FUNDAMENTALS OF RDWC

Darth Vapour

Darth Vapour

Well-Known Member
firsttimeARE said:
I meant nutrient strength. I hear you can run hotter mixes in UC.

Thinking if making the move myself.
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Once you get it dialed in water temps ph etc you are laughing to harvest as for strength of nutrients its strain dependent i have never exceeded 2.3 EC or 1150 ppm that is my turning point how i been doing it is slowly raising strength 3/4 way through bloom i start decreasing strength so start 450 - 500 clone 1 EC up to 2.3 then back down to 1.3 - 1.5 chop day
rez change 7 - 10 days system flush / re sterilize chlorine added ,, My new build will consist of UV water sterilizers
 
Deepwater600ppm

Deepwater600ppm

Member
Darth Vapour said:
Vapor pressure deficit.....
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, 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. 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.
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Fuck, that is a new world opened up to me I was unaware of.
If I'm straight up honest, I've never even given humidity much of a glance these past few go's. Since rdwc, I haven't even checked.

It'll take me a few reads to fully understand VPD but principle seems sound, and a good link between canopy temp and humidity. So what do you aim for in regards to top canopy temp and humidity?
 
Deepwater600ppm

Deepwater600ppm

Member
Darth Vapour said:
Once you get it dialed in water temps ph etc you are laughing to harvest as for strength of nutrients its strain dependent i have never exceeded 2.3 EC or 1150 ppm that is my turning point how i been doing it is slowly raising strength 3/4 way through bloom i start decreasing strength so start 450 - 500 clone 1 EC up to 2.3 then back down to 1.3 - 1.5 chop day
rez change 7 - 10 days system flush / re sterilize chlorine added ,, My new build will consist of UV water sterilizers
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im around day 30, after yesterday's res change I set ppm at 700. 500 of base (canna Aqua) then some custom pk-type boost to take it to 700. For the method I am trying to stick to (hht) this is too much. What you saying about that?
 
Deepwater600ppm

Deepwater600ppm

Member
Mini update...
- Changed res, it takes no time at all now I have it locked down.
- Cleared out under canopy as much as I dare. When you have the amount of branches I do, being comfortable defoliating is essential. In the past few weeks, I have removed about 4 buckets full of plant, maybe more. If I had of known they were going to get so big, I would have trained better. This was meant to be a 'learning hydro' practice grow, I was anticipating fucking it up.
That's it for flower room really. I'll have another deleaf this week I'm sure but for the best part, they are on their own.

Makes me glad I have the two veg'ers to play with. Both doing pretty well, I don't want them to get massive so not really paying attention to a perfect environment. I'm a bit worried they will get too big. Still about 6 weeks till they get flipped so the more abuse the better. SD branches are pretty much not breakable by hand, its so strong and tough. I could do with a couple of big bends but might have to ease them into position rather than break.

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I know its a mess.
 
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Darth Vapour

Darth Vapour

Well-Known Member
Well only you can really judge what the plants can take ,,, Read your plants needs, just remember higher room temps = more plant transpiration there fore prior lets say you put 700 ppm of feed in 3 - 4 days later you top up check ppm level,
if it reads 300ppm then you know plants took up 400 ppm ,, re mix 400 to equal it back to 700 and so on but remember if lots of volume is lost then plants are transpiring to much ,, back off nutes and give it the water ,,
Cause your really throwing away your nutrients find the happy equilibrium

But you in there 650 - 750 1.3 - 1.5 just remember 15 - 30 percent less veg time required
As for training plants,, Least from my experience its i always used to start pretty early problem is starting to early is stem height to foilage and wasted foilage that you eventually clean up due to less light penetration,, Sucker buds draining actual bud production possible mold n mildew etc
i found starting week 2 - and still training up to 2 weeks on 12/12 ( Stretch phase ) ( super cropping ) non stop as well cleaning under canopy and constantly cleaning them sucker buds that wll keep trying to come back

looking good keep it up
 
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