Seaweeds may drastically lower PH to dangerous levels?

[Ray]

Originally Posted by tmoney

you kelp even thru winter? trying to decide what to do with our paphs, to kelp or not to kelp (thru winter) is the question....

Most of my collection is paphs and phrags - they get a monthly Kelpak treatment all year.

I will be potting up some deflasked paph seedlings tomorrow. They are currently submerged in a Kelpak + probiotic bath overnight.

[DavTom]

Originally Posted by Ray

Davide,

The pH in the reservoir is quite transient, in my experience. It can change rapidly, and that is primarily controlled by the chemical processes going on in the plant, and those change by the time of day or night and other environmental cues.

Unless you simply like to be argumentative, I don't understand how you can tell me "it's dangerous for my plants" when I clearly stated those were measurements (from a calibrated instrument) and I observed no harm to the plants? In fact, after several other folks tried the same testing with the same result, I simply stopped worrying about it.

No intention to be argumentative. I was just trying to help. I like these topics, that is another reason for commenting further.

Your plants are surely doing great, no doubts about that.
But a PH of 3.5, even if my plants were doing great and it was only measured occasionally, would still sound as a warning bell to me...maybe just to me.

Dav

[Ray]

I guess what I'm getting at is that pH is a measure of free H+ ions compared to OH- ions. pH tells us the relative measure, but not the concentration.

I'll use a ridiculous scenario to make a point:

Solution 1 - contains 10 H+ and 1 OH-
Solution 2 - contains 10000 H+ and 1000 OH-

Both have the same ratio of H+ to OH-, so have the same pH, but Solution 2 is a much stronger acid than Solution 1.

If solution 1 was poured on the plants, it would very soon be overwhelmed by the plant/medium/microbes. Solution 2 might kill it.

Citric acid is often added to fertilizers to enhance solubility, especially if they contain calcium, and the resulting solution pH is fairly low. Citric acid, however, is such a weak acid, that its acidity is "squashed" by almost any addition.

[DavTom]

Originally Posted by Ray

I'll use a ridiculous scenario to make a point:

Solution 1 - contains 10 H+ and 1 OH-
Solution 2 - contains 10000 H+ and 1000 OH-

Both have the same ratio of H+ to OH-, so have the same pH, but Solution 2 is a much stronger acid than Solution 1.

If solution 1 was poured on the plants, it would very soon be overwhelmed by the plant/medium/microbes. Solution 2 might kill it.

Thanks for pointing that out, I agree with that.

But how can you be sure that the solution you may have in the reservoir is like Solution 1 and not like (or closer to) Solution 2, unless you have done extra tests (like mine below) to check it?

If it was a very soft (i.e., very low TDS) solution, in which you know that your are not adding any significant amount of H3O+, then I would agree with you.

But look at my case: I have added a very small amount of Seaweed solution (just at 1/7 of recommended dose) in 5L watering solution and the PH dropped by 1.5 units. This does not tell me yet about the concentration of H3O+, but just the ratio between H3O+ and the OH-. Fair enough. That's why I wanted to see how much of my tap water (which is very alkaline with a PH of 8.4 - it has 10KH German degrees) I needed to add to neutralize that drop of PH. Well, as I wrote in my previous post it took me 1.5 L (or even 2L I do no remember it now by hard, but it is in the post) to neutralize the PH drop. This means that that small amount of seaweed added a dangerous amount of H3O+.

If I were you, if you did not do it yet, I would make a simple test like mine to make sure you are far enough from Solution 2 scenario.

Dav

[Ray]

Originally Posted by DavTom

If I were you, if you did not do it yet, I would make a simple test like mine to make sure you are far enough from Solution 2 scenario.

Dav

Davide - I did that testing a good 15 years ago or more. I have not bothered adjusting my solutions since, and I have experienced no issues.

That said, I basically only use 3 products on them, so that's been a constant.

[DirtyCoconuts]

I think there is also an acidity case alkalinity issue.

Plain water will change a lot more than any solution that is already at all buffered.

I use pure rain water with a homebrewed batch of Inococur and k lite every water. Monthly kelpmax. I have only done ph testing maybe yearly. I don’t really worry since, as Ray said, I don’t change much.

[DavTom]

Originally Posted by Ray

Davide - I did that testing a good 15 years ago or more. I have not bothered adjusting my solutions since, and I have experienced no issues.

That said, I basically only use 3 products on them, so that's been a constant.

OK, Ray. Sorry I could have stopped this conversation earlier, but this did not come clear to me from your previous posts. I wrongly thought you had checked only the PH and not also the H3O+ concentration.

One last point still related to PH. What do you think about low PH and micronutrients toxicity? Some microelements (in particular iron and manganese) become drastically more available for plants uptake at lower PH and this may easily lead to toxicity. Frankly speaking, I do not know if this has a dependency with H3O+ concentration.

What are your thoughts about this? Did you do any tests, or you simply assumed there is no problem because your plants are doing fine since a long time?

Dav

[Ray]

Originally Posted by DavTom

OK, Ray. Sorry I could have stopped this conversation earlier, but this did not come clear to me from your previous posts. I wrongly thought you had checked only the PH and not also the H3O+ concentration.

One last point still related to PH. What do you think about low PH and micronutrients toxicity? Some microelements (in particular iron and manganese) become drastically more available for plants uptake at lower PH and this may easily lead to toxicity. Frankly speaking, I do not know if this has a dependency with H3O+ concentration.

What are your thoughts about this? Did you do any tests, or you simply assumed there is no problem because your plants are doing fine since a long time?

Dav

I rely mostly on my observation of healthy growth, but it is my understanding that 1) micronutrient toxicity occurs at extreme pH levels only, 2) solution pH is quickly “adjusted” in the rhizosphere, and probably most importantly, 3) the concentration of those elements are included in fertilizers in trace amounts to provide the necessary masses without overdosing them.

Most of the time, when trace element toxicity is encountered, it is when they are applied excessively via soluble trace element mixture, in addition to what is provided in the “base” fertilizer.

[K-Sci]

Originally Posted by estación seca

Under my conditions plants in S/H with monthly Kelpmax/Kelpak grow better than plants in other media.

ES, how do you dose KelpMax in S/H monthly? My intuition, which is certainly not 100% reliable, is that if Kelpmax is in the S/H water, it would be like watering with Kelpmax at every watering. That is, unless you replace the water after a day or so.

-Keith

[Ray]

Originally Posted by K-Sci

ES, how do you dose KelpMax in S/H monthly? My intuition, which is certainly not 100% reliable, is that if Kelpmax is in the S/H water, it would be like watering with Kelpmax at every watering. That is, unless you replace the water after a day or so.

-Keith

Certainly, in S/H, the plant would be exposed to the product longer than if applied to a potful of bark, but if you only apply it once a month, it isn’t anything like using it at every watering. The ingredients are absorbed relatively quickly, those that aren’t decompose, and the next time you water, you’ll be flushing the pot anyway (assuming you’re watering a semi-hydro pot correctly).