PPM - Let's go higher or let's keep it low

[DRM Ranch]

I'm feeding very low PPM in veg, the plants are trucking along with no real issues that I've been unable to deal with, however I'm wondering how to tell if going higher or lower on the nutrients would be a good idea.

I'm sure trial and error would work over time, but I'm looking for some more concrete signs.

Ideas, wisdom, anything.

Thanks all

 

[Papageno]

The res measurements tell you everything you need to know.

The short answer is if the PPMs are dropping and the water is dropping you need to up the nutes.

If the water is dropping and the PPMs are stable you are perfect!

If the water is dropping and the PPMs are going up you have a problem start topping of with just pH'd water.

All of that is assuming your pH is stable and not going crazy.


Now if the pH is dropping fast you may have a real problem OR you may just need to up the nutes. If it is doing so and the PPM is stable and there is no water uptake you need to flush. In fact if there is no water uptake then there is a problem in general (assuming we are not talking about very small plants). If the water is dropping and the pH is dropping then you may need to up the nutes.

It takes a bit of learning here but if you keep the PPMs right (and some other things) then the pH should maintain a stable decent range.


Check out this guys journal. He has it all working without adjusting the pH. Just monitor and top off with the right levels and all is good.

ClosetCase420's - RDWC - 600W MH/HPS - Wonder Woman - Grow Journal - 2015

 

[Castor27]

The res measurements tell you everything you need to know.

The short answer is if the PPMs are dropping and the water is dropping you need to up the nutes.

If the water is dropping and the PPMs are stable you are perfect!

If the water is dropping and the PPMs are going up you have a problem start topping of with just pH'd water.

All of that is assuming your pH is stable and not going crazy.


Now if the pH is dropping fast you may have a real problem OR you may just need to up the nutes. If it is doing so and the PPM is stable and there is no water uptake you need to flush. In fact if there is no water uptake then there is a problem in general (assuming we are not talking about very small plants). If the water is dropping and the pH is dropping then you may need to up the nutes.

It takes a bit of learning here but if you keep the PPMs right (and some other things) then the pH should maintain a stable decent range.


Check out this guys journal. He has it all working without adjusting the pH. Just monitor and top off with the right levels and all is good.

ClosetCase420's - RDWC - 600W MH/HPS - Wonder Woman - Grow Journal - 2015

Villiageidiot hit it on the head great advice here. the only thing I'd add is be carefull if you adding any veg booster. if you add too much the nitrogen in it can cause the ph to drop crazy fast. I made this mistake and after a week of pulling my hair out trying to stableise the solution I stubbed upon a post talking about nitrogen and how company's use it to stabilize nutriant solutions. basically the way it was explained was there is 2 kinds of nitrogen used in hydro nutriants one is readily available to the plants and the other must be broken down in the system before becoming available to the plants.

if it is too much of the one that has to be broken down your solution will become unstable and drop rapidly. I'm talking super fast I was dropping 1 to 2 full points overnight. just something to be aware of.

 

[DRM Ranch]

The res measurements tell you everything you need to know.

The short answer is if the PPMs are dropping and the water is dropping you need to up the nutes.

If the water is dropping and the PPMs are stable you are perfect!

If the water is dropping and the PPMs are going up you have a problem start topping of with just pH'd water.

All of that is assuming your pH is stable and not going crazy.


Now if the pH is dropping fast you may have a real problem OR you may just need to up the nutes. If it is doing so and the PPM is stable and there is no water uptake you need to flush. In fact if there is no water uptake then there is a problem in general (assuming we are not talking about very small plants). If the water is dropping and the pH is dropping then you may need to up the nutes.

It takes a bit of learning here but if you keep the PPMs right (and some other things) then the pH should maintain a stable decent range.


Check out this guys journal. He has it all working without adjusting the pH. Just monitor and top off with the right levels and all is good.

ClosetCase420's - RDWC - 600W MH/HPS - Wonder Woman - Grow Journal - 2015

I'm in the H2O level and PPMs are dropping, I keep my pH at 5.8-5.9 but it falls by a few points between waterings.

I'll up the PPMs, but how much?

My PPM at mixing is in the 520s and falls to the 420s after 5 waterings, I correct pH daily when I water.

 

[DRM Ranch]

Villiageidiot hit it on the head great advice here. the only thing I'd add is be carefull if you adding any veg booster. if you add too much the nitrogen in it can cause the ph to drop crazy fast. I made this mistake and after a week of pulling my hair out trying to stableise the solution I stubbed upon a post talking about nitrogen and how company's use it to stabilize nutriant solutions. basically the way it was explained was there is 2 kinds of nitrogen used in hydro nutriants one is readily available to the plants and the other must be broken down in the system before becoming available to the plants.

if it is too much of the one that has to be broken down your solution will become unstable and drop rapidly. I'm talking super fast I was dropping 1 to 2 full points overnight. just something to be aware of.

