browning of middle leaves

[snapfrost]

I am growing in rockwool in a modified flood and drain system with a 20 gallon reservoir feeding 8, 3 foot trays. they are lit by 2 1000 watt hps. My water is 0 ppm from a RO unit. my nutes are GH, i am using 5 ml of micro and 7.5 ml of bloom per gallon of water. my feed solution ph fluctuates between 5.6 and 6.0. the plants are from seed and they are approx 2.5 weeks old. the ones showing the browning and spotting are strictly the bogglegums.
the rockwool was soaked and rinsed per grodans instructions.



here are a couple pics, please let me know if i am missing any information.

 

[CannabisFox]

read this thread yesterday.... still have no clue whats going on. but it might be something with the rockwool.. maybe to wet.

what rh temp do you have in the room? and what ec does your water have with nuts?

 

[snapfrost]

The rh in the room is 58%
I have a bluelab meter and the ppm in the reservoir is 460, I can check the ec for you tomorrow if that will be helpful. The pumps come on once a day to water the rockwool slabs. The trays are on an angle so they drain and It seems like the high side is usually dry and the low side is overly wet.

 

[CannabisFox]

maybe they shouldnt stay on a flat ground but a little above.. that the water can drain more equally.
and maybe the rockwool should be covered?

 

[snapfrost]

The trays are on milk crates and one side is about an inch higher to drain the water back into the reservoir via gravity. As for the rock wool not being covered... I really screwed up taking the out of their packaging. Do you think the rockwool being naked could be the problem with the leaves browning? The plants have pretty much stopped growing and it is getting a good bit worse

 

[snapfrost]

The only thing else I can come up with is, maybe it has something to do with the RO water. I have used the recipe before with my tap water without issue but this is my first experience with RO.

 

[CannabisFox]

Ok. Personal I did never use those slabs. Since I'm growing hydro im into DWC. So much about my experience.

Your plants have some serious issues. Hope your grow is not too big so that the loss you already have and that eventually get bigger will not turn out "that" big after all...

1) PH & EC are both in range. (so we dont have a problem here)
2) One side of the rockwool is always more wet then the other one. (doesnt matter because every bubblegum genetic is afflicted)
3) It is not your first grow you have experienced some successfull grows before this one....
4) The main difference is that you now use RO water. Correct?

I would check some infos about that genetic if they are more the high or low nut absorber.
Then I would check if especially those plants could have some root issues.
It looks to me like special def of some macronutrient(npk) or a lockout.

If you have the possibility to feed those plants different give 'em fewer nuts and check the signs. Although its more likely a def I would start the check for a lockout...

Btw I'm using RO water by myself and its working perfectly.

Another guess would be that your Ro water gets fucked in some way...maybe use the old tap again on some plants to check this out?

 

[mysophilia]

Your RO unit is pulling all TDS out of your H20 source... Just looking at your feed schedule you need to add Cal/Mag since its being stripped out of your H20 source... Cal/Mag is very important for the plant to keep growing... This is what veg phase is for, splitting of your cells and supplying the right amount of elements for this growth..

 

[snapfrost]

cannabisfox
you are correct as the only difference i can think of is the Ro water.


ok, heres what i am going to check for and do today.
1) make sure the roots look to be in good condition.
2) I am going to empty and sanitize one of the reservoirs, and refill
it with 1/2 strength nutes (230 ppm) along with a tsp
of calmag per gallon pf water.

if this does not seem to halt the problem in a day or 2 then i am going to switch back to my tap water.

 

[Headbandf1]

Looks to me as a Phosphorous Def according to the leaf diagram, second would be a Mag def.

Also if you don't use them already i would highly recommend coco mats a layer or two under your cubes ( help to get air to the roots during the drain. otherwise they sit in the drenched rock-wool. Also you're missing your flood and drain scheduled - frequency.

 

[guest456mpy]

+1 Cal/Mg for the reasons stated.

 

[snapfrost]

Headbandf1, you say "you're missing your flood and drain scheduled - frequency."
can you elaborate on this? should i be feeding them a few times per day instead of just once? i was just under the impression once was enough until they are a bit older since the slabs are staying so wet.

i will look into the coco mats as this sounds like a good idea.

 

[Headbandf1]

Most growers i know that do flood and drain at the minimum Flood 2 a day and keep the flood for 45 minute.But others do 2 during dark and 3 times during lights on but only flood for 15-20 minutes.

If i were you i would do 1 dark and 2 lights on and that shouldn't push it to hard to cause you problems but hard enough for very good results.

But 1 a day is deficient.

 

[snapfrost]

here are some updated pics from today.
today i have noticed the afghan x skunk have started showing browning/spotting like the bogglegums.

 

[RubeGoldberg]

+1 Cal/Mg for the reasons stated.

Also supporting this,

You aren't getting massive pH fluctuations normally attributed to un-buffered RO water, but you still need to be using it in your scenario. Also you're not running the grow part of the GMB solution, which contains a good portion of the magnesium your plant needs.

I don't have a problem with the lucas formula, but a lot of the 2 part flora recipes are based off of the idea that nute labels are accurate as far as content of the bottles.


double check your pH meter as well, grab some cheap litmus paper or drops and test your TAPWATER (not ro) against your digi meter

 

[Hydro-Soil]

Save some money... skip the cal/mag as I've never needed it with the nutes you're using.

bump up your feed. 460 is too low. Go 6/9 or 8/16... either or will do the trick and all this dumb stuff will go away.

YOU DON'T NEED CAL/MAG WHEN USING GH NUTES THE LUCAS WAY AND R/O WATER. Thanks
You may occasionally (and I stress occasionally) run in to a strain that would BENEFIT from a tiny amount of cal/mag but it won't be stressed like you're seeing.

Quit starving them and give them what they're wanting.

Stay Safe!

edit: I LOVE that someone marked this post as not being helpful. Dunno where everyone that knows Lucas went but..... doesn't seem to be anyone but myself around at the moment. So sick and tired of people pushing cal/mag for the lucas formula.... especially peeps that don't have any experience with it. Last year I would have been one of several folks preaching the same thing... Now I seem to be a loner. *shrug* I guess we need more peeps that actually do research again.... all the info is here on the boards folks.

 

[snapfrost]

Hydro-soil
The girls are only 3 weeks old and between 6-9" tall. If you are certain they can handle it I will crank the nutes up to full strength tomorrow on 1 res and see if that works. I would really hate to switch back to tap after buying the RO unit so I am willing to try anything once.

 

[Hydro-Soil]

They can handle it...

One of these days I'll get around to publishing my "Speed Sprouting" method. Seed to Seedling in full strength nutes (Lucas+R/O) in about 10 days.

Stay Safe!

 

[Hydro-Soil]

...

 

[snapfrost]

thanks, if anything you have given me confidence in the fact that i am not killing them by giving them full strength ferts. I gave them a good shot of 6ml/9ml micro/bloom about 30 minutes ago. it was right around 1.1 EC. I will report back tomorrow on their condition