Flushing plants to clear nute burn

[FastForward]

How long? I've put EC0 RO water in my tank and it's flooding every 3 hours for 10 minutes but I've no idea how long I need them to drink pureness before they can accept the full range of nutes again...?

Ta muchly

Farmer FF, who has spent today farming farming farming....soil, coco and hydro...oh my :)

EDIT: The tank has been RO for about 5 hours - the pH went in at 5.5 and is now 7.2! I take it that was all the nute in the roots and medium? I need to put the pH back to 5.8 or the plants will freak out more about pH changes, and also prolly need nutes. Can I put nutes in yet??

 

[Midnightgardener]

re

flush em for two days and then start again..i would keep them happy with some folair spray in the meantime

 

[FastForward]

flush em for two days and then start again..i would keep them happy with some folair spray in the meantime

2 days??! Wow, okey doke. Thanks for the help

 

[Midnightgardener]

re

check the leaves though, if they are still going upwards after two days and there is no difference..then flush more.
got pics?

 

[FastForward]

The rest of the plant looks healthy enough, maybe a tad off colour, but the lower leaves are spotted and burned or curled and just not looking healthy. New growth all looks fine. Wanted to make sure I could rule out pH swings and nute burn before I put them on full strength veg dose, hence the flush - figured better safe than sorry?

Since the initial burn I've changed the tank and put in 1/4th strength and kept it simple, with H202 and Hygrozyme and the new growth is largely okay but not brilliant. I think there's some nute lockout from either pH swings or nute burn and that's why they might be a bit small and showing various deficiencies. They're 3 weeks old and are ready to go full strength nute but not if they're not open to it...well, that's what I was thinking...

EDIT: Shit, I'm a stoney fool. I didn't check the pH of this RO - and it's pH 7.6, EC0. I haven't adjusted it at all....I assumed it was 5.5 like the last lot :( Is this v. bad? Should I ph down it?

 

[mace]

Yes you should check your ph. You want to let it range between 5.6 and 6.1.

Personally i like 5.6 to 5.9 for veg, and in flower i let it go to 6.1

 

[FastForward]

I normally do....have adjusted it down to 5.8...plants look even worse...one of my violators has split a leaf... :(

 

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Ok, guys and gals, this is now REALLY fking strange:

Why is it my pH is constantly rising and I cannot keep a stable pH? Beforehand I would have thought it was nutes being taken up, or temps, or something....however....this is in RO water during flush!

I woke up 10 mins ago, rushed into my growroom to check progress, and in my hydro tent the pH has risen from 5.8 last night to over 7 this morning. There's nothing in that tank apart from RO water (EC0, PH 7.6) and some pH down to bring it to 5.8.

When I just measured it again it showed 7.5! Why? How? What can I do to keep a stable pH?? If I can't do it with RO then there's no point in carrying on with the hydro methinks.....

Please help! This is totally weird on my planet. The hydroton shouldn't be carrying that much salt should it???? Especially given that I've only been feeding low doses....

EDIT: p.s. I'm seriously considering transplanting the Violator girls and the WW out of the flood and drain and into coco pots and sodding the whole hydro thing until flower - or at least until I can sort my pH issues out. For a nub, is this a good backup plan?

 

[dexter840]

i find the lower the ec the harder it is to keep the ph steady, but jump up over 7.5 in ro'd water is a bit puzzling to me...actually i'd go check the roots i suspect you see something we don't with the use of h2o2 and the hygrozyme. bad bacteria will push the ph up on you over a few hour period

 

[Gr8ful1]

Reverse osmosis water is lacking in certain elements that act as buffers to stabalize the ph of the water.I believe that calcium is the element.I add 1/4 strength cal mag to stabalize the ph and it seems to work

 

[FastForward]

Thanks guys - I've taken to cutting RO with tap just for that reason (more buffer, less crap) and so far so good, but I'm out of hydro and into coco now.

Dex - the roots have definitely suffered some stress and browning from an earlier aeroponic prop fsck up and bad bacteria could be an issue, although with the rises I was seeing it was likely something else (like un pH soaked hydroton).

Gr8ful - my next run with the hydro is going to go with pure tap water, no airstone (water pump to circulate instead) to see - but I think it has something to do with this water in particular, like the amount of dissolved bicarbs.

 

[stones]

its a 2 day flush with phd water 5.8