I'm mixing 5ml ProTekt (first), 10ml Grow, 2ml MagPro, into 2.5gal RO water at 24ppm.

I cut my clones Oct22, they are in grodan cubes (croutons), in #3, #5, and #7 pots with the exception of one slacker that's in a #1 pot. The #1&3 plants were slow to root in clone, I never culled the smaller plants because this is my first go it alone grow and I wanted to hedge my odds at getting a good harvest if I lost plants.

Thanks for the advice.

 

[Castor27]

this is my first time as well and I don't try and push them nore have I been able to keep a stable ph until recently. my plants look amazing and are growing rapidly. I am unfamiliar with any other nutriant line than what I use. I'm running mills nutriants and it's a part a part b kind of formula with 3 boosters.

the best advice I could give you is if they look healthy and happy! your probably on the rite track! wish I could see your girls!

 

[Castor27]

just curious how are you growing currantly? also what is the ppm of your solution?

 

[DRM Ranch]

just curious how are you growing currantly? also what is the ppm of your solution?

520PPM at the time I mix the nutrients, I'm growing them under 864watts of t-5 lights.

Here are the roots on one of the girls at my last transplant.

 

[Castor27]

my goodness what a beautifull girl. I find root pics even betr than plant pics. I'm no pro but I'd say don't do anything. why change what is obviously working well?

 

[Papageno]

I am telling you go read that journal. I am hold his hand through the grow and I explain everything.


There is a lot to know. I even explain some complicated stuff there that takes a while to type.


You don't want to be using pH UP or DOWN to stabilize the res. You want to let it naturally drift within the good zone and use a good nute solution to keep the pH happy. I can go over a month just topping off my res and monitoring the PPM and the pH stays happy. If I really worked hard I could go longer. I have a friend who does on the nose 8 week grows and never changes his res.

Trying to keep a tight pH range is bad for the plant. you can make it work by over dosing and under dosing stuff to compensate but there is no prefect spot. For some things especially if you have a deficiency you may actually want to run it up to 6.4 or even higher for Calcium.

All that said I run a living res so it is a lot easier. If you are running sterile it all applies it is just harder to do. I just saved a guys grow who was running sterile by converting him to my tea and he will never go back. He had a pithyum problem that he could not get rid of after trying everything. 1 day in my tea and everything is cleaned up and his plants are taking off.

The best part is when he started posting he was truly afraid of it ...now he swears by it...

What's the difference between a sterile rez and a beneficial rez?

Undercurrent RDWC With Compost Tea Grow - First Journal

 

[Castor27]

I agree 100% I'm running orca for bennies plants seem to love it. I'll check out the journals mentioned!

 

[Papageno]

I will say this up front and hopefully you do some research (or go through closet cases journal where I explain the whys and such)...


Following a recipe is a recipe for failure. Unless they are running your exact system, same ventilation and lighting bla bla...Unless you have the same level of photosynthesis going on then the nute levels are just relative. The nutes are not food. they support photosynthesis. If you have more fan leaves you need more nutes and that is why as they get bigger we need to add more nutes. That is also why as they get near the end we stop giving nutes. So because one person runs at 500 means that is what there plants need for their age / maturity and size and the RH of the room and the temps and the PAR levels.... If you have a room that has better conditions and you are doing more photosynthesis you can handle more nutes. if you have worse conditions you can't handle as much.

This is why you have to learn about what PPM actually means as far as day to day readings and water levels. the plants are talking to you and they will tell you exactly what they need. That is the beauty of Hydro. If you know what you are doing it is so easy and cool to feed them just exactly what they need. In soil if you do it right it can get kinda boring because you basically just add water and at some point change the light schedule. I mean there is a bit more to it then that but it is not so responsive and spot on. You actually water it like once a week and feed it a home brew tea every 2 or 3 weeks depending on maturity (maybe even less). But since you really don't do anything for a week you kinda have to nail it. In hydro you can fix things daily...but you can't screw it up for long or the thing crashes. In soil you can make a mess of it for a long time and recover it in a day...it wont look recovered for a while but you can fix almost anything wrong in the soil in a day. Soil is great for beginners because you can really make a mess of things and still get to the finish line. In hydro I have seen people screw up about 3 days which caused stunting late in bloom which caused the whole grow to go hermi...because of a 3 day misstep.

