be related to that again.
My tap water is spring water. It is 30ppm straight out of the tap. Mainly SiO2 in it for pipes i think. Almost 0 Calcium and magnesium in it. They put 0.04mg/L of CL2 in it. I put it straight into my system. I was putting air stones in it for 24h in the past. I dont do it anymore. So working with this water is almost working with RO water. I was working with RO water at the begining. I quited, found myself ridiculous wasting 100L of water for 100L of RO water, removing 30ppm of SiO2. It resolved many PH problems by the way for veg. Now im facing PH dropping issues since i switched to 12/12, but i feel that all is related somewhere. Calcium deficiency, Led, ph dropping. Seems pretty close when you know that calcium and magnesium are buffering PH.
Tetrahedral
Well-Known Member
Some root rots do occur more easily at higher temperatures. That is right. But the reason they do, is because warmer temperatures are better for most plants. The whole metabolism just works better with slightly higher temperatures. Both of your cannabis and your root rot
But root rot comes in many ways and is never triggered by higher temperatures by itself. Also swings in EC can help trigger it. The quality of your water. Hygienic aspects. There are many growers who have water of 25 degrees and never had root rot.
The difference between DO is water of 17.5 degrees and water of 20 degrees is probably around 0.7 mg per liter (9.9 mg instead of 9.2)
That is a small difference, but even then... the difference is irrelevant because of atmospheric pressure that will 'refill' the maximum amount of O2 in your rez or tote all the time.
Metabolism in water of 20 degrees however works better then in water of 17.5.
Most of the papers I read are in Dutch. Wageningen University is the world's leading university on agriculture and their library is impressive.
Besides that, in the Netherlands agriculture is a huge industry. The Netherlands is the 2nd biggest exporter of agriculture (US is nr. 1, but has a population that is almost 20 times of that of the Netherlands). In the Netherlands we don't grow a lot of corn and grains (not a lot of space for that) but we grow a lot in huge complexes of greenhouses.
Anyway, all these growers also have their own institutes where they do research and experiments. They are a very useful source of information.
Hydro would be more productive at higher root temperatures?
Impregnant
Active Member
I think that it is an establish fact that plant's metabolism increase while water temperature increase. Also for microbes. Goods and bads.
Keesje
Well-Known Member
Not only in hydro.
Look up 'root temperature' and 'yield' and you will come across many scientific papers about it.
Of course don't overdo it with temperature. There is a certain range and there is an optimal temperature for every plant and every strain.
For lettuce and tomatoes the ideal root temperature is around 77 F / 25 C (according to Cornell University).
That is in soil but a plant's metabolism and DNA structure do not suddenly change because they are in hydro.
Tetrahedral
Well-Known Member
Yes my seeds germinate a lot quicker when placed in a warm location,
Is there a higher temp system for hydro as so far most are sub 20c.
twentyeight.threefive
Well-Known Member
If you are trying to pinpoint a CalMag issue on VPD or the fact that they are under LEDs then I think you may be looking at the wrong root cause. Plants are completely capable of extremely healthy with terrible VPD.
Tetrahedral
Well-Known Member
Those vpd charts don't seem to represent the conditions it grows in out in wild, I couldn't follow their sense.
Keesje
Well-Known Member
I don't get what you mean by this.
Could you explain a bit more?
VPD in 'the wild' has a wide range. Cannabis can grow in so many climates.
Even when you follow it back to it's roots, you will see that it originated in different climates.
For me all the talk about uptake of nutes and such, is way above my head.
But I read on many forums that people have issues with Calmag after they switched to led. And many claim it has to do with the lower leaf temperature under led. And leaf temperature is an important number for VPD.
Impregnant
Active Member
Ok,
First thing that i can say is that my 4-5°C difference between room and leafs is caused by a too cloose Quantuum Board. I just moved the LEDs up, and problem was solved. I am now in the 2-1°C range. Everything has changed from that point. EC and PH acting the opposite way they have done for weeks now.
I'm at 1.4 VPD which is almost ideal. Plants drinks a lotttttttt. Have to lower my EC now i think. Now that they are acting normally, i will let you know about Calcium and Magnesium hunger.
I have just ordered a tool that will help me to measure my Photons density over my area. This way, i will find the perfect distance between my plants and my lights. That is the second time that i have problems of distances between Quantuum boards and plants.
First thing that i can say is that my 4-5°C difference between room and leafs is caused by a too cloose Quantuum Board. I just moved the LEDs up, and problem was solved. I am now in the 2-1°C range. Everything has changed from that point. EC and PH acting the opposite way they have done for weeks now.
I'm at 1.4 VPD which is almost ideal. Plants drinks a lotttttttt. Have to lower my EC now i think. Now that they are acting normally, i will let you know about Calcium and Magnesium hunger.
I have just ordered a tool that will help me to measure my Photons density over my area. This way, i will find the perfect distance between my plants and my lights. That is the second time that i have problems of distances between Quantuum boards and plants.
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twentyeight.threefive
Well-Known Member
I don’t understand the concern with VPD or LED though, unless it's just for education. Did you used to grow with HPS or something else and now are noticing CalMag issues?
Second time with the same lights running the same strain? Every variable is going to make each grow a little different.
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Impregnant
Active Member
Same light too close. It just my fault. When you come from HID lights, you kinda think that you can go closer with LED because they run much cooler.
Tetrahedral
Well-Known Member
As far as I can tell perfect Res temps hang around 20, Seems counterproductive not to run Res at 25c, lost yeild.
So the VPD charts aren't for us, they might work but don't educate, ours would have a much wider central line that show the ability to handle the wider variation. A slight difference between indica and sativa shown in seperate charts. It's all a bit weak and confusing, how about something that works better?
Impregnant
Active Member
Just try it. You will see how much happier are your plants when you tune your VPD.
Tetrahedral
Well-Known Member
Tune my VPD to an arbitrary chart on Google search or tune it to real marijuana growth parameters? I'm tuned to cannabis already I'm not changing to your vpd chart though.
Keesje
Well-Known Member
Again, I don't get you.
You say that you think that perfect temperature is 20.
But you also say that is counterproductive not to run at 25?
If you have a suggestion what works better.
VPD numbers are used all over the world by commercial growers.
The only thing is: Who came up for the numbers for cannabis?
Impregnant
Active Member
Whatever the numbers. VPD is just a way to make the transpiration goes up or down and to observe results. Specially with such fast responding plants.
I love how people try to make it worthless, while they want to feed theirs plants the more they can.
I love how people try to make it worthless, while they want to feed theirs plants the more they can.
Tetrahedral
Well-Known Member
No I'm just querying why most run lower than the perfect temp, don't worry I'll read some threads work it out.
When I see some saying to tune vpd and others growing much better outside that range then it's obvious they aren't for cannabis, certainly not the flowering period in warm countries. So if someone tells me to tune my VPD I'll assume they are just saying what charts recommend and not giving any specific info on cannabis growing, lame on a 420 site but I'm sure better info exists in some threads I'll just have to dig a little deeper for that.
Thanks