What Causes Ph to Drop?

[polishfalcon420]

well I have a reaccuring issue with my crops. what I have going on is once I hit the 5th week of flower my my ph starts to drop and I mean when I start out with a fresh batch of nutes the first 3 or 4 days it rises like normal then all of the sudden it will drop like a point to a point and a half overnight. I grow in a recirculating DWC setup. this happens consistantly between several different strains that I have grown and always happens right around the fourth to fifth week of flower and continues till harvest. I have tried adding plain water with topoffs and have also tried adding nutes with topoff to maintain ppm's. I recently setup a friend of mine with the same setup and bam fifth week flower hes got the same issue. I have never had any rootrot or disease that I can tell, plenty of air supplied to each bucket and res. plants are very healthy overall. I am wondering if this is caused by the plants draining a certain nute out of the solution causing the ph to become unstable. I read some stuff about ph rising due to the fact that the plants are eating the nitrogen and thus naturally causing ph to rise would the consumption of something else cause it to drop naturally? like I said I am using dwc and running GH's floranova line with the floralicious plus and koolbloom. I quit using the floralicious plus early in flower. I have used it all the way through the grow before and have had the same issue. if someone could shed some light on this issue I would greatly appreciate it.

 

[mr.smileyface]

Could be your plants are using calcium more in hydro. Try adding a bit of calmag.
Plants use water faster than nutes causing the ph to drop and ppms go up. You might have to add more water or a couple drops of ph up.

 

[polishfalcon420]

that has crossed my mind. the plants usually use pretty close to an equal amount of nutes and water as the ppm usually drops. if the ppm's do rise its not by very much maybe 50ppm. right now my trainwrecks are drinking about 2-2.5g a day and maintaining a 1400ppm solution pretty well except for the ph thing after 3 or 4 days of it gradually rising and adjusting to get it back down to 5.5-5.8 all the sudden it crashes.when this happens if its not below 5 then I just add none adjusted solution with topoff and it will get it back up around 5.7 but the next day it usually dives below 5. up to this point I have always drained my nutes and started with a fresh batch but changing the solution every 4 days just seems like a waste and a pita sometimes. my common sense tells me that either the plants are draining the solution of a certain element or they are putting something back into it like nitrogen that would cause ph to drop vs the opposite of what it does when it drains it causing the ph to rise.

 

[sparkafire]

I just went though that a while back and when I flushed and backed off the nutes it stopped. I don't know if it was something else but it did stop it 1400 seems high try the flushing and back off the nutes and see if it works. You have nothing left to lose but your PH dropping.

 

[polishfalcon420]

Ive done that a few times and it never worked with other crops. right now they just finished up their 5th week and the one is about 5ft tall and over 12ft circumference with buds about half the size of a 20oz bottle. there is also no signs of nute burn at all.

 

[hellraizer30]

Ph can go down dew to beneficials die off

 

[maps84]

that has crossed my mind. the plants usually use pretty close to an equal amount of nutes and water as the ppm usually drops. if the ppm's do rise its not by very much maybe 50ppm. right now my trainwrecks are drinking about 2-2.5g a day and maintaining a 1400ppm solution pretty well except for the ph thing after 3 or 4 days of it gradually rising and adjusting to get it back down to 5.5-5.8 all the sudden it crashes.when this happens if its not below 5 then I just add none adjusted solution with topoff and it will get it back up around 5.7 but the next day it usually dives below 5. up to this point I have always drained my nutes and started with a fresh batch but changing the solution every 4 days just seems like a waste and a pita sometimes. my common sense tells me that either the plants are draining the solution of a certain element or they are putting something back into it like nitrogen that would cause ph to drop vs the opposite of what it does when it drains it causing the ph to rise.

Hey man! In that case PH downs usually because the plant is over fed and in the way to toxicity of one or several mobile elements. This happens because it already has all the nutrients it needs to grow and given the solution is too hot, the plant is being forced to take more water than nutes causing unbalance in the reservoir further resulting in unstable PH levels and worst. You should try dropping some ppm until you find the sweet spot for your current strain.

 

[polishfalcon420]

I get what you guys are saying about being overfed but the plants are eating more nutes than they are using water right now. with this crop even at 1400 they are drinking that much water and using more nutes than each gallon they are drinking. for example yesterday morning the ppm was 1450 I dded two and a half gallons of water mixed at 1400ppm. this morning they drank 2.5g since yesterday and ppm's were down to 1350. meaning they drank 2.5 gallons at 1400 and took an additional 100ppm from each gallon remaining or you could say they dranks 2.5g at 1600 or so. oh yeah the setup is 2 plants each in a 3.5g bucket with a 3.5g res in recirculating dwc. each bucket has airstones. also this morning my ph didnt drop which is the first time Ive had that happen in this kind of situation, usually once it dives it will continue to due so until I change out the solution. so Ill see what happens here.

 

[polishfalcon420]

Ph can go down dew to beneficials die off

I totally understand that and agree but I just dont see whats going on to cause that situation if that is the cause.

