Run off ppm rising week 3 flowering. Even when giving them a feed strength they were fine on in wk2

What’s up everybody?
So I’m running 1800w hps over 5 plants in a capn style setup but 5 plants on one res not one plant per res. I had to go away for about 5 days and my brother took care of them for me but after about 2 or 3 days of me being gone the ppm runoff kept rising. I left him with a res mix at 850 and it stayed right around there the first few waterings. Then it started going up to 900 or 930 for couple waterings in a row. Had him mix a batch at 750ppm since they had been taking that at start of flower with no issues at all but even with that the ppm went up. So I had him do a little flush with a ppm mix of about 300 to try and clear out some built up nutrients. Following that he did a feed later with another 750 mix and ppm still went up.

Before I left I switched from half flower nutes half veg nutes (general hydroponics grow and bloom) to full flower nutes because they should have been pretty close to done stretchin which wasn’t the case. They were getting 2ml each per gallon and I switched it to 3 bloom 1 grow before I left. They continued growing another 4 inches atleast. Is it possible that they aren’t taking up all the flowering nutrients because they are still looking for more nitrogen. Causing the ppm to rise instead of drop?

I have just gotten back from my trip and am deciding what to do. Wondering if I should do a little flush and then start to work my way back up with the ppm slowly or what the best plan of attack is. I do have to do something soon as they need to be watered before I go to bed tonight and it’s already 10:40. But reguardless I am open to any suggestions for what you may do in my situation. If it’s not before I do it tonight I’d still love to here everything you guys think I should do so I can make any adjustments tomorrow and also just learn from the experience.

Thanks in advance

Always much appreciated

Plants really can't decide to take up one nutrient and not another, they simply uptake the solution that's available and rely on us to have the ratios correct for their needs. A plant can, however, choose to drink more water than ppm's. Anywho, how is your PH behaving? Are you doing a DWC setup, or ebb and flow or drain tables? Is your PH staying steady, dropping, rising?...Are the plants still drinking regular amounts of water, or have they slowed down their water uptake? We'll try to figure it out
*EDIT* Just saw the pic attatched, but still can't tell what kind of hydro system are ya are using lol.

Logan Burke said:

Plants really can't decide to take up one nutrient and not another, they simply uptake the solution that's available and rely on us to have the ratios correct for their needs. A plant can, however, choose to drink more water than ppm's. Anywho, how is your PH behaving? Are you doing a DWC setup, or ebb and flow or drain tables? Is your PH staying steady, dropping, rising?...Are the plants still drinking regular amounts of water, or have they slowed down their water uptake? We'll try to figure it out
*EDIT* Just saw the pic attatched, but still can't tell what kind of hydro system are ya are using lol.

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Thanks for the reply. So I have them in pots with mini Rockwool cubes basically. Top fed 15 minutes twice daily. Once at 9pm. 30 minutes after lights come on and I had them going again at about 5am. Lights go off at 830am. I did notice last night they didn’t get any run off for just over 2 minutes which is longer then usual so I was thinking the same thing. They have grown a lot and are taking up more water. So should I make the watering a little further apart? Like 9pm and 7am? Since they seem to be drying out a little between last watering of day and first watering.
Ph has been dropping bad. Never seen it go down so quickly. Only last couple days when I was gone though of course. Did a mini flush last night and the ph went down to 4.5. So ppm is going up an ph is dropping. It’s just odd cause the ppm I’m giving them they were doing good on before so it has to be the amount of water they are drinking.
Thanks again

Logan Burke said:

Plants really can't decide to take up one nutrient and not another, they simply uptake the solution that's available and rely on us to have the ratios correct for their needs. A plant can, however, choose to drink more water than ppm's. Anywho, how is your PH behaving? Are you doing a DWC setup, or ebb and flow or drain tables? Is your PH staying steady, dropping, rising?...Are the plants still drinking regular amounts of water, or have they slowed down their water uptake? We'll try to figure it out
*EDIT* Just saw the pic attatched, but still can't tell what kind of hydro system are ya are using lol.

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And it is a recirculating system. Using the general hydroponics lineup

TrichomeChaser said:

And it is a recirculating system

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i'd think that setup would work better drain to waste. have you ever tried it that way?

rkymtnman said:

i'd think that setup would work better drain to waste. have you ever tried it that way?

