Help! N-tox at low nute levels?

[Dhude]

12 Skunk x afghani. 10 days from rooted clone, under a 400w. Temp 80f.
5" square pots, GH cocotek mixed bricks (rinsed, and cal-mg treated prior to planting).

Feeding daily to runoff, GH micro & bloom, at the Head/Rez 1:1.5 ratio.
Very arid climate, plants transpire alot and I generally have to run weaker nute mixes. Current feed is 2ml Micro/3ml Bloom/3ml pH Down per gallon, yielding about 1.0 EC (starting tap about 190ppm @ 0.5), pH 5.8

Now, the problem is, plants look under fed. Even on the mothers. Lime greenish, and what looks like ongoing Mg def. But, if I bump the concentration up, I get classic Nitrogen toxicity.

I'm Stumped. Any input appreciated. I've been mainly been a dwc guy, only toyed with coco a bit before now.

 

[~fvk~]

Sounds like they could need more than one daily watering/feeding. Are the pots pretty dry by the next day? What size pots are your mothers in? Can you throw up some pics?

 

[MobbDeep]

try using a foliar feed of epsom salts to prevent and remedy mag defienciency..i truly doubt that is a n deficincy..as most nutes,ESPECIALLY one like g.h..has planty n-p-k..try the epson salts man..and "classic" n tox..afghanis is a pure indica,and pure indicas are known for a very dark green color,which can be mistaken for n toxic...i had a ak48 plant that was VERY dark gree in veg..

 

[~fvk~]

Foliar feeding for magnesium in coco is far from remedying a mg deficiency. It's not getting to the real problem at hand. N toxicity is characterized by ram's horn, and your plant doesn't have to be dark green to get it. When your plants are "root bound" in coco, they turn pale from not being able to take up water along with the nutrients in it. They will also get burnt by any salts that aren't assimilated by the plant in the medium before it dries out. It's a viscous cycle at the least.

 

[Leviathan]

i dont know how arid it is by you but if your in the desert maybe u should make your nutes weaker and apply more often.. but with coco u dont need to rememdy by external foliar feeding, u up the ph to 6.0 im told for like a week if its a mag deficency, id say your underfeeding unless u have rams horns.. then your overfeeding. any pics.

 

[Dhude]

FVK, thanks.

Mom's in 1gal. About 20" tall. Pots don't dry out in a day, still damp, but noticeably lighter next day.

Foilar feeding for a problem is treating the symptom rather than the actual problem. Not saying I don't or won't do it, I'm saying that a dialed system shouldn't need Mg foilar. Going to transplant soon, we'll see what the rootbound situation is like.

When I said "classic n-tox" I mean the 90-degree downward bend on leaf tips, turning to full-on ram-horn if not flushed and backed off the N for a bit.

 

[Dhude]

Runoff pH=6.2, ec=1.6

 

[Hash Man]

youre not feeding them enough... when i first started growing in coco i misidentified a toxicicity with underfeeding... and let me tell you, the minute they got a good dose of nutes, they took off... personally i have found rez and heads formula to be weak on my plants... i think a few people on here have done no runoff grows with weak ppms and been sucessful... i use rez's recipe like an a plus b... and i add ppm with additives...you should at least be using 6/9 ... not 2/3.....

 

[Dhude]

I had that thought Hashman, but I actually started off with the unmodified 6/9 on a 2' tall established mom and it went full-on ram's horn within 2 days. When I backed it off to 2/3 that particular mom looked very happy for a while...dark green leaves, no signs of defs.

That was feeding every day or every other day. I'm beginning to think at that size, in a one gal pot, I need to make the feed schedule more frequent...maybe 2x to 3x per day, during lights on mainly for oxygen exchange rather than actual nute needs. My dwc rez maxes out at around 1.7 EC during mid flower, and most of the run goes around 1.2-1.3 EC anything higher and they burn. So I'd expect to have to run similar strengths in coco. I did bump up my 3ml Bloom to 4ml for feeding last night, leaving the micro at 2ml. That will up my Mg a bit...and back to the "lucas" ratio.

Will be transplanting today most likely, tomorrow at latest and report back on rootbound condition.

 

[~fvk~]

That was feeding every day or every other day. I'm beginning to think at that size, in a one gal pot, I need to make the feed schedule more frequent...maybe 2x to 3x per day, during lights on mainly for oxygen exchange rather than actual nute needs.

That's what I was thinking. You can go a long time with large root systems in small containers with coco, but you'll need multiple feedings daily to keep the roots healthy and happy. You could transplant them, or just increase the feedings and see how it goes from there. I'm sure you know you're going to need to divide what you're feeding them now, across however many feedings you'll increase to.

 

[Leviathan]

i was useing 8 ml of flora nova bloom(thats the lucas dose)and was getting defficiencies, i uped it a little and over night they looked near perfect.

 

[Dhude]

On a side note, I'm stoked to have solved my other "issue". Plants were looking slightly overwatered, droopy the last several days. In the past, I've used my old dwc airpump/stones as a sort of mixer in my watering can, but mainly for mixing, not really to oxygenate the water. I was counting on the regular watering/feeding sucking new O2 down to the roots, and the natural air holding properties of coco to prevent "overwatering" (which is really just a lack of O2 to the roots, no such thing as "overwatering" per se).

Well, I added air stones to my can for 10min before watering yesterday and within an hour they went from droopy to raised leaves and happy. Now to get nutes dialed. I will always bubble my mix prior to feeding from now on, lesson learned.

 

[~fvk~]

Good to hear man, let us know how everything goes. So were this other issues an unrelated problem, or were they the plants in the 5 inch pots?

 

[Dhude]

Yeah FVK, it was on all the plants, but a still a separate issue from the defs as far as I can tell...but...

bubbling the nute mix raises my pH a bit, and the last 3-4 feeds have been at about 6.0, at 1:2 micro:bloom. That extra bloom (the Mg source in GH 3 part) and the higher pH seem to be solving the def issues.

New growth looks much better, lush and green and has noticeably taken off since the change. Thanks for the help buddy, looks like I'm good for now.

Oh yeah, on the transplant...yeah the moms were pretty rootbound. Am now adding AN's JumpStart (seaweed extract and humic) to the nute mix for the first week after transplant to promote rooting into the larger pots.

 

[~fvk~]

Hmm, sounds like overwatering was the main culprit then. My bad, they both show similar symptoms sometimes though. Good luck and have fun.