 

[hellraizer30]

Well im not a expert on bennys but i think if they dont have food they will die, as with all organic
Living creatures. Im shure someone will chime in here with what that food is

 

[My420]

well I have a reaccuring issue with my crops. what I have going on is once I hit the 5th week of flower my my ph starts to drop and I mean when I start out with a fresh batch of nutes the first 3 or 4 days it rises like normal then all of the sudden it will drop like a point to a point and a half overnight. I grow in a recirculating DWC setup. this happens consistantly between several different strains that I have grown and always happens right around the fourth to fifth week of flower and continues till harvest. I have tried adding plain water with topoffs and have also tried adding nutes with topoff to maintain ppm's. I recently setup a friend of mine with the same setup and bam fifth week flower hes got the same issue. I have never had any rootrot or disease that I can tell, plenty of air supplied to each bucket and res. plants are very healthy overall. I am wondering if this is caused by the plants draining a certain nute out of the solution causing the ph to become unstable. I read some stuff about ph rising due to the fact that the plants are eating the nitrogen and thus naturally causing ph to rise would the consumption of something else cause it to drop naturally? like I said I am using dwc and running GH's floranova line with the floralicious plus and koolbloom. I quit using the floralicious plus early in flower. I have used it all the way through the grow before and have had the same issue. if someone could shed some light on this issue I would greatly appreciate it.

No you are ok. It is natural for the PH to rise usually untill about week 4-5 in flowering then the PH starts to drop. Nothing to worry about that means that everything is ok. Just stay on top of your PH and dont let it get out of line. I have to adjust mine to raise it every time in that stage of flowering.

 

[My420]

Hey man! In that case PH downs usually because the plant is over fed and in the way to toxicity of one or several mobile elements. This happens because it already has all the nutrients it needs to grow and given the solution is too hot, the plant is being forced to take more water than nutes causing unbalance in the reservoir further resulting in unstable PH levels and worst. You should try dropping some ppm until you find the sweet spot for your current strain.

I am sorry but that statement is not true......... Ask any Botanist. If that were the case the PPM would not be dropping. My PPM drop with my PH. Your statement is way off sorry to say. This is natural for a hydro set up from what I have seen and have no signs at all of burn ( which is what happens when the plant is over fed ) If you are over feeding them you would be experiencing some type of burn weather it be the leaves turning or the tips burning. Your plants do not have a "filtration system" in there roots to only uptake water without taking the nutes in them. The plants will uptake what is in the water that is why they will burn. You can even overfeed them to the point that they literati burn up to a crisp and if your statement is true then your saying basically that they have an auto defense to over feeding? Sorry no. If you are over feeding you will see signs of burn. No burn means your not over feeding them. The signs are vary obvious to. Now Nute lock is something different and a whole other post.

 

[My420]

YEAY!! Someone that talks facts and not " I work in a hydro store or my mom showed me this trick" + rep

Thank goodness someone that thinks like me. I do not want to hear what your friends brothers uncle's grandpa did one time. If it worked for you show me proof if you did not grow it then you have no idea if that story is true and if it really did work no matter what someone tells you because mostly people LIE THERE ASS OFF to make themselves look better instead of saying wow I did bad what can I do to get better. That is the difference between a good grower always trying to improve and get better and a horrible grower who is to stubborn to change his ways because his ego will not let him ask for help thus never getting better and never getting a REAL quality yield.

 

[sparkafire]

I agree its the little guys growing one or 2 plants that get hurt when bad info is regurgitated from Johnny Weed Baron who really just wants to have a nice plant but gets advice like use urine to raise PH levels (I have seen it )
Growing is not easy or inexpensive and cheap or organic solutions are in my opinion are the root of all the bullshit on here.To be honest most new growers WAY over think it and end up frantically looking for help ( how many time do you see HELP!! my plants are dieing) in the Plant problem area? Only to see a bunch of guys put in there 2 cents that you can see that are going to make matters worse.
The best part is when they call you out to be a bad ass and find themselves buired in science. When I first started I had not one clue how to grow but I bet I have 300 hrs researching this and the different ways of growing and then researching what experienced growers say on the boards to double cross reference their input and then make my decision. Hell right now I am researching plant tissue sampling to maximize nute schedules. Not to say I am better but i will tell you I will research the Fuck out of something before I make any changes to my grow and people just wont spend the time to do that.

Sorry I just realized I was on a rant.

 

[My420]

I agree its the little guys growing one or 2 plants that get hurt when bad info is regurgitated from Johnny Weed Baron who really just wants to have a nice plant but gets advice like use urine to raise PH levels (I have seen it )
Growing is not easy or inexpensive and cheap or organic solutions are in my opinion are the root of all the bullshit on here.To be honest most new growers WAY over think it and end up frantically looking for help ( how many time do you see HELP!! my plants are dieing) in the Plant problem area? Only to see a bunch of guys put in there 2 cents that you can see that are going to make matters worse.
The best part is when they call you out to be a bad ass and find themselves buired in science. When I first started I had not one clue how to grow but I bet I have 300 hrs researching this and the different ways of growing and then researching what experienced growers say on the boards to double cross reference their input and then make my decision. Hell right now I am researching plant tissue sampling to maximize nute schedules. Not to say I am better but i will tell you I will research the Fuck out of something before I make any changes to my grow and people just wont spend the time to do that.