 

[DRM Ranch]

 

[DRM Ranch]

Nutes in at 804 PPM, runoff and reservoir stabilized at 540 PPM, pH dropped from 6.0 as mixed to 5.9.

 

[DRM Ranch]

Today I mixed up nutrients to 575 ppm and landed on 6.0 pH, hand watered with drain water filling the reservoir.

pH out read as low as 5.3, this tells me the range over the last 24 hours was between 6.0 and 5.3. My opinion is that the spread is fine but it is shifted to low. My next water/feeding will go in at 6.2-6.5 likely the higher figure taking into consideration the draining water is a blend of fresh 6.0 and remaining lower pH nutrients in the media.

I will slightly increase the PPM to 600 as well, mainly looking to see how it effects pH spread as it seems the 800 ppm did not help that.

 

[Papageno]

Well actually I was hoping we would see that. With the pH dropping like that it would lead me to be inclined that the nutes are too low. In a good healthy system if the nutes are too low the pH will start dropping. I explained why fairly deep in the journal I posted for you. If you haven't gotten there I will try to find time to explain again but I am real busy right now and going out of town and will be offline for a while starting tomorrow.

I think you are doing the right thing learning about the PPM and pH relationship.

 

[DRM Ranch]

Well actually I was hoping we would see that. With the pH dropping like that it would lead me to be inclined that the nutes are too low. In a good healthy system if the nutes are too low the pH will start dropping. I explained why fairly deep in the journal I posted for you. If you haven't gotten there I will try to find time to explain again but I am real busy right now and going out of town and will be offline for a while starting tomorrow.

I think you are doing the right thing learning about the PPM and pH relationship.

I am trying to learn the relationship between pH and PPM, what frustrates me so much is being reactive rather than proactive.

Since my last post here I've added a dehumidifier to help me control humidity spikes upwards of 90% while my lights were off, this resulted in a very clear increase in nutrient uptake, perhaps better said as increased transportation. That's a good thing.

As well I adjusted the nutrient mixture ratios resulting in a moderate increase in the initial PPM reading and a 6.3-6.4pH without pH adjustment.

At this point the PPM is increasing 20 PPM post watering but prior to being topped off with RO. The pH is lowering several tenths with the initial runoff being in the mid 5's and stabilizing back up to high 5's.

In an effort to understand this better I'd like to seek a bit more refined answer to a point I spoke to earlier; I will try to be clear but please forgive any obvious ignorance.

If the pH in is 6.5 and the pH out is 5.5, can I assume the media pH was 4.2 at the time of watering? My logic is as follows; n= nutrient in, r= runoff, m= media (6.5n+4.2m)/2=5.5r.

The numbers are of course just imaginary, the concept is what I'm looking at right now.

Further into my thought process is this; if the final runoff and reservoir after 15 minutes is stabilized at 6.5pH I assume the media is at 6.5pH at that very moment. From that point forward the pH is at the whim of how much water and nutrients are taken up by the plant, falling or elevating. How much drift occurs is dependant on how long between waterings.

Now, if my very basic assumption on media pH is correct to any extent my question becomes this. Do I base any adjustments on the lowest calculated media pH, or the stabilized pH of the nutrient solution after it has changed?

My hypothesis is that I should base any adjustments on the calculated pH in an effort to keep the media within a range of 5.5-6.5.

I hesitate to formulate the nutrients at higher than 6.5pH but my logic seems to lead me to this if for nothing more than to see what might happen.

Growth seems to remain explosive as is so I'm not exactly in trouble here. I'm constantly looking for ways to refine and learn.

 

[Papageno]

Well I think it is not so simple as that but you are not far off.

If the pH in is 6.5 and the pH out is 5.5, can I assume the media pH was 4.2 at the time of watering? My logic is as follows; n= nutrient in, r= runoff, m= media (6.5n+4.2m)/2=5.5r.

There are many factors impacting the quality of this including how clean was the drip pan you pulled the runoff from. Preferably you have a a system where it goes back to the res and is taken care of there but I think not.

What you can say if in theory everything is clean and honest that yes the medium was well below 5.5 but by how much is hard to tell. You have to deal with the issue of dilution. maybe you had 1 gallon of water in there and added 4 gallons of water. so that would mean in those number substantially less than 5.5 as a little bit of water brought it down that far. If for example (just making a point) you added 1 gallon to 200 gallons and half a gallon came out that was at 5.5 then you could say the whole res was at about 5.5 because what you added was inconsequential.

