Flushing to fix nutrient lockout

[sneakyninja]

Ok so basically I screwed up and increased my plants DWC rez solution from Lucas 3ml/6ml to 5ml/10ml and im pretty sure caused nutrient lockout via this. Im now flushing at the instruction of a fellow IC'er at 1ml/2ml and overnight the plants look worse if anything. Should they go more downhill before improving and if so how long should it take to show improvement, its been about 24 hours.

Thanks,
SN

 

[Snype]

It'll take a few days to know what's going to happen. Just make sure to adjust the PH of your water.

 

[BudLove]

Hey Sneaky,

First - flushing in DWC is pointless... it's not like soil where the nutrients get locked up in the soil and must be 'flushed' out via water... in DWC if you dump the rez and refil it - well, the roots are now in a completely new solution and dont need flushing.

By removing the rez and replacing with simple straight water you are doing nothing but starving your plants.

Instead of that, dump your rez, refill it and ADD the appropriate nutes per your method (being Lucas)... that's it... give em a few days and see how they're doin.

And as previously stated, make sure your pH is right on through-out the process....

BL

 

[gr33nie]

Hey Sneaky,

First - flushing in DWC is pointless... it's not like soil where the nutrients get locked up in the soil and must be 'flushed' out via water... in DWC if you dump the rez and refil it - well, the roots are now in a completely new solution and dont need flushing.

Not true.

The leaf-tip burn indicates an evaporation of salts in the plant. Because there are too high a concentration of nutes for the plant to handle, the excess is evaporated out of the leaves - leaf-tips first, then progressively further along the leaf.

That's why when you burn a plant, it shows up at the margins first. If you let it get really bad, you'd eventually see the whole leaf look burned, shrivel up, then die.

Flushing in DWC simply removes all trace of nutes from the plant, and to flush you must provide only plain water. This then gives you a clean canvas to work with so to speak. Trust me - i'm fixing a nute-burn issue right now in a DWC system, and you have to flush with plain water for at least a couple of days before adding nutes again. Simply changing the res with a fresh solution certainly did not work for me.

There is a subtle difference between flushing a plant and leaching a medium, though the two procedures are inexorably linked.

 

[BudLove]

Not true.

The leaf-tip burn indicates an evaporation of salts in the plant. Because there are too high a concentration of nutes for the plant to handle, the excess is evaporated out of the leaves - leaf-tips first, then progressively further along the leaf.

That's why when you burn a plant, it shows up at the margins first. If you let it get really bad, you'd eventually see the whole leaf look burned, shrivel up, then die.

Flushing in DWC simply removes all trace of nutes from the plant, and to flush you must provide only plain water. This then gives you a clean canvas to work with so to speak. Trust me - i'm fixing a nute-burn issue right now in a DWC system, and you have to flush with plain water for at least a couple of days before adding nutes again. Simply changing the res with a fresh solution certainly did not work for me.

There is a subtle difference between flushing a plant and leaching a medium, though the two procedures are inexorably linked.

Hey Gr33nie,

Thanks for explaining what burnt is, but I dont think that's where our opinions differ. I'm still not sold on your treatment for burnt plants in DWC (soil, absolutely you're right on, but not in water culture).

You're saying - if I take a DWC rez, empty it out and fill it with plain water... this removes all traces of nutes from a plant. That is slightly incorrect as all it does is remove the nutres from the root zone so no more uptake will occur, it does NOT remove all traces of nutrients from the plant as a whole, otherwise the thing would just flop over and die.

Now based on doing the above, wouldnt the plant begin to feed on it's leaves and begin showing additional signs of starvation, mag def's, cal def's, etc?

Perhaps I can try explaining my logic this way:
You have a plant and it's burned from being in a hot rez. The leaves are dark green and tips are burnt. However, there is still new growth coming in from the top of the plant.

1.If you re-do the rez to the dose of nutes the plant needs, the new growth will begin to look better and the older growth may very well just stay nice and dark green until flower time, when the flowering alone will begin to pull the mobile nutrients from the darker leaves (might also require a longer flush period at the end of flowering to use up the excess N found in the burnt leaves)...but the burning will stop.

2.If you re-do the rez with PLAIN water, the new growth will not be able to get the immobilized nutrients from the lower leaves and therefore will begin to show signs of nute defs.....the older growth may very well just stay nice and dark green with the exception that the new growth will begin to pull mobile nutes out of them...and the burning will stop.


Which solution sounds more logical? To me, 1 gives the new growth what it needs and 2 does not (in the way of immobile nutes).... Personally, I opt for 1.

