Hydro ph question

So the snippet from a ILGM article says the ideal ph for hydroponics is 5.5 - 5.8.

When growing hydroponically, the ideal pH is around 5.5 to 5.8. However, 5.3 to 6.5 is good, and 5.0 to 7.0 is acceptable. If you start to see numbers under 4.5 or higher than 8.0 you will begin to have nutrient absorption problems. If the pH reaches 3.5 or 9.0, there’s likely permanent damage to your roots.

Is this what all you hydro guy go by?

Seems like there could be a Cal-Mag issue. No?

Please excuse my ignorance.


Thats just optimum and you can only have 1 ph number, so you want it in the best range for everything. But usually your ph rises…at least thats been my experience. I start out at 5.8 and the next day they are usually between 6 & 6.1…some times i let them go to 6.3, but then i drop the ph back down. The swing is from the water to nutrient ratio changing as your plants take in water and nutrients at different rates and that climb actually helps them with uptake for nutrients in the higher range…so theres an ebb & flow to it.


Exactly…. pH in hydro’s optimum range is around 5.5-5.8. Thats the sweet spot so to say. Now some nutrients are more available in the higher numbers. Some in the lowers. So a bit of fluctuation between stages is welcome. But generally, staying in that targeted area, ur plant will have steady access to most things it needs.


Thanks yall

I have three plants on autopots. Just a week into 12/12 but pretty good sized girls.
This is one of them. From the side and top of Red

They go through about 3 - 4 liters a day. But I only mix enough for 2+ days - usually around 12 liters. f
I could mix more and fill the reservoir but choose not to because of PH drift. Like @ExoFly says, it goes up a little each day. I shoot for a mix of 5.8 and will go with 5.9. Then, about 48 hrs later I replenish with a fresh mix. They are in coco and being fed Jacks. I am using Jack’s 10-30-20 Blossom Booster the first couple weeks of light change.
I am thinking about using their 7-15-30 Finish the last couple of weeks. Anyone use it?
KootMed recommends a slightly narrower Hydro pH range of 5.8 to 6.1.


I did last grow and couldn’t keep the ph up. I tried for a week so I gave up and did a res change.

Keeping in mind every system is a little different. Pending on the amount of liquid may make it different.

I also use Jacks but I’ve found that near the end of grows the plant stops feeding on the nutes and is drinking more water, causing the ppm’s to rise witch in turn causes the ph to drop.
So if the ppm’s get over 1000 for me, that’s when the PH tends to drop. In that case I just add water, no ph adjustment, again what works for me may not be true for someone else due to water quality or whatever else may affect it.

During the normal grow including flower, if I set it on 950ish, and PH of 6.0 it will stay there up to near the end of the grow. Good luck @NYDon ! :+1:t2::v::sunglasses:

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What material are you using for the “net”? I used twine when I tried scrog and it was worthless. I built mine with PVC and screws like you’ve built yours.

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It is mason’s twine

It gives a little as opposed to the rigidness of dowels or bamboo. It makes correcting mistakes or repositioning stems a little easier.
Have you done PVC scrogs before?


I’ve done a couple of scrogs. I don’t do them any more. I switched to nylon twine too after the debacle with plain old twine. lol.


My runoff is consistently higher than that. The low is 1200 with it usually 1400 - 1600. Yesterday it was 1900, which surprised me. The runoff pH was still 5.9. They just finished 4th week of 12/12. I feed at 900 - 1100 and 5.8 or 5.9. I’ll have to watch. I don’t want the ppm to climb much more.
In my 1 gallon SOG which is near the end of flower the ph just dropped to 5.7 and ppm over 1900. I will back way off the next couple of times I feed them. Some of the fans are starting to show age and decline.


When they are in the tent I may drop a net on them but it is for support (wishful thinking). This is the first time using a scrog for its intended propose.


I used the finish but wasn’t impressed. The homoginazation wasn’t good. Its looks like its just part A and B mixed together. But with A being a powder and B little balls (calcium nitrate) I didn’t feel like I was getting consistent mix in just 2 grams. It’s actually sd to mix 100 gallons at once… I’m having better luck using a monopotasium phosphate fertilizer 0 52 34. Thats what I use to replace Jack’s Bloom which i wasn’t impressed with lol

This is from Nicky
Veg… 3.6g A/ 2.4g B /1.2g epsom

1st 2 weeks of veg… 2g A/2.7g B/ 2g mkp 1.2g epsom

Remainder of grow before flush. 3.8g A/2.6g B/1.8g ep.

The extra epsom helps allow high intensity light during flowering. You could also use 1.5g epsom during veg if you have a very bright light

I’ve seen others that use 2g A/2g B/2g mkp/1,.2g ep.

Mixing with mkp: A 1st, Epsom 2nd, B 3rd, mkp last then ph

Thanks for the great info. I was thinking of trying mpk instead of Jack’s Finish. I know Myfriendis410 uses / recommends it too. At this point in my learning Jack’s I decided to try Finish.
I tried upping Epsom during veg but it caused me problems. I read too much into coco needing calcium so I also supplemented with CalMag. My well water is high in calcium so the combo of upping Epsom along with CalMag really messed with uptake. So, I got rid of calmag, went with straight 321 ratios and have no more issues (fingers crossed).


Goin by that the range u want would be ph 6.0 sorry abit stoned at the moment the range u want is 6.0 goin by that chart

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