PH question

[Cobzilla]

I am on my second crop using ebb and flow hydro.. My PH remains fairly stable through vegging but it seems that the later in the flowering process (week 6 now) my PH begins to drop rapidly from one day to the next and I am have to adjust my PH almost daily.. why is it that PH fluctuations occur far more frequently later in flowering? am I missing something I should be doing.. still learning the hydro way.. grew for years in soil with no issues.. I must say I love hydro and should have switched a long time ago.

 

[Streetpro09]

What nutrients are you using?

 

[Zaphod420]

I am on my second crop using ebb and flow hydro.. My PH remains fairly stable through vegging but it seems that the later in the flowering process (week 6 now) my PH begins to drop rapidly from one day to the next and I am have to adjust my PH almost daily.. why is it that PH fluctuations occur far more frequently later in flowering? am I missing something I should be doing.. still learning the hydro way.. grew for years in soil with no issues.. I must say I love hydro and should have switched a long time ago.

Salute Cobzilla, here are a couple really helpful "hydro" slides if you haven't seen them before.
Couple follow up questions:
What PPM/EC are your currently at?
What strain are you running and around what week should it normally finish?

 

[Cobzilla]

Thanks Zap those charts are awesome... I am currently growing some Purple Larry which has a 70 to 80 day flowering period... I just started my 6th week of flower.. PPM is between 500-600 and I have never used EC as a barometer, just PPM. and im using Flora series 3 part nutrients.. thanks for all the replies.

 

[Zaphod420]

Thanks Zap those charts are awesome... I am currently growing some Purple Larry which has a 70 to 80 day flowering period... I just started my 6th week of flower.. PPM is between 500-600 and I have never used EC as a barometer, just PPM. and im using Flora series 3 part nutrients.. thanks for all the replies.

Hmmmm... so I just looked up a feed chart for flora nova 4(didn't see a Flora 3 part chart) and I would say you are running a little lean on the PPM for the start of wk 6. I would go with their Medium Feed suggestion of 600-750 unless they are crushing it then I have no problem going aggressive 750-900. Hope this helps and try to get them dialed in asap so nothing gets locked out and they can finish strong.

 

[Cobzilla]

I use this feeding chart.. the medium feed schedule

 

[Zaphod420]

I use this feeding chart.. the medium feed schedule

Oh right on... If your plant(s) look healthy(rootball to) then I would try bumping them to 800 PPM and see if that stops the ph from crashing on you so badly. A lot of times I find most plants are real potassium hogs towards the end of flower.

 

[Streetpro09]

I use the same nutes but only the purple and pink. Equal parts in veg. 1part purple to 2 parts pink in early flower and 1 part purple to 3 parts pink late flower.

My recommendation to you is add more pink. I've experienced the same ph dive toward the end of flower. Adding more pink seemed to stabilize the system.

 

[Streetpro09]

How offen do you change water/nutes in your rez?

 

[Cobzilla]

i change water once a week but i also have to add 5 gallons of water a day so i try to use appropriate amounts of nutes to compensate for the water addition. my rez is 25 gallons and i use this system here with 4 pots, not 6. appreciate the tips pro, i will try it.


AirCube Active Oxygen Ebb and Flow Grow System

 

[Streetpro09]

Sweet system! Raising ppm like zaph said might just do the trick too. Maybe a bloom booster like this might help with your current nutrient schedule.
Just start adding it in at the 5th week to raise ppm that extra bit. Each strain seams to finish a little different. Indica leaning tend to feed heavy and then need more later in flower. Sativa leaning tend to be lighter more consistent feeders. Just an observation after watching ppms and ph a time or two.