BL

 

[gr33nie]

Hey Gr33nie,

Thanks for explaining what burnt is, but I dont think that's where our opinions differ. I'm still not sold on your treatment for burnt plants in DWC (soil, absolutely you're right on, but not in water culture).

You're saying - if I take a DWC rez, empty it out and fill it with plain water... this removes all traces of nutes from a plant. That is slightly incorrect as all it does is remove the nutres from the root zone so no more uptake will occur, it does NOT remove all traces of nutrients from the plant as a whole, otherwise the thing would just flop over and die.

OK maybe I didn't explain it properly - it will begin to re-establish the equilibrium of nutes in the plant ie the excess buildup will begin to dissapate as the remaining (mobile) nutes will be re-distributed. You should obviously never flush until all nutes are used up. Then the plant will die of course.

Now based on doing the above, wouldnt the plant begin to feed on it's leaves and begin showing additional signs of starvation, mag def's, cal def's, etc?

Not if there is already an over-abundance of said nutrients for the same reason as mentioned above. Flush until the excess has cleared - a few days - and then re-introduce nutes to the res at a lower concentration, slowly building back up to the concentration before the burn occurred. This is the reason for re-introducing nutes at a lower concentration after a burn - there are actually already nutes present in the system. Adding back at the original concentration only burns the plant again.

Perhaps I can try explaining my logic this way:
You have a plant and it's burned from being in a hot rez. The leaves are dark green and tips are burnt. However, there is still new growth coming in from the top of the plant.

1.If you re-do the rez to the dose of nutes the plant needs, the new growth will begin to look better and the older growth may very well just stay nice and dark green until flower time, when the flowering alone will begin to pull the mobile nutrients from the darker leaves (might also require a longer flush period at the end of flowering to use up the excess N found in the burnt leaves)...but the burning will stop.

The burning will not stop in the older leaves if there is an over-abundance of nutrient already in the plant - the reason for the burn in the first place. The 'correct' dosage in the new res will simply add to the already over-dosed concentration. Yes, the new growth may be fine, but feeding already over-dosed older growth is not going to stop tip-burn.

2.If you re-do the rez with PLAIN water, the new growth will not be able to get the immobilized nutrients from the lower leaves and therefore will begin to show signs of nute defs.....the older growth may very well just stay nice and dark green with the exception that the new growth will begin to pull mobile nutes out of them...and the burning will stop.

Which solution sounds more logical? To me, 1 gives the new growth what it needs and 2 does not (in the way of immobile nutes).... Personally, I opt for 1.

BL

Ime, the newer growth never gets the chance to show signs of nute deficiency. By the time that the flush has ended, the burning has stopped. The new growth still looks healthy, and i've just started feeding the plant again so it never gets the chance to show any defs.

I'm still open to the possibility that i'm not understanding something here. My word is not gospel, and i'm not massively experienced, so please don't think that i'm picking a fight. I could be wrong - but i'm just going with my experience in DWC.

 

[BudLove]

hahah - well sorry for hijacking your thread sneaky....

Gr33nie - I too never consider myself to be in a position of 'knowing it all' or being unwilling to learn new techniques in order to gimme better bounties.

I think I have understood what you're saying and I also agree with portions of it. Although I'm not a botanist and have a very limited understanding of the plant's metabolism and overall storage/usage of food - my concern is usually focussed on the new growth when encountering a burn and not the older leaves which have initially displayed the condition.

However, I must admit I have also never had 2 plants show nute burn and then tested your method (plain water for a few days and then lower dose of nutes) compared to mine (refil rez, add back in nutes NOT to level that burned them, but level that they SHOULD have been at). So I can't say which works better or worse as I normally grow in a 6 bucket recirc DWC, so when one lady shows burn they usually all do.

So I think in our experience, we both have one portion of this method in common: once it's time to re-introduce the nutes to the plant do NOT add back the same amount of nutes that burned the plant to begin with. As that wouldnt make much sense even with a flush and removal of stored up nutes in the root zone.

Other than that I'd say Sneaky - the best teacher is usually experience and as we all see not everyone has the same as others... so run with it bro, go with the flush and the add backs and keep an eye on the EC. If you dont have an EC pen I'd highly recommend getting one, as it would have quickly caught your mistake in nute calculations (since it was probably almost 3000ms)...

BL

 

[gr33nie]

hahah - well sorry for hijacking your thread sneaky....BL

Shit - yeah. I forgot that there was actually a question asked here......

What he said ^^. EC pen is a must in hydro. You'll be fine.