Alaskan Ice - First DWC - Got a deficiency I believe.....HELP!

K this is my first foray into Hydroponics and I've run into a problem. I'm running a DWC, 14L, with a 6" netcup, hydroton, grodan rockwool, and 3500cc hagen airpump. Growing a Feminized GHS Alaskan Ice from seed.


What does this damage look like? 2 older fan leaves (5 leafs?) have been displaying deficiencies. It's been getting worse and spreading (very slowly).
I've looked at a lot of pictures online and can still not figure out what this is.

It started as a very minor single burn on the tip, then brown/copper dots started forming. Afterwards leaves started turning yellow in the same spots. The newer fan leaves (7 leafs?) are beginning to show signs of the same damage, not on the tips, but little brown/yellow dots (mid pic). I lifted up the reflector material I have blocking light from getting into the tank and there is a small green spot of the grodan cube. Has been dry since rooting.

I've been considering pruning these 2 damaged leaves. What do you think? (Also, will pruning kill the node it's been feeding? I usually don't prune out of fear of shocking the plant)

I originally thought it had to do with the AN Voodoo Juice I gave it in the previous feeding, but further investigating revealed a high PH (approx 7.0). Thought it might be a calcium/Magnesium deficiency caused by a PH lockout.

I flushed it for 24H, then put nutes back in at a lower strength than the previous feeding in PH 6.2 water. Looks like the problem is furthering itself 3 days later. Think I should have flushed it longer?

I also am considering it might be the foliar spray, which is PH 5.8 water with AN Grandma Enggys Fulvic and Vit B1 (Thiamine Mononitrate) added. Thought maybe undissolved solids were burning the leaves under the light.

For Nutes right now, I am giving it:
GH Maxi-Gro 1.10g/L
AN Fulvic 2.5ml/L
AN Bud Candy .75ml/L (probably shouldn't give it eh?)

Other Nutes I have on hand:
AN SensiBloom A+B
AN Carboload
AN Big Bud
AN Bud Blood
AN Voodoo Juice

Temps
Day (lights on): 24-27c
Night (lights off): 22-24c
Water: 21-22c

Any help would be appreciated and will rep those that help. I'd hate for something to stunt this plant. Only 3 weeks into veg and filling out nice IMO (4 weeks since germ).

As soon as I can get this fixed, I'm planning on putting this under the screen and begin training it as I'm going to scrog at 12". Height is only 8.5" right now.
Will also be going under a Hortilux 250w HPS powered by a lumatek ballast for the remaining veg period depending on how things go.

BUMP.

No one has any idea? Come on, rep for help

Someone help this man out- he's given every bit of info needed for someone smarter than me to tell him what the problem is and how to fix it.

mag def

Episom salt. I would go light 1/2 tsp gall

so your ph is at 6.2? you should lower that to about 5.8, that could be causing the mag def lockout

Yea 6.2 is the reccomended ph for soil not dwc.

Epsom salt for mag deff.... like the guy 3 posts above me stated.

K thanx for some replies.

Are you guys sure it's a magnesuim deficiency? Going by the pics in: http://www.420magazine.com/forums/problems-pests-disease-control/81275-cannabis-plant-pest-problem-solver-pictorial.html - It actually looks more like the first picture that describes a late calcium deficiency.

I will be getting some epsom salt in the morning regardless. Did some research and it seems worth having on hand. I assume walmart would probably carry it.

Lowered the PH to 5.5-5.8 and we will see how it goes. I also added GH Maxigro (.25g/L) to the foliar as it has Calcuim and Magnesium in its listed ingredients.

Will the damage repair itself in time or should I prune those leaves off?

Ok ok, Mg and Ca is what your lady is lacking. That foliar is a perfect start. Add that stuff in when you are watering. I would try to just pick up a bottle of Cal-mag, mostly Mg and Ca (because the plant takes them in about evenly) and other micro nutes as well. Cal-mag should be used if the water you are using has a low ppm from the start. What type of water do you use?

Leaves are fucked, but leave them until they are completly dead and pretty much come off on their own.

i think your PH is off. good going to flush it out for awhile. i'd suggest lowering your PH and keeping a close eye on it to keep it below 6.0. i prefer 5.8 myself but unless your have a digital meter , it is kinda hard to maintain a strict, tight level like that. if ya dont have one, go spring for a PH meter. it'll come in handy for sure.

id go light on the epsom salts. i personally dont think you have a deficiency at all. AN work like a champ when growing alaskan ice. i've been on aslaskans for quite some time and i prefer it. the smoke is amazingly good for my style. ..grown it DWC style, soil, even outdoors over a long summer period. i've cloned the living piss outta her and always have a good success rate.

your nutes selection is good, your set- up looks good so dont stress.

