General Soil pH Question

So I was looking at the FF trio feeding schedule and I noticed they have a chart that shows how pH limits the availability of certain essential elements for plants...i noticed that at a soil pH of 8.5 all of the nutrients necessary are fully available, same is true for just around 5.0...the only ones that are somewhat limited are copper and zinc...this makes me wonder if i'm missing something about the 6.3-6.8 desired range for soil....in other words, would it be just as good to keep soil at 8.5 as it would between 6.3 and 6.8 since the nutes are available at the same rates at both pHs? or is there something about alkalinity (or acidity if you went with 5.0) that is dangerous for the plants? whats up with this?

Dr.J20 said:

So I was looking at the FF trio feeding schedule and I noticed they have a chart that shows how pH limits the availability of certain essential elements for plants...i noticed that at a soil pH of 8.5 all of the nutrients necessary are fully available, same is true for just around 5.0...the only ones that are somewhat limited are copper and zinc...this makes me wonder if i'm missing something about the 6.3-6.8 desired range for soil....in other words, would it be just as good to keep soil at 8.5 as it would between 6.3 and 6.8 since the nutes are available at the same rates at both pHs? or is there something about alkalinity (or acidity if you went with 5.0) that is dangerous for the plants? whats up with this?

Click to expand...

ph should be the same in the soil as ur feed, in hydro your water is ur "soil" so its gunna be at 5.5-6.3(zone plants like) depending on ur plants likes, soil acts like a filter as well so what ever ur run-off ph is, is what ur plants are getting(the water that comes out the pot after watering) high than 6.3 ph ur going to have an easy time getting bugs and etc.

pm if u need anything else

I guess I wasn't clear....I recognize that we all think that "the zone plants like" is 5.5-6.3 for hydro and 6.3-6.8 for soil. The reason for this zone, as i understood it, was that the pH limits the availability of certain elements and nutrients (eg. nitrogen, phosphorous, copper, zinc, manganese, etc.). The range which provides peak availability of the necessary nutrients shown graphically on the feed schedule for soil feeding of FF trio (available at their website). I noticed that on their chart the nutes are available at pHs of above 8.0 and around 5.0 as well as the ranges specified for soil and hydro. SO, i pose a hypothetical question: if my soil pH were at 8.5 and my nute-water pH were also at 8.5 would I run into trouble since the chart shows pretty similar availability at 8.5 as it does in the 6.3-6.8 range? Or, to put it another way, what exactly causes the nutrients to be "locked up" or "locked out"? I recognize that certain pH levels cause salt buildups; and I'm aware that salt build up is related to the hydrogen ion [H+] concentration is what pH is but what is the piece i'm missing? why pH 6.5 instead of 8.5 if the nutes all become available at 8.5 again? look at the chart for what i'm talking about...