Help with PH & Transplant please!

[coloradogrower303]

Hello all,
New to this so bare with me. We are growing indoors, in a grow tent with soil (Fox farm ocean blend). We only water using distilled water that is the right pH and ppm. We have been testing our plants pH with the soil tester and it has been high around 8. We did a test on our run off after watering it with a digital one and it was 6.2. Which one is correct? If it is high, how do I correct it?

Readings from this morning are:
Water:
6.95 pH
40 ppm

Run off:
5.93 pH
828 ppm

Second question, I was noticing when getting the run off, that I have some roots growing out of the bottom of some of my pots. They seem to be doing okay, but should I transplant? Thank you any help!

 

[coloradogrower303]

Here are some photos of the roots I’m talking about.

 

[Vagician]

Always water with the target pH. Even if your soil is at 8.0 you don't want to do something drastic like hit it with 4.0 to drop the overall soil pH. Soil is usually somewhat forgiving with pH variations because of something called buffer capacity. The probe type soil pH testers that you push into the soil aren't usually too accurate, I'd trust the digital meter/runoff water more than the soil probe. I like to water with 5.7-6.3 no matter the stage of growth. The 828 ppm runoff compared to the 40 ppm going in means there is excess nutrients in the soil that are coming out, not really something to worry about at this phase of growth, it just means you are not delivering those nutrients to the plant and dumping them instead. The distilled water is likely stripping nutrients from the soil so consider switching to tap water if the initial EC/ppm of that isn't over ~200 (because of calcium and magnesium in your tap water). This will help from pulling nutrients out of the soil even though the runoff EC/ppm might not change much. If you want to learn other soil tests check this out: https://www.greenhousegrower.com/pr...h-method-and-saturated-media-extract-methods/

As far as those roots, it may be time to transplant. If you can (carefully), turn the pot upside down holding the main stem/trunk and lift the pot off slowly. If the plant's roots hold onto the soil and you can see them starting to circle then it is transplant time. If, instead, soil starts to fall everywhere as you are lifting the pot then place the pot back on and wait a few more days. Judging by the height of vigor of your ladies I think you're ready.

 

[coloradogrower303]

Thank you so much! This is exactly what I was looking for! I will do some testing of my tap water & try your trick to see if I need to transplant. Thank you so much again! I will report back!

 

[Aqua Man]

Are you feeding nutrients?

Ok let's go through some basics of ph and ppm so you get an idea why I recommend what I do. Going to try to keep this brief and will answer questions if you have.

Distilled water should have a ppm of 0. It will have a very unstable ph but this is not a bad or good thing just a fact. Carbonate and bicarbonate are what will provide buffering of the ph. So since distilled water has none the ph will change very easily. Thus your soil will easily change the ph of the distilled water to the soil pH. This is good since most soils are built to buffer to the ideal range around 6.5 by combination of acidic and basic makeup (will explain further if you want)

Now that soil contains buffered and added nutrients. So don't mess with it. From my understanding it an be a little rich on nutrients for young plants but they will grow into it.

In short so not add nutrients and do not ph your water. The soil will buffer the ph and contains all the nutrients you need for quite some time (at least a month).

 

[coloradogrower303]

We aren’t adding nutrients because like you said, the soil has it. So basically continue to use distilled water, but don’t mess with the pH and add as is, is that correct? Thank you so much for your help!

 

[Aqua Man]

Always water with the target pH. Even if your soil is at 8.0 you don't want to do something drastic like hit it with 4.0 to drop the overall soil pH. Soil is usually somewhat forgiving with pH variations because of something called buffer capacity. The probe type soil pH testers that you push into the soil aren't usually too accurate, I'd trust the digital meter/runoff water more than the soil probe. I like to water with 5.7-6.3 no matter the stage of growth. The 828 ppm runoff compared to the 40 ppm going in means there is excess nutrients in the soil that are coming out, not really something to worry about at this phase of growth, it just means you are not delivering those nutrients to the plant and dumping them instead. The distilled water is likely stripping nutrients from the soil so consider switching to tap water if the initial EC/ppm of that isn't over ~200 (because of calcium and magnesium in your tap water). This will help from pulling nutrients out of the soil even though the runoff EC/ppm might not change much. If you want to learn other soil tests check this out: https://www.greenhousegrower.com/pr...h-method-and-saturated-media-extract-methods/

As far as those roots, it may be time to transplant. If you can (carefully), turn the pot upside down holding the main stem/trunk and lift the pot off slowly. If the plant's roots hold onto the soil and you can see them starting to circle then it is transplant time. If, instead, soil starts to fall everywhere as you are lifting the pot then place the pot back on and wait a few more days. Judging by the height of vigor of your ladies I think you're ready.

RO/ distilled does not strip nutrients any more than tap water. If anything it helps keep the balance of nutrients. Adding tap with calcium or other nutrients can slowly alter their ph although unless like you say it over 200ppm it's unlikely to see any negative effects in the time period of a grow cycle.

Altering the ph of feed water is a waste imo. Acids added don't really stay in the soil like they do hydro and something like citric acid often used in soil breaks down in then than 24 hrs and more likely less than 12hrs. These ph swings are not beneficial to plants. The soil is the buffer... If there is a ph problem it's either due to over feeding, imbalanced nutrients or poor soil makeup. You should never need to ph feed water unless you are adding something like silica

 

[Aqua Man]

We aren’t adding nutrients because like you said, the soil has it. So basically continue to use distilled water, but don’t mess with the pH and add as is, is that correct? Thank you so much for your help!

Yes

 

[Aqua Man]

I want to add though there is nothing wrong with using tap water. If the ppm is relatively decent you will not see an issue in the time it takes for a grow. The smaller the amount of soil the more influential water source can be.

My water is about 120-140ppm and reviewing my water report for makeup I would have no issue at all using it for soil as I'm about to be doing shortly.

You can google your local water report and it will break down the elements in it. The key factors are cal/mg and sodium if I had to pick 3. Tap water is also buffered to be over 7ph since acidic water can damage coatings and leech heavy metals into the water.... Flint ring a bell.

If you have questions on interpretation of your water report I can give you a hand on that.

All in all a well buffered soil like you have is pretty forgiving in terms of ph.