Aeroponic Nutrient Levels

Hi All!

Long time no post and I hope the regulars are still around!!

I'm in the process of shifting to aeroponic/nft systems and I'm running into start-up trouble on the veg system. What I basically built is the system described in the June HT with improvements, including adjustable channel drains to maintain a bit of water in the event of a pump failure or power outage.

My veg system has 2 channels (5" vinyl fence posts) with 6 - 3" plant sites each (on 7" centers), fed from a 10 gal (actually 18, filled to 10) reservoir, using a 396 Gph pump, with 14 total sprayers.. Basically emulated an Aero Flo system, except my sprayers point up from the bottom. To prevent spray hitting the leaves I'm using neoprene inserts on the net pots..

For nutes, I'm using AN Sensi Grow.. plus 35% H2O2 (hydrogen peroxide) as a prophylaxis for root rot and other bad fungus.

So I packed this baby with rooted Silver Haze clones (typically a bit sensitive to nute levels), juiced the reservoir to 850 ppm, set ph to 5.8, and added 12 tbsp H2O2 (a bit over 1 tbsp per gal). Cycle timer was set to 1 min. on, 4 min. off. Changed the reservoir 9 days later, went up to 950 ppm, ph 5.6, still using H2O2. Gave them one application of B-52 (1/4 tsp per qt.) sprayed. Plants are looking like shit!! Lower leaves are yellowing (from edges) and droopy, growth stunted, with a little bit of leaf twisting..

My opinion is the nute levels are WAY too high.. especially with direct application to the roots. So, I swapped in a fresh reservoir today at 675 ppm with a ph of 5.6 and left the H2O2 out of the mix... I've also changed the cycle time to 45 sec. on, 6 min. off... I guess we'll see in a couple of days..

Does anyone have any suggestions for appropriate nutrient levels for aeroponics from veg through flowering? The HT article I used for reference, this dude was suposedly juicing his plants to 3000 ppm during flower. I say BS!

Peace,

Farmer Rich

I'm doing the same thing here's my log:http://boards.cannabis.com/hydroponi...hing-else.html

just a shot in the dark, but do you think it was too much h202? i haven't dipped my thumb into 'dro yet, but i've read of people using 1 Tbsp of 3% h202 per gallon of water.
i know 35% is supposed to be better because it isn't stabalized with whatever it is that stabalizes it at such diluted levels, but it's obviously much more potnent.

again, just a thought.


-shake

Hey Shake,

Nah, I don't think the H2O2 is the issue. Believe me, I did a lot of research and also talked to the AN tech support person.. For cure/prevention of root rot, 1 tbsp + 1 tsp per gal (1 tsp per quart). The other thing it does is help oxygenate the water (the extra O molecule is the only difference from water) and it also breaks down within a few days. The only bad thing about using H2O2 is if you have any beneficial microbes, it'll kill them along with the bad ones.

Farmer Rich

Hey Shake,

But I did remove the H2O2 from the equation today when I swapped the reservoir.. ;) so, I guess I was kinda wondering too..

Later, Farmer Rich

i got ya farmer!

like i said, it was just a thought.

you obviously have your sh!t together. and i'm sure you'll figure it out.


-shake

the person that wrote the article in HT is a foolitup member named stinkbud
the forum message that describes itis called Harvest a pound every 3 Weeks
started on 10-5-08 the post is in excess of 600 pages but you may find the info you need there www.rollitup.com Good luck:rasta:

Your nutes maybe just a bit high for that strain but I don't think so. What is throwing me off is the watering time. I think it should have alot more time in between on time sprayers. If the sprayers are pointed up and wetting the rootbal then they sound like they are overwatered.

In hydro or soil there is no such thing as overwatering. It is more a matter of duration of saturation. Almost any plant will die if the rootball does not dry out an hour in 24 hour period. This period can go longer but the chances for drowning become greater too.

I would suggest increasing your dry time till you see some droop and then leave that and increase your wet spray time. Say 15 minutes on and 1 hour off or adjust 10 minutes on 50 minutes off. You will find the right times for your setup. Tweak the system is what it's all about.

Hope this may help. We just had along talk about overwatering and what it really means. I understand now mistakes I have made. Let us know so we all can learn. I may want to setup your system one day.

I just saw this was a month ago. Hope you got it straight.