papheteer
Well-Known Member
To those that adjust their water and fertilizer solution pH, what do you aim for? Also what type of chemical do you use? Thanks!
The pH of the applied solution is not the only factor in what determines the pH. The potting medium, the plant, and micro flora and -fauna all affect the rhizosphere pH.
Many moons ago, a few folks experimenting with semi-hydroponics for the first time measured the pH of the reservoir. Starting with a solution pH of 6, depending upon the time of day, and time since the plant was watered, we saw readings as low as 3.4, especially early in the morning. Some were higher than 7, but I don't recall exactly.
In that case, the medium played no role, as the LECA was inert, so I attributed it to the plant itself.
I think the best way to see what's really happening is to saturate the medium with your regular solution, wait an hour or two, then barely dribble more solution through the pot. Collect the drainage and measure that.
After seeing the swings in pH in S/H pots, I have decided to take a much simpler approach. I just don't worry about it.
I recall Rick mentioning that a ph of 5.8 was ideal for nitrate absorption.
I would think aiming for 5.5 to 6.5 depending on what conditions the plants prefer, and depends on if you need to raise or lower the pH. Citric acid could be used to lower and baking soda or potassium bicarbonate could be used to raise
Elmer Nj
Has anyone tried adding to LECA in s/h chips of dolomite or oyster shell to try to buffer plants that come from karst/limestone regions? I'm not aware of PK growing s/h successfully; maybe it could be it needs a buffered higher pH?
i try to aim for 6.5 usually. but i haven't checked/adjusted pH in over a year. 30-10-10 added to tapwater brings it right in line for me so i just go with it.
i am in the middle of switching to orchiata though so i need to do some tests with the runoff vs fir bark.
In that case, the medium played no role, as the LECA was inert, so I attributed it to the plant itself.
Has anyone tried adding to LECA in s/h chips of dolomite or oyster shell to try to buffer plants that come from karst/limestone regions? I'm not aware of PK growing s/h successfully; maybe it could be it needs a buffered higher pH?
PK will grow using the s/h method but it grows tremendously better if you water overhead...
If you are doing semi-hydro culture properly, you DO water from overhead.
Has anyone tried adding to LECA in s/h chips of dolomite or oyster shell to try to buffer plants that come from karst/limestone regions? I'm not aware of PK growing s/h successfully; maybe it could be it needs a buffered higher pH?
I started growing a PK seedling in s/h buffered with oyster shell in July of 2014. When I was setting it up I was shooting for a flooded pH of 8.0 measured a couple of hours after flooding. At the time it looked to be a few months out of flask. Now one growth later it is in spike. It is still a small plant with a leaf span of 11 inches. But it seems to be happy enough.
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