Hi, growers! I have a problem with PH. Before watering ph is 6.0 after watering ph=8.1. How to stabilize PH? To correct ph I use phosphoric acid.Plant grows in coco. 2 months from seed. Early-flowering stage. Indoor. Photoperiod. The problems began when I changed length of the day from vegetation to flowering stage. Accordingly change the plan of nutrition. Starting give the NPK for early-flowering stage.
Well you should transition to flower feed when buds start form. Not before that. A lot of people think oh im in flower and need to use those nutrients. Each strain can be different an may not be ready for the nutrients. And you can flush the plant with R/o water until you have the correct ph. Question? Did you stop using the veg nutrients and go to flower only nutrients? Sometime you need to add the grow nutrients and the flower nutrients and slowly take them off veggie nutrients over a week. Its like giving the plant its regular food and then you switch it all a sudden and the plant doesn’t like it.
I add complex nutrients which includes 3 components: A(N/P/K=5/0/0), B(0/4/3) and C(0/0/3,5) On vegetation stage I added on 15% nutrients less than on early flowering (this was recommendation of the producer of the nutrients ). I gave plant around 600-800ppm on veg and on flower increased ppm till 1000. On 42 day of veg I change length of the day. All these 42 days IN ppm was around 600-800, ph was 5.8-5.9. OUT 500-700 ppm, ph=7.6. After 42 day within 2 weeks IN ppm ~1000 ph=6.0 OUT 800ppm ph=8.0-8.2. on 56 day IN 1000ppm, ph=6.0 out 1040ppm ph=8.3. Is the R/o water mean reversal osmosis water?! Is it means that I water the plant with the same solute which I receive in OUT liquid? in OUT liquid I have ph=8.1 and if I water with ph=8.1. How does it change the situation ? If I am wrong please correct me.
Im assuming you are watering with plenty of runoff everytime you feed. I also have the ph climb slowly but adjust for it as time goes on.
How much runoff are you getting? Im mainly in leca ebb and flow but when I see my res start to climb in ph I’ll try to drop the PH to the lower part of the acceptable ph range like 5.8
OK…first a couple questions for you to help us understand…
- You did a GREAT job checking your in/out ppm and pH.
- Are you using R/O water for irrigation?
- It sounds like your nutrients are not well buffered. When you mix up your nutrient solution adjust the pH to where you want it. NOW PUT that nutrient solution aside for 12 hours and check the pH AGAIN…did it drift on you ?? If it DID, now carefully measure how much pH DOWN you have to add to your original nutrient solution to get it back where you want it…
NEXT time you mix your nutrients…put all the pH Down in it to start with! That will give you a good starting point !
All your advises are great. Thank you for feedback. But I still don’t understand how to fix the problem. It’s seems more complicated. I want to talk about cation-anion balance and how nutrients impact on ph balance. Do anybody have knowledge about this?
@katerina, with all due respect, you have a pH issue that needs immediate attention.
If you want to understand ‘cation/anion balance’ and nutrient effects on pH…you require a basic class in Qualitative Inorganic Chemistry. Our nutrients (whether organic or inorganic) are all the same molecules, and all are chemical ‘salts’ (as in IONIC).
Wish you only the best of luck !