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What’s up man. I really appreciate you helping out. I never tried it drain to waste. I ran it this way last year with 2 plants and it was a super smooth run. But this time I been having all sorts of issues with my ph meter. Already bought and returned 3 of the groline ones that are like $79. They just keep losing calibration in a matter or minutes. My Bluelab guardian stopped working after a year so that’s in the mail going back for warranty as well. My only concern running it drain to waste is the amount of water and nutrients they will end up running through. The setup and feeding program is the same as the capn style setups. Bunch of info on his stuff online. Which he pulls great returns on by running one plant per res and feeding twice a day fifteen minutes each time and recirculates it. So I did that just on a bigger scale. I would do drain to waste but watering them for 15 minutes each time is supposed to keep the ph and ppm stable. And it has up until now for the most part. I would go thru a pretty crazy amount of water and especailly nutrients if I do drain to waste. With recirculating the 15gallon res lasts about 2-3 days. Drain to waste I’d end up going through the 15 gallon res daily if not more.

What kinda watering schedule would you recommend putting them on if I were to switch it over to a drain to waste setup?

Thanks again

wasn't trying to change your grow style and if it's worked in the past then keep on truckin'.

i do DTW but only go thru 15 gals about every 8 or 9 days.

my main guess as to why it's going up is that while you were gone, the rockwool dried up too much which concentrated the salts in the cubes and would lead to higher run-off.

i would think if you up your watering duration that should fix that problem. get some run off to make sure all the cubes are nice and wet.

rkymtnman said:

wasn't trying to change your grow style and if it's worked in the past then keep on truckin'.

i do DTW but only go thru 15 gals about every 8 or 9 days.

my main guess as to why it's going up is that while you were gone, the rockwool dried up too much which concentrated the salts in the cubes and would lead to higher run-off.

i would think if you up your watering duration that should fix that problem. get some run off to make sure all the cubes are nice and wet.

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Yeah I hear ya man. Last time went real smoothly. This round they are much bigger so may just be using more water. I get good run off every watering though. They run 15 minutes at a time so there is run off for 13 minutes atleast everytime. So I’m thinking that I need to make the second watering like an hour before lights go out. I had it setup to go on 3 hours before but as you said they are drying out too much between last watering and when lights come back on.

TrichomeChaser said:

Yeah I hear ya man. Last time went real smoothly. This round they are much bigger so may just be using more water. I get good run off every watering though. They run 15 minutes at a time so there is run off for 13 minutes atleast everytime. So I’m thinking that I need to make the second watering like an hour before lights go out. I had it setup to go on 3 hours before but as you said they are drying out too much between last watering and when lights come back on.

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you could even add one more feed halfway thru the dark cycle. probably much less time but enough to keep it moist thru the nite.

sounds like just a bit of tweaking will get you back in the zone again.

rkymtnman said:

you could even add one more feed halfway thru the dark cycle. probably much less time but enough to keep it moist thru the nite.

sounds like just a bit of tweaking will get you back in the zone again.

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I thought it was best to not water during lights but maybe I’ll give that a shot. What would you recommend doing for my next watering To try and get the ph and ppm to stable out? They were taking 750 ppm before with no problem

TrichomeChaser said:

I thought it was best to not water during lights

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just try to avoid the rockwool drying out too much. i've fed in coco during the dark cycle with no issues.

i would try to get the ppm dropping. pH staying stable or going up.

Okay so my lights are on 830pm to 830am. First watering is at 9pm. Second watering is at 530am. 15 minutes each. I’ll do another watering In the middle at 130pm during lights out. For say 5 minutes?

TrichomeChaser said:

Okay so my lights are on 830pm to 830am. First watering is at 9pm. Second watering is at 530am. 15 minutes each. I’ll do another watering In the middle at 130pm during lights out. For say 5 minutes?

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sounds like that should work. keep checking your runoff though. if its' still higher, then drop your feeding by a 100 or 200 ppm and see what happens.

rkymtnman said:

sounds like that should work. keep checking your runoff though. if its' still higher, then drop your feeding by a 100 or 200 ppm and see what happens.

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Yeah I always check run off and ph every single time. I just mixed up a small batch of 575 ppm. That way I can see what it does and mix a bigger batch if it drops like I should. It should go down because that’s not a strong mix at all for flowering so we’ll see what happens on it

rkymtnman said:

sounds like that should work. keep checking your runoff though. if its' still higher, then drop your feeding by a 100 or 200 ppm and see what happens.

