Nutrient uptake questions

Right, I was going to change out my res for a fresh solution - purely because I feel like ppm's of each individual nutrient could be well off over the course of 3 or 4 weeks

Now that's going on the "plants only uptake what they want" style of thinking and advice given on such forums..

Which begs the question - if plants only take what they want out of nutrient solution, why do we have such problems as nutrient burn/toxicity?

967 said:

Right, I was going to change out my res for a fresh solution - purely because I feel like ppm's of each individual nutrient could be well off over the course of 3 or 4 weeks

Now that's going on the "plants only uptake what they want" style of thinking and advice given on such forums..

Which begs the question - if plants only take what they want out of nutrient solution, why do we have such problems as nutrient burn/toxicity?

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Passive, Ionic Uptake. It's what regulates fruits and vegetables through a cool and groovy organic process.

Cannabis? It's a hyper/dynamic accumulator and sucks up nearly anything it can touch. It has additional pathways of uptake, besides passive/ionic. High quality cannabis is about providing a balance of what the plant needs, in only the quantities it can reasonably convert at the time. Should your nutrient profile have been balanced to begin with (something along the lines of Lucas or very similar), there wouldn't be any need to change the solution. I run one flowering res for 3 months, till the changeout at the end. Top offs are pure r/o, pH adjusts are done with only nutrients.

The same also applies to organics. What the plant needs in a balanced mix, only amounts the plant can convert at the time.

I'm not sure if I need to change or Not, more just for my own peace of mind. I throw flairform 2-2-6 at it with a little extra pk as a supplement, without any more thought about what it needs or wants, unless I see deficiency which is rare. Could be wasting my time with the extra pk but hey, quality is excellent and yields aren't too bad..

I never really understood how folks can go months without a res change but I've heard it many times.

I cannot go more than 14 days max without a res change. I know it's ready for a change when the aeration pump comes on and there is a slight fermented vegetable odor.

As the plants progress thru flower they use more nutrients faster and the res gets changed every 7 to 10 days depending on when I smell the ferment.

The main rule i've always heard was that when you have added back 50% or more topoff water, then it is probably time for a res change. Plus, res changes are a great time to do a flush of your media with plain water.

Best of luck

Not so much in veg (unless you re vegging a bunch of plants) but definitely in bloom

Also female plants dump a bunch of crap into the rez causing pH and imbalanced nutrients

Farm Hero said:

I never really understood how folks can go months without a res change but I've heard it many times.

I cannot go more than 14 days max without a res change. I know it's ready for a change when the aeration pump comes on and there is a slight fermented vegetable odor.

As the plants progress thru flower they use more nutrients faster and the res gets changed every 7 to 10 days depending on when I smell the ferment.

The main rule i've always heard was that when you have added back 50% or more topoff water, then it is probably time for a res change. Plus, res changes are a great time to do a flush of your media with plain water.

Best of luck

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I run DWC, constant aeration. The res is clear and clean at day 70+.

Pet Flora said:

[FONT=Arial, Helvetica, sans-serif]Not so much in veg (unless you re vegging a bunch of plants) but definitely in bloom

Also female plants dump a bunch of crap into the rez causing pH and imbalanced nutrients

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Haven't seen this happen in 16 years of hydro. I use balanced nute mixes (close to Lucas) and Lucas res management methods. pH and ppm are rock solid predictable all through flower, right up to the flush. [/FONT]