So in general run off is an indicator but not guaranteed to be easily correlated to specific values.

Further into my thought process is this; if the final runoff and reservoir after 15 minutes is stabilized at 6.5pH I assume the media is at 6.5pH at that very moment. From that point forward the pH is at the whim of how much water and nutrients are taken up by the plant, falling or elevating. How much drift occurs is dependent on how long between waterings.

So I still need to understand better your setup. are you a single external res running flood and drain or some sort of recirculating DWC?

It is expected and natural for the pH to go up and down naturally as the plant is selectively taking up nutes. That said there is no golden standard. If you read the journal I posted for you he just went through this and proved that even deep in bloom that at 6.3 it will take up Phos and Pot very easily and fast if it wants. The plants do not like quick changes. They adapt to the situation they are in. As long as we are in the good range all is good then we do not adjust a thing. My boy Closet Case has his girls drinking up a few gallons a day of Phos and Pot nutes in bloom now up like I said around 6.3 because that is where the plants want to be. He keeps topping off with 5.8 and they stabilize right back at 6.3 and suck it up. The plants are causing it to go there and wont let him do anything about it naturally and they are happy. He could dump acid in the res which is a very bad way to solve this nonissue and get it there and shock the plants and cause an imbalance and then need to dump the res.

Trying to stick at 5.8 is based on a basic misunderstanding how how the res works. Companies like AN worked real hard to make stuff to fit that market so people who don't care to understand horticulture and hydroponics can be successful. But that is just making it easy for people who don't care.

You in fact care. I would recommend googling to fond hydroponic websites that are non cannabis because all the principals are the same. understanding the basics goes a long way to understand the refined version you are trying. Look at big corporate hydroponic vegetable gardens and see what they are doing and how it works. Look up veg only plants like Lettuce and see how that differs from fruiting plants like tomatoes and it will all be much clearer.


To answer directly... the roots come into a balance with the res. The concentration of nutes in the roots match what is in the res up to a point. Some nutes are more mobile than others and depending on if there is an overdose building up or not and how big the fan leaves are there may not be much space fro some stuff. these are the things that are hard to overdose. Some things like Nitrogen are easy to overdose. So as it transpires and gets the nutes pushed up it mat start to get out of balanced with the res. Maybe there is more Nitrogen in the roots % wise then the res because Phos is packed and not moving but nitrogen is being sucked up. so now the roots are sitting in solution and not the correct balance and start leaching back the Phos to try and get balanced. it can't help but try to be balanced...it doesn't make decisions about this it just happens like a towel in water make no decision how much to absorb.

Alright so like you that was all just an example but the point is... the plant will adjust the res accidentally as it takes up stuff and needs others. In a healthy disease free res the pH will drift around as the roots are doing their thing. I can go easily over a moth just topping off and letting it ride without making any adjustments. My buddy does fast 8-12 week grows and doesn't change it at all.

Now, if my very basic assumption on media pH is correct to any extent my question becomes this. Do I base any adjustments on the lowest calculated media pH, or the stabilized pH of the nutrient solution after it has changed?

Again I need to understand the solution path both delivery and recovery. I will post a chart below that shows in general the pH trend over the grow. it shows that during Veg you run it like lettuce and in bloom lower down for more Phos uptake but again that is not really needed if the plant is happy to take it at 6.3. I run DWC so it is real easy. If it is in the good zone you don't touch it and top off with between 5.8 and 6.0 and you are good to go. in either case if you have like flood and drain then just make sure the res is in the good range and if not adjust it slowly back to the edge and then even slower back down to the middle . If you do this slow enough the roots will walk with you and help keep it there...all of this assuming yo have a healthy res.

My hypothesis is that I should base any adjustments on the calculated pH in an effort to keep the media within a range of 5.5-6.5.

I hesitate to formulate the nutrients at higher than 6.5pH but my logic seems to lead me to this if for nothing more than to see what might happen.

No...don't top off with stuff out of range. Don't top off with stuff drastically different. Slowly bring it in line and then keep it in line. If it doesn't' walk with you then there is a problem and you need to exchange the res.

But yes in your example you would be in a locked out state so you should start with dumping the res. Then starting a fresh res. Some might even do a 24 hour flush with like Clearex then start a new res.

 

[Papageno]

 

[DRM Ranch]

I'll do a flush with very low ppm pH'd water. I don't have clearex in my hands to use, seems like apple juice looking at the ingredients LOL.

Laughs aside, I'm running 10 gallon (actual fill volume) reservoirs under each plant, pump location is on the reservoir floor, nutrients are delivered by hydro halo.