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This shit got me stumped man. Watered tonight with around 575ppm and then run off went up to about 650. And even worse then that that the ph went from 6.0 going in and the run off went all the way down under 5. These plants are really testing my patience haha I’m thinking there must be some sort of salt buildup or something going on. Because it just doesn’t make any sense that a nute mix at 550ppm is too much for the girls. They were getting that well over a month ago. So I’m tryna think of what other things it could actually be. Not sure what else i can try.
Ppm going up and ph going down is usually a sign that the mix is too strong but I know that’s not the case because even the weak mix is getting a higher runoff.
That’s the only thing that is really coming to mind though. Buds are growing and the plants are still growing in height as well so it’s a tough one.
I’m thinking about doing a flush with just straight RO water and calmag to try and get the ppm down. Flush them until the run off gets really low and then follow that up with a 5 minute watering with a light nutrient mix so they don’t get shocked from being flushed of all the nutes.
That sounds like the best option in my head at the moment. Not sure what else I can really do because I’ve tried 750ppm and today did the 575 and the run off went up both times.
Hoping they didn’t get stressed into hermies somehow. Would they stop using as many nutrients if they were focusing on seeds?
Praying that’s not the case because they look pretty great right now. Tons of tops and stacked up but just trying to think of every possibility.
Thanks again man

i've never run in rockwool before so i'm not sure the best way to flush it would be. maybe try googling it and see what others say how to flush it?

yes flush,plants that size should have roots all over your tray??
Maybe its the RW holding too much,perhaps shorter feeds?
Not familiar with RW cubes,suggest hydroton next run.More forgiving.

I've never ran DTW or a recirculating system of the sort that you're using, but I will say that the cheap PH meters tend to be a money pit. I've had the most luck with the Bluelab PH and PPM combo monitor ( .https://www.amazon.com/gp/product/B003PD2N8Q/ref=oh_aui_search_asin_title?ie=UTF8&psc=1 ) Used it for a couple years, no replacing probes, just calibrate it once monthly. It's about 200$ off the bat, but not having to buy a brand new meter every few months saves you big time if you're intending on growing for long term.

rkymtnman said:

i've never run in rockwool before so i'm not sure the best way to flush it would be. maybe try googling it and see what others say how to flush it?

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Yeah something is up. I’ve flushed before with the Rockwool but even with a plain ro water flush the ppm runoff was 350 and the ph went down to 4.5. And that’s with no nutrients. So there has to be some real bad salt buildup maybe? I don’t know what else it could possibly be that’s causing the ph to drop and ppm to rise fast.

myke said:

yes flush,plants that size should have roots all over your tray??
Maybe its the RW holding too much,perhaps shorter feeds?
Not familiar with RW cubes,suggest hydroton next run.More forgiving.

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They have a lot of roots. They are in 5g pots I believe it is. So you think the Rockwool is holding too much and that’s causing the issues? Typically Rockwool is really hard to overwater like that and when I start the feed it takes 2 minutes before I get runoff. It’s just odd because they were taking 750ppm with no problems a week ago and now all of a sudden the ppm is going up no matter what strength I give it.

Logan Burke said:

I've never ran DTW or a recirculating system of the sort that you're using, but I will say that the cheap PH meters tend to be a money pit. I've had the most luck with the Bluelab PH and PPM combo monitor ( .https://www.amazon.com/gp/product/B003PD2N8Q/ref=oh_aui_search_asin_title?ie=UTF8&psc=1 ) Used it for a couple years, no replacing probes, just calibrate it once monthly. It's about 200$ off the bat, but not having to buy a brand new meter every few months saves you big time if you're intending on growing for long term.

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I agree 100%. I have a Bluelab gaurdian I bought last year. Spent the $250 thinking it would be great and I sent it back last week because it wouldn’t even turn on anymore. They are sending me a new tomorrow or Monday. That’s why I bought $79 groline one. Which still isn’t the really cheap ones but it failed me terribly so I’m Just hoping that blue lab will be here very soon.

I’m not sure but if you feel comfortable with a big flush like a lot I mean then that’s what I would do. Straight water just like rdwc for 12 hrs??