i would suggest thatyou veg for like 2 months time though if ya can hold on that long. you'll thank me. your yield will double. and if ya LST them it'll help yield as well. never top! the colas grow very beatifully. do you know which pheno you have?? i only keep the short fat girls that look more indica dominant. the sativa looking ones tend to grow tal and stringy at times. .
my yields for vegging a months time and 2 months flowering under 400 HPS gives me 2.5 oz. dried per plant. i usually do four at a time though under the 400 HPS. thats DWC set -up with advanced nutes line up of nutes and supplements. i use a room fully lined out in mylar as well, 4 walls, roof and flooring covered. no light escapes.

i'm not the alaskan guru or anything like that. take the advice though and try it out.

deviouslikeyou said:

i think your PH is off. good going to flush it out for awhile. i'd suggest lowering your PH and keeping a close eye on it to keep it below 6.0. i prefer 5.8 myself but unless your have a digital meter , it is kinda hard to maintain a strict, tight level like that. if ya dont have one, go spring for a PH meter. it'll come in handy for sure.

id go light on the epsom salts. i personally dont think you have a deficiency at all. AN work like a champ when growing alaskan ice. i've been on aslaskans for quite some time and i prefer it. the smoke is amazingly good for my style. ..grown it DWC style, soil, even outdoors over a long summer period. i've cloned the living piss outta her and always have a good success rate.

your nutes selection is good, your set- up looks good so dont stress.

i would suggest thatyou veg for like 2 months time though if ya can hold on that long. you'll thank me. your yield will double. and if ya LST them it'll help yield as well. never top! the colas grow very beatifully. do you know which pheno you have?? i only keep the short fat girls that look more indica dominant. the sativa looking ones tend to grow tal and stringy at times. .
my yields for vegging a months time and 2 months flowering under 400 HPS gives me 2.5 oz. dried per plant. i usually do four at a time though under the 400 HPS. thats DWC set -up with advanced nutes line up of nutes and supplements. i use a room fully lined out in mylar as well, 4 walls, roof and flooring covered. no light escapes.

i'm not the alaskan guru or anything like that. take the advice though and try it out.

Click to expand...

5.8 is a horrible ph for hydro. Do you even have an idea of what nutrients are taken up at what ph??


Between around 5.5-5.8 you are barely getting shit. Needs to be above or below that, and your fine. But your ph, should always fluctuate if you want to be giving your plants all the nutes they need. The difference between 5.8 and 6.2 is not going to cause his problems.

Ok water PH was actually 5.8-5.9. Water I have been using is city drinking water, which I tested with a hard water equivalent of PH paper. 1 out of 4 boxes turned color, so I assume it's low ppm. Water is always left out in a container for 24 hours to let chemicals out. If anyone knows the PPM of Calgary drinking water, let me know plz.

I am using Grotek Ph paper, tuned for a range of 5.5-8. I thought about getting a Hanna PH meter, but I'd rather wait till I can get one of the expensive models that monitors PH, EC, ppm, and water temp. I'm going to be keeping a closer eye on PH levels for now on.

Added some epsom salt to the mix at a strength of .25tsp/g and will see how it goes. Will possibly go out tomorrow and pick up some AN Sensi Cal Mg Bloom.

Not 100% sure what you mean by pheno, but from what I've seen, I consider the this plant Indica dominate. Plant is short and stretchy. 10.5 inches so far. I will add a pic taken from the side later to this post when the lights go on.

Devious, I will consider the 2 month veg. I have a box being built right now, dimensions are 24x24x60. I'm concerned about how I'm going to ventilate but I'll figure it out. Hope to have it finished with a screen by tomorrow as I do plan to scrog/lst. Screen will be placed where the plant's height is 12". How long I veg will depend on how long it takes to fill the entire screen.

I am vegging this plant under 150w of CFL's (2x42w, 3x23w, 4 in 6500k, 1 in 2700k). Do not take my comment about switching to the HPS light as me saying I'm doing a 1 month veg. One of the reasons I am going to switch from CFL to HPS after a month in veg is because I do not believe CFL's can adequately support the plant once it gets to a certain height without spreading the bulbs around, which becomes complicated. Plus the light spread is horrible without a reflector or a box.
I know a 250w Hortilux HPS w/ a lumatek ballast will be capable of doing a better job, regardless of the spectrum, plus I'm sure the plant will love the extra lumens (38000-41600 lumens, depending on lumatek claims of 20-30%). A hortilux bulb should give me enough in the blue for the veg period right.

So far, everything looks fine except those 2 leaves. The amount of spots on the other leaves hasn't changed.

1 thing I've noticed that has changed is that I now need to add a liter of water to the mix every 4 days. This alaskan sure loves to drink water. My root growth has exploded since the flush after having voodoo juice for 1.5 weeks. That nutrient f**ken rocks and makes me consider for my next grow, a DNA sharksbreath (might do a grow journal), that I also purchase AN Piranha and Tarantula to supplement the VJ. After the VJ, I'm thinking my 5 gallon bucket isn't going to be large enough for the flowering period, or I'm going to have to forgo giving it another dose at week 3 of flowering .