Deep Water Culture grow, Possible Nitrogen toxicity, need advice Madam's and Sir's.

[sogman]

So I think I have a case of nitrogen overdose. Getting clawing. Photo is current day (most recent)

The bucket is 950ml, I use 500ml of aged water, water treatment plant doesn't use chloramine only chlorine at 1ppm so it evaporates readily in a day.

Here is my mix formula:
__________________________

Phosphoric acid = 4 drops
______________________

H2O2 = 1.5ml

1/500 = 0.002
0.002 x 500 = 1ml L.S.W.

KNO3 = 0.13 g
CaNO3 = 0.50 g
KH2PO4 = 0.33 g
MgS = 0.25 g

_______________________

Amended 75% Veg Formula

H2o2 = 1.5ml

L.S.W. = 1ml
KNO3 = 0.0975
CaNO3 = 0.375
KH2PO4 = 0.2475
MgS = 0.1875

_______________________

This photo is from ten days prior roughly, i was having issues with nitrogen deficiency at that time but since started using a Nitrate combination of Cal Nitrate & Potass Nitrate to balance the NPK better.

I began supplementing more heavily with P & K under advice from this chart.

The rootball in the netcup has grown into a peat pellet.

My thoughts on the matter is perhaps the rootball is saturated with a high amount of nutes and needs to be flushed?

I amended my formula and scaled everything back by 25%.
H2o2 was kept at 3% consistent with earlier formula, same with liquid seaweed @ 1/500th. = 1ml.

I am thinking I am going to maintain N @ 185ppm and lower the PK levels to 50% original values.

Any advice on the matter greatly appreciated.

 

[sogman]

Here is a photo of the root development for reference, sapling is actually quite old, probably 60 days old because I had it in poor conditions earlier.
It is now under 100 watt's of multispectrum light with infrared and ultraviolet as well as far red, close red, far blue, and close blue light ranges.

 

[sogman]

Root growth really taking off here, spoke with a local expert at the greenhouse couple blocks away.

He recommended lowering h2o2 concentration to 1.5% possibly 1% and slowly increasing over time if I notice staining coming back.

 

[f-e]

Where is the feed chart from. It seems very unlikely. I don't see anything in your feed that makes it brown either. What's LSW? I guess your base feed, that might be alright without the rest added.

I chase my own tail with formulations sometimes. I don't think copying someone else's unverified works doing you any favours. From another planet that set of ratio's.

100-100-200 is the basic starting point. Things can move quite a way from that but an ill plant getting 50% more npk and going brown at the root isn't good. I see some is slimy that tried to extend out, but that's a small root system. I would drop the npk and Ca but the Mg looks ok. I'm unsure of LSW where the rest comes from

 

[sogman]

Where is the feed chart from. It seems very unlikely. I don't see anything in your feed that makes it brown either. What's LSW? I guess your base feed, that might be alright without the rest added.

I chase my own tail with formulations sometimes. I don't think copying someone else's unverified works doing you any favours. From another planet that set of ratio's.

100-100-200 is the basic starting point. Things can move quite a way from that but an ill plant getting 50% more npk and going brown at the root isn't good. I see some is slimy that tried to extend out, but that's a small root system. I would drop the npk and Ca but the Mg looks ok. I'm unsure of LSW where the rest comes from

Thanks for the advice I will amend the mix to 1 - 1 - 2

L.S.W. is Liquid Seaweed. 1 ml/500ml = 1/500th = 0.2% = 2000ppm
I also reduced my h2o2 concentration to 1%

Thnaks for your help, I appreciate it!

 

[sogman]

I've been doing some nosing around it looks like I can increase my liquid kelp (micros) supplementation to 1.8ml
= 80% increase

Product is rated @ 0.1N - 0.1P - 0.5K

 

[f-e]

So you have NPK Ca+Mg but nothing else? Where is your Sulphur. Iron, Zinc, kitchen sink? There are almost a dozen essential elements.

 

[sogman]

So you have NPK Ca+Mg but nothing else? Where is your Sulphur. Iron, Zinc, kitchen sink? There are almost a dozen essential elements.

I have liquid seaweed, I was also recommended Silica and Boron as next macro-micro's or pseudo-micro if you will.
Zinc is like really trace stuff.

Sulphur and Iron I do have, the sulphur is part of the Mg Sulphate sats, and the iron I add Iron Chelate per the instructions 5g / 10litres

So 500mg for 1 litres and because I am using 1 British Imperial Pint (500ml) I split the dose to 250mg / 500ml.

 

[sogman]

Now that I do more reading I think my friend was wrong about adding Iron chelate lol

I just swapped the water to pH buffered water (6.2) and added 250ppm h2o2.

I might flush it for 24hr and then try your 1-1-2 supplementation and omit the Fe because Liquid Seaweed is already very nutrient dense.

Apparently Iron is good at locking out nutrients particularly calcium bonded stuff so I was depriving the plant of probably calcium and nitrate by accidentally overdosing it.

 

[f-e]

Zinc is very trace yes. It's essential though and your plants are asking for it. We can't single it out for attention though. Your mix might work in soil but in water culture you need to provide everything. You won't get through with one wing and a prayer.

The essential list:
1. Nitrogen 2. Phosphorus 3. Potassium 4. Calcium 5. Magnesium 6. Sulphur 7. Iron 8. Manganese 9. Copper 10. Zinc 11. Boron 12. Molybdenum 13. Silicon 14. Sodium 15. Vanadium 16. Cobalt.

 

[sogman]

Latest update, plant is doing great on 1 - 1 - 2 ( N - P - K ) and 2 - 1 - 0.5 ( K - Ca - Mg )

Problems with hyper-pinnate leafs & die-off were fixed by increasing L.S.W. (liquid seaweed) from 1/500th to 1/250th total solution volume,
and also moving the plant further from high power C.O.B. L.E.D.

Thank you for the help friends, I got some great advice on here!

 

[Guest]

Leaves twisted downwards, dark blotches, dark margins.. Needs extra calcium phosphate, like every led grow.

 

[sogman]

Leaves twisted downwards, dark blotches, dark margins.. Needs extra calcium phosphate, like every led grow.

The Dark blotches is a photographic anomaly, there isn't any blotches just some yellow leaves from before I dialed in the nutrients better.

I could probably try boosting the phosphate by increasing my calcium nitrate and omitting the potassium nitrate and just increase the mono-basic potassium phosphate dose.

The LED is very good, has Infrared and UV diodes, not just reds and blues.

I actually heard that the clawing (curling) is a sign of high nitrate.