PH of nutrient mix question


#1

Is it normal for the PH of my nutrient mix to be around 5? I’ve been fighting to keep the soil around 6.5 and not had to add any nutrients yet. I mixed some today and checked the PH. I only added 2 cups to each plant, but even at that, I can imagine my PH eventually getting out of whack in the other direction.

Should I adjust the PH of the nutrient mix with something? I will be watching the plants to see what effect it has and will check the PH before the lights go out this evening.

Thanks guys.


#2

Yes it is normal for many nutrient mixes when mixed with pure water end up a little on the acidic side, say around 5 - 6 pH. You could add some tap water to bring it up or a “pH up” additive. Either way. You just want to be sure your root zone or run off is stabilizing where you want it.


#3

And I’ll share this link here as well as it seems very relevant to your situation.

http://edis.ifas.ufl.edu/ss165


#4

Not sure I understand. What is the starting PH of your water? In soil, we can add dolomitic lime to buffer the PH. But; It seems like you have a water PH issue to start with. I have never heard of any nutrients that would drop the solution PH to 5.0

I look forward to hearing back from you. Peace :slight_smile:


#5

The water I mixed the nutrients in was distilled with a PH of 7. (Tested prior to adding the nutes.) The Nutes I added were the basic week 5 from the Fox Farm soil feeding schedule. I was surprised is all. But I’m going to try to mix the same nutes next week with my tap water which runs closer to 7.9. If the PH goes down enough, I can at least save a buck a week on distilled water. :wink:


#6

Thanks for replying. Are you sure that your PH pen or meter is accurate? Are the leaves of the plant twisted?

I have experienced in the past bazaar PH readings when mt PH probe went out on me.


#7

Thanks for your help.

I’m never a hundred percent sure but the meter does read 7.0 on distilled water and 7.9 on my tap water. I bought a meter that only tests liquid and I believe it is way off. It shows 5.0 on distilled water and 9 on tap water. No curly leaves that I can find. I did have some issues when I was using my tap water without nutes that led me to believe the meter is pretty close. One thing I did notice, if the soil is dry, it always reads 7. If the soil is damp, I get varying readings at different locations either in the same pot or a different one.

I’m going to see about getting some test solutions so I can see how accurate everything is. Right now the girls seem to be happily sprouting buds all over the place. Hmm, perhaps I could test my saliva and see what my ph is. My mouth keeps watering every time I open the tent…


#8

Great news. I asked about the twisted leaves due to the fact that a PH imbalance will immediately show as twisted leaves.

You know Bro; Best way to check soil PH is the runoff. Right? What are you using to test PH? Sorry, if I missed this earlier.


#9

I’ve got a luster leaf dirt meter. Two prongs, polished up, stuck in the dirt. Cheap walmart version. I also have a YOPO autopen that needs to be recalibrated. Runoff is hard to check. I guess I should have trays under the pots to catch that. Right now it just goes to the floor of the tent and into a couple of towels I change every time they get wet.


#10

There is nothing wrong with the old dirt meter. However; I would advise you to spend 50 bucks and get a Milwaukee PH51. You will ger a packet of PH solution, and it comes in a case with a lil screwdriver to calibrate the pen. Be sure to buy storage solution to go with it. PH probes can go bad within a year or so, if you do not store them correctly in solution. trust me. Always take care of your meter probes. Solution is a lot cheaper than pens or meter probes.

Peace.lw


#11

I just added the PH55 to my Christmas list. (it seems the PH51 is retired.) Thanks, you’re the best.


#12

All the way down to 5.0 seems a little much but I don’t think it’s impossible with distilled water.

I have 150PPM 7.5pH kinda hard tap water, after mixing my nutes, it settles to 6.5pH all on its own.

Yes, a cheap soil probe needs the soil moist to work, in dry soil it will read not much different than in the dry air. Also you should get different readings depending on where you stick it in. You want to take a reading from the lower 2/3rds of the pot, where most of the roots are to get the most accurate reading, the soil will not read the same pH where there are not many roots, and the pH of the root zone is what we are really interested in.


#13

You will be happy with that Milwaukee PH pen :slight_smile:


#14

Another thought on the way you make your distilled water with a distilling machine, if I’m not mistaken, this is likely to make things slightly acidic anyway. Evaporating to distill your water, as it re-condenses, some very mild acids may be made, this will move the pH downward slightly. In the distilling process, distilled water actively absorbs carbon dioxide from the air, making it acidic, as some carbonic acid is made. This should be a very mild affect but it could still be a contributor.


#15

That makes sense. I mixed the same amount of everything in a gallon of tap water today and it went from 7.8 to 6.9. I sprinkled some sulphur on top of the soil before I poured the mix on. A couple of hours later I checked the plants and the range is nearly perfect.

I’m confident I won’t have ph problems in the future.

Two weeks in flower and the buds are starting to look delicious. I’ve put my wife on guard duty in front of the tent with her shotgun so I won’t get any crazy ideas.

:wink:


#16

Nice! lol


#17

Good to hear that you solved the issue.


#18

I am adjusting the pH of my water before I add nutrients. I checked the nutrients before adding to the plants and it had gone up. It was 6.5 after adjustment before nutrients and 6.9 after 24 hours of adding the nutrients. Should I adjust the pH again before watering or let it go? Or alternatively, should I shoot for a lower number before adding nutrients, say, 6.0 before adding nutrients. I am not sure how to proceed. My nutes are: Ca/Mg 3ml, fish fertilizer (5-1-1) 5ml, micro (5-0-1) 7ml, deuce-Deuce (0-0-22) 2ml, Humboldt honey 3ml, all in one gallon of water.

I am just starting flowering, day 2, and do not want to have problems with the solution during flowering. I am growing 2 WW and one AK-47.

Thanks for your help.


#19

I don’t adjust PH until after nutes and directly before adding to the plants. It’s the only way I’ve been able to keep on top of PH. I also gave up on the adding sulfur to the soil. Now I mix nutes, PH the solution, adjust the PH, pour.


#20

Yup, add nutes, stir really good, maybe even let it sit for 15 minutes or more, then check pH, then finally adjust pH to desired level.

Some nutes are designed to bring pH neutral, 7, water, down to 6.5ish, and so they will bring your pH down, some are designed to be added to tap water which usually averages around 7.5-8.0, and bring them down to 6.5ish. These will bring neutral water with low ec/ppm, down maybe even lower.

Some nutrients might bring the pH up,

So it is always best to adjust your pH after everything has mixed and settled.