Is the ph of a plant being grown in soil, what the input water measures, or what the runoff measures?
both... just use powdered dolomite lime and you don't have to worry as much.... water with 7.0 water(distilled water) and the lime... simple... if you have problems... sprinkle more lime and flush.... repeat
Thanks for your comment. I am curious as to what measurement constitutes the plants ph level though. Both are rarely, if ever the same as I'm sure you must know. Any comment on the topic at hand? And possible even a vote on the poll?
Runoff is the one you are trying to get to a certain target, 6.4-6.8 in soil. You measure your input pH as a way to know, through trial-and-error, what level will get you the runoff pH you want and then how to keep giving that same level. For example, let's say your input water is 7.0 and your runoff pH is 5.8 -- too low. So you will want to raise your input water pH. But to what level? You might get it 7.5 then try watering with that, and let's say the results is runoff of 6.2. OK, getting closer, next time you might try your input at 8.0 and then your runoff is 6.5, perfect. So now you know that 8.0 is what your input needs to be, and you measure your input each watering to make sure you are getting the right input level. Of course continue to measure the runoff pH to make sure the result still is where it needs to be, and adjust the input some more if needed.
Great explanation. Exactally what I know to be true. I am trying to make a point and educate folks also. I get people ( in this thread http://forum.grasscity.com/indoor-marijuana-growing/950022-ph-issues.html and in my grow journal) who are telling me that input is what matters. Toast, if you have time please reply to the above post I am adding 9.5 and getting 5.5 5.4, 7.0, and 6.5 runoff from my four plants. My local hgt supply store did not have lime but I will be getting some soon.