pH going DOWN issue. Yellowing Leaves. .

[smoke headies]

Same thing happened to my last crop.. I have no idea what is going on.

I'm using 3x3 ebb and tables... hydroton.. watering every 4 hours...

plants are 100% fine until week 3 or 4.. then they start yellowing (not a nute issue) buds look healthy, but leaves start developing a yellowness to them.. it fucked up the last crop and I got almost half the yield I usually get.. I nought all brand new nuts. (Im using floranova, and thats is.... and yes im shaking it like a bitch before i mix it in)


Now my pH is going DOWN and not UP over several waterings.. why is this?

 

[Carl Carlson]

Not to sound like an ass, but you thought of everything that might seem obvious?

such as pH meter calibration or do you use test strips?

It sounds like the plant roots are uptaking some water, but not nutrients.

I wonder if it is something environmental, re: transpiration related. I noticed that you started another thread about dark period ventilation.

 

[bendoslendo]

I run DWC and constantly battle pH dropping. H2O2 seems to be the only thing that helps. I use it at about 1mL/gallon (30%h2o2) every 3-4 days.

What are your rez temps?

 

[smoke headies]

Carl: My pH meters and PPM meteres are all calibrated almost weekly. I have a feeling they are sucking up h20 and not nutes as well... always happens at week three of flower recently... i dont know why... I really dont know if its transpiration related or not. how can i test?

bendoslendo: Im not running DWC, but does h202 help with ur dwc??? i may add some in my nute rez.....

 

[johnny123]

hey,sounds exactly like whats been happening to me.i think i have it under control now(after 3 or 4 runs with the same problems).i've decided it was due to a salt build up in the root zone.i now flush through with plain ph'd water about 2-3 weeks into bloom.that seems to have sorted it for me,hope it helps ya!

 

[BurmeseDragon]

So many people take over watering as a lack of nutrients or a low PH, if it's a low PH they burn more than they yellow!

Watering ever 4 hours doesn't sound that frequent, sounds like not enough at all...maybe it's drying out. I modified ebb and flow to run constantly and just drilled holes to run up some air stones...works well if the other kinks get out!

 

[bendoslendo]

Yeah I know your E&F. I just noticed in your post though that the pH drops over several waterings. If it were a root rot issue, the drop would likely occur very fast. Yeah H2O2 is the only thing I have found that works for me.

 

[smoke headies]

johnny123: what type of nutes were u using?

bend: check ur pms!

 

[smoke headies]

Update: I'm currently flushing with clearex... I'm thinking this may be the problem.... they need a FLUSHING!!!

How often do you guys flush in ebb and flows???

 

[El Toker]

Dropping pH always means pythium for me. It tends to happen during the summer when I run the lights at night. I figured that it was because the tubs (DWC 20 Litres) stayed warm all day.

If it is pythium the root ball will look a dirty yellow colour rather than white. The plants will tend to die from the bottom up, "Pythoff" or H202 controls it well.

I changed the light cycle so that temps dropped to 14C or under at night giving the reservoir the chance to cool off and this seemed to get rid of the problem.

 

[TalkingMonkey]

I had the same problem when i tried floranova...stopped using it and problems disapeared. I now use flora micro and flora bloom.

 

[smoke headies]

Currently looking in to see if Flora Nova is the problem.. not flushing.... or MG def...

 

[bendoslendo]

If your pH is falling below 5 regularly you definitely have a MG deficiency. MG amongst others. Fixing your pH will allow these nutrients to be used.

Not shaking the Flora Nova vigorously enough may cause your pH problems as well.

 

[smoke headies]

bendo: I guess i should have stated that i wasnt getting INSANE pH drop.. it was more like 5.9... then i'd check it the next day and it'd be 5.7...

I agree with SHAKING FLORA NOVA!!!! I stopped buying the gallons because its literally IMPOSSIBLE to mix that shit properly... i buy the litres..

 

[high road]

good indication of feeding too much to start with.. Flush, then back off of your nute strength and see if it helps. There are a lot of things that can cause these symptoms, that's why you are seeing so many different pieces of advice. The only way is to systematically remove each variable to see what makes a difference for you.

It could be pythium....could be over feeding, could be mg deficiency, could be a number of things.

In my experience...when the ph drops consistently each day, it is a direct result of too much food/ or to much transpiration.

Good luck in your process...

 

[johnnyla]

dropping PH means salt build up and the resulting acidity. flush your plants till the PH is where you want it, wait a day, and resume feeding.

i fucked up and ignored PH for a few feedings and only looked at PPM and saw my PH go below 6.0 with similiar leaf symptoms.

 

[smoke headies]

Update: Just finished flushing for a full day (got a good 3 - 4 hour flush). Put in a new nute batch, pH is at 5.8... used 300 ml flora nova.. PPMs are at 800 (.5 scale) = 1.6 EC.

I'm hoping it was a SALT BUILD UP.. the only thing that worries me is that when i checked the flush solutions PPMS, it was under 100ppm..... my plants DO look better after the 1 day flush though... hopefully they'll spring back...

 

[smoke headies]

 

[bendoslendo]

Yeah 5.9->5.7 over one day doesn't sound like the rot I've encountered. Mine will go 5.8->4.4 in 1 day if I don't use H2O2, such a headache.

It sounds like it was salt buildup? Let us know how things turn out and good growing bro

 

[highonmt]

smoke,

Are you using ro water? If you are the floranova series ph's very low like 4.4 at 1.8ec. I have seen this same thing, pH dropping with fnb I think it might be a result of not totally dissolving the fulvic acid or something. I tried just mixing 5gal of ro and fnb in a bucket with an air stone and letting it sit overnight, the same thing happened. How are you mixing your nutes? does your pH continue to drop after the first few days?
Cheers,
HM