Seaweeds may drastically lower PH to dangerous levels?

[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.