Need DIAGNOSIS! Please!

i have several different strain growing and all are doing well for the most part. I have one Great White Shark who's growth has been noticeably stunted. The tips of the leaves begin to look rusty, and continue to brown and shrivel. These shitty leaves have worked their way up only on 2 of my plants, one of which is already over 4ft tall so I'm not as concerned. However, I would love to fix this Great White plant.
I know it isn't over fertilizing, I haven't feed it in over a week.
I know it isn't over watering, I have been strictly regulating the feeding.
These leaves started to occur during fertilizing, so I'm assuming it isn't under-fert.
What could this be? a Mag deficincy? I will post pics if needed but it's real simple, the ends of my leaves are turning rusty brown and the plants growth is stunted.
I've been dealing with a spider mite problem as well, but this has not affected any other plants in the same way. Any ideas? Please!
I'm thinking of trying some epsom salt to see if it is a Magnesium problem.

BUMP! help

Check your ph looks like its over 7. Could be a micronutrient deficiency or metal toxicity. How's your water?

Ph is good. Just checked it. I use purified water from the store when I water them, usually just calcium and sodium carbonates in it.

Try distilled water. Too much sodium bicarbonate (baking soda) can lock out nutes.

I'm guessing they didn't get to 4ft tall if your macro nutes like cal mg are off. Aluminum copper and boron can all be toxic. But more likely you're missing some micro nute. Try a new brand of fertilizer for a bit (with different ratios).

Right now I'm using Botanicare PureGrow, some organic shit I got from a local hydro store. I have been using moderate doses of these nutes and they had no prior negative effects on the plants. Any other suggestions?

Not really, I had the same thing happen in DWC with Botanicare hydro. I added a micro nute from a nursery with iron zinc boron and other trace elements and a bit of miracle grow. It seemed to help and the damage was confined to the lower leaves. I figured it was the cold temps I was dealing with but maybe its characteristic of Botanicare.

IGrowSnow said:

Right now I'm using Botanicare PureGrow, some organic shit I got from a local hydro store. I have been using moderate doses of these nutes and they had no prior negative effects on the plants. Any other suggestions?

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does not look like mag deficiency. looks more like a phosphorous overdose than anything else. see the pic

it is a deceptive problem, because it takes a while to show up, especially if your pH and everything else appears fine.

I would flush the plant with 3x the volume of water /soil with a new fertilizer, (very mild mix) like foxfarm grow big or general hydroponics maxigrow

My guess is that your "organic" fertilizer has some source of very slow release phosphorous that has taken time to build up, so everything seemed ok until now

and maybe that plant doesnt process phosphorous as well as the others

ooo i was having the same the same problem and i couldnt figure out what was wrong i was freaking out i couldnt figure it out i did EVERYTHING i thought it was calcium def. a mixture of calcium and water mix to them helped but wasnt the problem well the soil i had was very low in phos. and i didnt know so i changed the soil and havent had the problem since so that is most likely your problem i say change the soil or tweak your nutes

I'm having a really hard time deciding whether I should continue to flush the mother plant or whether I should try and add nutes to fix the problem. Any other suggestions?
My current Nutes are 3-2-4 and some of the ingredients are fish meal, seabird guano, etc.
What is the best way to add Phosphorous in a small amount and see if that helps the problem?

IGrowSnow said:

I'm having a really hard time deciding whether I should continue to flush the mother plant or whether I should try and add nutes to fix the problem. Any other suggestions?
My current Nutes are 3-2-4 and some of the ingredients are fish meal, seabird guano, etc.
What is the best way to add Phosphorous in a small amount and see if that helps the problem?

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I am saying you have a phosphorous OVERDOSE, NOT A DEFICIENCY

those organic ferts you mentioned are all released much slower than soluble nutes, hence the slowly toxic buildup.

I'd actually suggest you flush with water, then replace as much soil with fresh stuff as possible. Then get one of the ferts I mentioned - foxfarm growbig or general hydro maxigrow, and use a mild solution after your water flush (ie next watering)

right now the phosphorous is locking up your other nutes

they look hungry

So some people are saying too much, others too little.
I really am doubting it's too little, perhaps too much. However, how long will it take for a plant to recover? How long does it take to properly flush without over watering the plant if I'm using 5 galls?
I've uploaded a couple fresh pics. The best way I can explain the onset of this problem is that the tips of the leaves are turning rust colored and then into brown and crispy, accompanied by yellowing.
All advice is welcome and appreciated.
Thanks.

Bump... I went to the store where I purchased both my soil and nutes. Dude reccomended adding Cal Mag, so I've given the babies a small dose of some water with molasses. Should I foliar feed with molasses as well??

IGrowSnow said:

Bump... I went to the store where I purchased both my soil and nutes. Dude reccomended adding Cal Mag, so I've given the babies a small dose of some water with molasses. Should I foliar feed with molasses as well??

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I wouldn't. at a minimum, all that sticky sugar is gonna attract pests. at worst it could make the buds unsmokeable, full of sugar. you dont want to smoke sugar, you want the plant to break down the carbs itself.

I'm interested to see if the cal mag works. if not I say try pure water flush. you have nothing to lose and it will recover pretty fast. flushing IS overwatering. you want water running out the bottom, taking the salts with it

What's the best cheap way to add Phos? IE. Without buying another bottle of fert.

Phosphoric acid from General Hydroponics is used to lower PH. Go easy with it. Also, I was told that Botanicare strips out the micro nutes from their formulas. So you must replace or loose the plants.

Take a deep breath - relax - now lets look at what you have. Browning and crispy leaves - check. Stunted growth - check. Droopy leaves - check. This is likely a chemical balance issue attributed to having too much of something and/or causing something else to be locked out. I think Ian is right - looks like an overdose of phosphorous to me.

You sure that pH is in check? (did you measure the runoff or the pH of the stuff you were adding?) I find this to the problem more often than not. What do you know about your soil blend? Lets start there to see what your base is and what you are adding to it. I would not recommend foliar spray because you need to remove the chemicals out to return to proper levels - not add more back in.

Whatever you do, don't compound the problem by overreacting and trying a bunch of things at once. Make a decision and see it through before you evaluate whether that helped or not. Leeching is the "in case of emergency, break glass" type of reaction. If you are not seeing any progress with returning to a normal non-nutrient enriched feeding regiment, then go this route and flood the soil to leach the salts and nutrients away. You will want to pass through 3x the volume of your containers over a single watering with pH adjusted distilled or RO water with near zero TDS (slowly if possible).

What are your temps like in there? Do you have a heater near the plant?