Do you have any scientific data or studies to back up the statement that plants choose which nutrients to absorb? I'm not sayi g it's not true I'm just one who likes a little objective data in my acceptance of information.
I can find countless grows and have spoken to many who used to switch out there water weekly but have since changed their beliefs. Who really knows because there are so many things that can change from grow to grow. They saw not noticeable difference in weight or quality after switching to monthly and even only changing out when switching to flower.
Just a nice conversation not trying to push bbn uttons or start shit.
Hey man, yes just a conversation I know your not trying to start shit nor am I, I'm just relating my 25 years of grows and what we found to be best, like I say it very well may not be for everyone.
to your first question " If roots can "pick out" whatever nutrients they need as you say, why would a weekly res change be necessary to balance the nutrient load
the answer above about balance is right on, balance in solution is key , think of it this way your bobbing for apples and oranges, in the barrel is 50% apples and 50% oranges, you should have a relatively easy time getting either one , but if the ratio was 90% apples and 10% oranges, you'll probably have a hard time getting oranges and 2 will there be enough to fill your needs, well by letting your rez go for weeks on end that basically what happens, now consider there is at least 17 elements and some are easy to get and some are harder to get as is, but remember there is a whole other host of interaction with elements and how their absorbed IE potassium interacts with phosphorus, sodium, calcium and magnesium, but thats a whole other story , the idea of hydro is easy availability of nutrients and oxygen, an unbalanced solution only adds stress. to add to that it prevents unwanted build ups of ph up / down etc, helps to flush out diseases, bacteria, flushes the plant of waste and gives it a fresh drink of water, plus much more but you get the idea , Like I said its my experience from doing some pretty extensive testing in side by side room that rez changing made a big difference.
I'd ask what is the benefit to not changing the rez weekly, that benefits the growth of the plant or the system ?
Ok as far as which nutrients to absorb , I think its called a carrier cell that does it, I think its refereed to by other names as well but honestly I'd have to look it up. my understanding is the more leaf transpiration there is the more suction there is at the roots to draw in the water/nutrients , there is a specific cell to collect each specific element. thats why lighting, temps , humidity, feed etc are all equally important because what happening at the leafs is directly effecting whats going on at the roots and vise versa
the reason i say I never rely on ph or ppm meter, hardly use them is because I have my system down so pat that I know what x amount of rez water and x amount of mixed nutrients will give me, I really only use them if I think I made a mistake mixing something up, or to check now and again or once I have a strain dialed in to see what it is. you say Your PH PPM is going to tell you just as much about what your plants are doing as looking at them. But here is how I see it PH and PPM really doen't tell me anything other then what my solution is, if i'm running a new strain I just set my PH and PPM to a ballpark setting from there my plants tell me if i need to up or down PH or PPM, my plants set PH and PPM of my solution not a meter. once the plants set it I take note for next time.
one more thing about water in buckets, if you have a plant in soil and you over water it and continue to it will die, basically drowning it, it can't get oxygen, in a bucket full of water its really the same thing , the only thing keeping it alive is the air pump, its hard for the plant to get oxygen, I believe it adds stress and the plants tolerate it more so then thrive in it, and from our testing the best balance we found is what I stated above. anyhow those are my 2 cents
