Absynth420

OK. I am growing 4 plants in a deep water culture hydroponic system. They were all doing very well on the 3 part General Hydroponics grow, micro, and bloom solutions. they went into flowering a little over a month ago and i added liquid Kool Bloom to the mix as per the suggested amounts for the type of system I am using. I have been following the guidelines on the GH nutrients as well. Two weeks ago, they all started to brown at the edges of the leaves. they are not curling under, and it does not seem like an over-fertilization issue.
i am thinking they do not have enough potassium, but i do not want to risk adding more bloom solution if they are already over fertilized.

the buds are dense as hell (one cola is as big around as a volleyball), with monster crystals and trychomes, those all look VERY healthy. its just the leaf edges that are making me worry.

is there a different nutrient regiment that i need to follow for this line of products? since im sure the company dosent offer an official nute table for cannabis. or should i flush the plants as fast as possible? im fairly experienced in growing hydroponically, but this is my first time in a deep water culture system, so any help would be good.

oh, the plants are only in rockwool and hydroton in 5" net pots... if that helps any. the roots suspend into a few inches of air and then into the water/fertilizer mix, which is continuously oxegenated with a 24inch airstone. i change the solution weekly and take very good care to maintain a clean garden.

any ideas? im needing help soon, its almost getting time to flush with pure H2O anyway (they look about a month from being ready to pick).

thanks...

Absynth420

BUMP!!!

sorry to have to resort to that, but im leaving town for a few days on friday, so i need to know asap!!!!!!!!!!!!



PLEASE HELP A FELLOW BOTANIST OUT!!!!!!!!!!

farmergiles

In that case you probably know more than me but someone else will probably be able to help but you`ll need to post pics.

I believe the chances of burning them through under fertilisation are slim, often the recommended amounts tend to be on the high side.

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Cerebro

I dont know too much about either dwc, or the products you are using.
I'll throw you my 2c, since you aren't getting far.
I'd flush, then feed a final bloom at half, or quarter, usual strength in a week, then reassess in two weeks.

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smallarmsfire

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Absynth420

thanks for all the advice.. and ill answer any questions you guys had.

1. yes, my main ventillation IS hooked up to the light timer, but i have a large ceiling fan running 24/7. i am also growing shrooms in the same room, but the humidifier setup is completely enclosed and there is no leakage.

2. R/O water ALL THE WAY!!!!! gotta keep the TDS low so it doesnt get too high when i add the nutes.

3. It is a one container DWC.

4. I DO completely change out the solution, i make a new batch every time and i wash the container very well. and flush the roots with the R/O water between every changing to eliminate salt build up.

smallarmsfire

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Absynth420

nope on the cal/mag additive... ill go pick some up tomorrow and see what happens. just got back from vacation and they had a little light burn, but since ive got 4 different strains in the same container, ive got to underfertilize some and over fertilize the other 2. so ive worked out a delicate balance between the nutes, and im adding another fan.

next cycle im using all the same strain and ill try to post a pic of the garden by this evening so you guys can see.

im impressed at the reult, even with the light burn and leaf necrosis, the buds are massive and crystal coated like a mo' fo'!!

edit to add: ive also switched the fan to NOT be on the same timer as the light, so now its 24 hrs a day + a ceiling fan

edit again to add photos:

pic 1: a general overview of the setup
pic 2: a little closer up image to show growth better
pic 3: one of the colas. there is a little nute burn and light burn
pic 4: another cola, better developed and almost ready for harvest. this plant did not exhibit as much nute burn and no light burn.
pic 5: a closeup of the worst burned, i think its either nute burned or the mag/cal defficency. also this plant got a little too close to the light while i was out of town and got a little burned from the light.


edit again to add: now that i researched cal/mag, i dont think its light burn at all. its saying that this deficiency can also make the leaves curl upward and brown on the edges... EXACTLY what my plants are showing me.

THANKS SMALLARMSFIRE. i think that was just what i needed. if you could take a look at the pics and let me know again what you think, i would greatly appreciate it.

Attached Images

     

smallarmsfire

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Absynth420

thanks a ton mate!!! im just gonna flower them out then, since theres no good hydro store around here, the only cal mag i could find was for soil.

but now i know... and knowing is half the battle!!!

thanks again smallaramsfire!!! you tha man!

farmergiles

Instructive pics.

A dash of epsom salts would sort out magnesium def. Not sure what to do about calcium but you may be able to get something from chemist`s/ healthfood shop...

Take this with a pinch of salt `cos I`ve only ever done soil but I think any viable source of calcium should work- the cal mag you found for soil should do the trick just be careful with the dosage.

They`re looking so good it would be a shame to leave them needy now...

How long before you`re gonna harvest, Absynth?

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Absynth420

well as for the salt idea, i think the reason im suffering the cal/mag def is because if salt build up on the roots from improper flushing the last time i cleaned the reservior, and going out of town made it worse.... as for harvest, there is one that looks like itll be ready an about a month, one in five weeks (?) and the other 2 look like they need a month and a half at least, judging by the red hairs and crystal development...

farmergiles

Sorry, my bad, I didn`t make myself clear "Take this with a pinch of salt" means don`t take this as Gospel truth, not that you should add sodium chloride.

However Epsom salts can be added to sort out mag def, half a teaspoon to a couple of gallons works wonders, I almost always get mag def otherwise (I`m pretty sure about that) but I`m not sure what exactly you can use for cal def but I`d wager if the additive you could get for soil is water soluble (surely it is) then it would work fine although I`d only recommend low dosage (less than the given rda anyway).

Just 1-1 1/2 months is a long time to let them grow out with a deficiency and they look so good otherwise.

And yes I`m sure you`re right a build up of unwanted salts would definitely cause difficulties in absorbing certain nutes and minerals.

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Cerebro

You can add some bonemeal, or crushed up egg shells as a calcium source.
but not for dwc.

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Kishar

nice buds

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Absynth420

well theyre all fixed up now... cant undo the rusty edges, but otherwise the problem has been fixed. i just used some GH Flora Kleen for 3 days to get rid of the buildup. then went back to their reg nute schedule with some Cal/Mag Plus just in case and i already see and smell a difference, so i dont think theyll suffer from the cal deficiency.

Cerebro

cool, should work out well.

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farmergiles

Sorted, well done.

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smallarmsfire

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Absynth420

im using the basic GH grow, micro and bloom solutions. with the floralicious grow and bloom, and liquid kool bloom to supplement during flowering. im basically following the guidelines on their Keep It Simple Recirculating program. you can check them here...

GENERAL HYDROPONICS

it also has an expert program, but i dont have all those nutes yet, so im gonna use that schedule for the next crop. i would NOT reccomend following the guidelines on the bottles themselves. they are not as in-depth as the feeding schedule in the link.

i started out with a 1/4 solution of the reccomended mix, and worked my way up til i found a good ratio of water to nutes. youll have to play around with it, as different strains require different nutrient levels to thrive. so start low, and work your way up to higher levels.

and keep a diary of your progress. i know it may sound lame, but you need to remember how much nutrients you used precisely and when. and if your memory is like mine, youre gonna have to write that shit down!!