Sorry I just realized I was on a rant.

It is cool. I took Botany so first thing I did is research plant cell structure. Helped me a lot. I never would have thought to use Nitrozyme in combo with a few other things as a Foliar feed without the facts that I found researching.

 

[mr.smileyface]

Im thinking you should back off the nitrogen around week 5. That could be the problem. Like you said your self maybe the nitrogen isnt getting absorbs as fast as the other nutrients. If its acidic and not being used up it will cause your ph level to drop even if your ppm is the same. You said it yourself.

 

[My420]

Im thinking you should back off the nitrogen around week 5. That could be the problem. Like you said your self maybe the nitrogen isnt getting absorbs as fast as the other nutrients. If its acidic and not being used up it will cause your ph level to drop even if your ppm is the same. You said it yourself.

I stopped using Nitrozyme in beginning of week 2 and replaced it with Hydroplex but nitrozyme is actually a 0-4-4 mix that has Phosphate or P2O5 and soluble Potash or K2O and is derived from seaweed. It is just a algae extract. 2 week of veg and 1 of flower used superthrive, nitrzyme and wet betty, weeks 2, 3 and 4. Dropped the Nitrzyme and replaced with Hydroplex, Week 5 added purple max to the mix and left others the same. Week six starts Saturday that is a new mix for Foliar and rez water also. I will drop grow and max out on KoolBloom.

 

[mr.smileyface]

I use koolbloom dry at half strenght only. Im not a huge fan of additives as i got better results with just base. I do include some additives like voodoo juice, b52 , Karboboost and koolbloom dry.
I havent heard of the nitrozyme or hydroplex.
I just use a 1-1-1 ratio in the early weeks

 

[polishfalcon420]

Im thinking you should back off the nitrogen around week 5. That could be the problem. Like you said your self maybe the nitrogen isnt getting absorbs as fast as the other nutrients. If its acidic and not being used up it will cause your ph level to drop even if your ppm is the same. You said it yourself.

I agree but I just cant see where I am using that much nitrogen in the first place myself. last mix was 10ml floranova bloom and 7ml koolbloom per gallon. the nova is a 4 8 7 npk value and the koolbloom is 0 10 10 that put me at about 1450ppm. it does look like the larger plant may have a very small calmag def if at all but it does have red petioles and fan leave stems starting on the larger main branches. Im not to sure if that goes with the strain or not. I upped the koolbloom last res change due to this and have not really noticed much of a difference and its budding like crazy. there both actually very healthy plants but Ive just been trying to figure out more on the ph dropping cause Ive had it happen in all of my successful grows so far and in a couple that didnt go so well. successful meaning 2 lsd plants under 1000w net 27oz dried 2 northern light pure gold crosses of mine 29oz dries bud there was a couple others like a lemon skunk and a querkle together under a 1000w lemon skunk hit 15oz and the querkle hit 10oz. but on the other hand Ive had 2 bubba kush under oe light and only hit 12oz total between the two but they were kinda messed up from the start and could never figure them out. so most of the time I achieve pretty good results. this ph thing is just kinda getting to me maybe it is just the norm in my setup as is why my buddies is doing the same thing. I just keep reading all over that a healthy hydro setup the ph should rise.

 

[maps84]

I am sorry but that statement is not true......... Ask any Botanist. If that were the case the PPM would not be dropping. My PPM drop with my PH. Your statement is way off sorry to say. This is natural for a hydro set up from what I have seen and have no signs at all of burn ( which is what happens when the plant is over fed ) If you are over feeding them you would be experiencing some type of burn weather it be the leaves turning or the tips burning. Your plants do not have a "filtration system" in there roots to only uptake water without taking the nutes in them. The plants will uptake what is in the water that is why they will burn. You can even overfeed them to the point that they literati burn up to a crisp and if your statement is true then your saying basically that they have an auto defense to over feeding? Sorry no. If you are over feeding you will see signs of burn. No burn means your not over feeding them. The signs are vary obvious to. Now Nute lock is something different and a whole other post.

Sorry I wasn't clear enough. And yes they have defenses for even that! what I meant was that If the nute component absorbed are more akaline than acidic the solution PH will go down and vice versa, as the nutrient salts gets more concentrated within the solution in unbalanced ratios.

PH rises because most elements require a slightly lower PH than 6 to be available. There are only 2 elements that need a higher pH which are Mg and P. Both are required enormously by MJ plants but not nearly as much as N and K which both lower the PH. So your plants should eat the N and K, rising PH slightly as the more alkaline elements will still be present in the solution so the opposite is true. In hydro when I see constant PH lowering is usually because bad bacterial growth or Salt build up in the root zones.