Severe Nutrient Burn?

OK so here is whats up. After 2 weeks of feeding my plants 1/2 the dosage of Fox Farm grow big and big bloom, I upped the anti to full dosage, (maybe 1 tsp under) I gave this to all my plants, and the biggest one, which is about 3.5 ft tall, is experiencing severe nute burn.

Its going from the bottom up, the leaves are yellowing with black spots, and then dying and falling off. Every day more leaves up it are yellowing and burning. I have given it two feedings of plain phed water, 2 gallons and then 4 gallons. (Its in a 15g pot.) It seems to be getting worse! The others are barely burned, nothing like my big pride and joy!

What should I do? Is there anything I can do to save my big momma? It is outside, in a soil grow, in a green house. Still in veg cycle for atleast a month. What can I do???

You prob need to flush the hell outta it with more water. Thats a big ass pot its in.

So say I give it 15 gallons of water tomorrow, would that save it hopefully?

Schwag Bag said:

So say I give it 15 gallons of water tomorrow, would that save it hopefully?

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They say to flush 3-4 times the size of the pot if that makes sense..But that would be like flushing it with 60g of water which I think is way to much. Go with what you think will work.

the big bloom i dont think you have to worry about because it's so low in npk. they also claim on the bottle that you cant burn with it. i made close to the same mistake. my plan was to use around half strength but i made the mistake of listening to some idiot i know that told me to go full strength with the grow big. 2 of my plants got burned bad. one to the point where i think the roots were damaged cause the whole plant turned yellowgreen. i just flushed them by putting them in the bathtub and watered them a shit load of reverse osmosis water. the water running out of the pot was greenish but eventually turned clear with traces of dirt. on one the buds are a lot smaller, the small leaves by the buds are severely curled and the fan leaves are spotted, discolored, and curled. there other yellow/green plant is strangly doing almost as good as the healthy ones now. i think you will be fine. i would flush use shit load of water then leave it so the soil dries out. your roots may be damaged and a bit slower taking in water and you dont want it to be moist for too long cause your roots need oxygen. being moist for too long can also promote mold growth which could further complicate things. after it dries you can probably add a small amount maybe like 1 tsp/gal of big bloom. it may help repair the roots if damaged and make up for any micro nutrients if lost during the flush.

It doesn't sound like nuteburn, unless that biggest one is a different strain that the rest? Different strains, have different fert requirements. If they're all the same, it would be the smallest plants that would be effected first,(nuteburn) if they were all given the same fert, mixed at equal strength. Not the biggest ones. Are the upper fan leaves dark green and curled, or claw-like? Dark green with burnt tips? Hmmm....it's really hard to say without any pics, so, take those words with a grain of salt.

No all the upper leaves are green and healthy. The yellow/black burn is progressively moving from the bottom leaves up. I just flushed with 10 gallons of water. The smaller plants are exhibiting the same signs, the very bottom leaves are crisping up at the tips and turning yellow. Im prety nervous im gonna lose my plants . Could it be heat stress? They are in a greehouse and its about 95 degrees outside, I have a fan in there and the vents open.

What was the runoff PH? Didn't check it, did ya? I'm guessing your soil is going acidic, from decomposing, due to moisture. It's very possible in those size pots, because they take a long time to dry out, when supporting a plant that small.(for that size pot) Since the soil is still wet, I'd run another 5 gallons or so through them, except, with some lime added this time.

I had a similar problem once, except on a smaller scale(smaller plants, in 5 gallon pots). I flushed them with lime, then threw them on 12/12(within a couple days), and they lived happily ever after. The 'stretching period' boosted the plants' size enough to process water faster, due to their increased root mass, and they never had another problem with PH.

What do you 'PH adjust' your fert-mix to?

I have no idea what any of that means. Im an outdoor grower in soil. If you look at my other posting in marijuana plant problems(dont know how to link to it) its titled "The problems my plants are having" you can check out the pics I took today.

^I assumed that since you were in a greenhouse, that it wasn't any different than an indoor grow. Hmm.....basically, I was saying that your soil might be staying wet too long, and getting acidic, as it decomposes. 15 gallons, is an awfully big pot for a 3.5' plant, and would take awhile to dry out.


Anyhow, my main question is....what is the PH of the fert/water mixture, before you give it to your plants? Do you adjust it, or just use it, as is? If you do adjust it, what number do you shoot for?

Okay, just took a look at your pics, and they don't look as bad as I was thinking. A little droopy, but the overall color look okay. It looks like there's little white specks all over the foliage. Is that correct, or is that just the way they look in the pics?(hard to tell) If so, take a look under your leaves, because it could be a spidermite infestation. I hope I'm wrong, but figured I better ask.

I was going to say that the yellowing was normal(older leaves die, as the plants get mature), but, then saw the damage near the top. IDK man, if it isn't mites, I'll have to think about it for awhile.

I do adjust it, and I usually get it to around 6.0. Basically till the water is that bright yellow in the ph scale. I think youre right about the water taking a long time to dry out, it seems like the soil stays moist for a long time. I looked under the leaves, didnt see anything. The leaves start off with getting burn black spots and yellowing, then they develop into extremely black at the tip and upwards toward the middle of the leaf and the rest yellow. Would acidic soil cause this? Does that mean my plants are molding? What can I do?

Yep, the acidic soil can do that. Here, scroll down to the PH section, and do some reading.... http://www.icmag.com/ic/showthread.php?t=11688

Also, I stated that lime would be helpful in your situation, in my prior response. Check it out, think about giving it a try. Yeah, it'll get the soil soaked again, but'll be worth it, once it starts to dry out. It'll bring the PH up, and stabilize it, holding it in the acceptable range,(approx 5.5 - 7.0 for soil) longer.

Ok I guess I will treat it with lime. How much lime are we talkin though, like one lime wedge squeeze per gallon of water? Also, it looks as if most of my plants are suffering from this acidic soil, they all take a long time to dry out. Should I treat all of them with the lime?

LOL, I guess I should've been more specific. I wasn't talking about lime, the fruit. I was talking about dolomite lime, which is crushed limestone, in a powdered form.(it also comes in pellet form, so make sure you get the powder) It's also rich in magnesium and calcium, and will help prevent any of them from going deficient. Treat them all, it won't hurt them, even if it doesn't help your problem(if it happens to be something else causing it, other than PH).

haha Alright cool, so just put a little bit of powder for each gallon huh? I haven't given them any nutes in over a week and a half. The leaves at the bottom just all keep turning really black at the tips to middle and yellow. Hope I can stop this spread of death

^Add 1 tbsp of lime, per gallon of water. It doesn't have to be exact, just in the ballpark. Also, ph adjust your water/lime mix before you add the lime, not after.

Wait, what do you mean ph adjust my water/lime mix before I add the lime? Wouldnt that be just water then?

Also, I have attached a pic of some leaves that fell off today. I looked under one and I did see a small, black, spider like bug with a small web. I looked under other leaves and didn't see any other bugs. It's probably just the acidic soil right?

^What I meant, was that if your water needs the PH adjusted, adjust it before you add any lime. After you add the lime, there's no need to check the PH, because it'll be waaaay high.


That big you found, sure sounds like a spidermite. They spin tiny webs too, so you better take a close look, just to make sure, because spidermites can be a nightmare. Hopefully, it's just a PH problem.

ok #1. you dont feed the plant the bloom solution till you swich it to blooming. and 2. you only fertilize the plant once a week. where you flush befor you feed to get all the old fert out of the soil.

that being said.

after a flush you need to add diluted silution to the final flush cuz when you run all that water thru it zaps the nutrients, so after being nute burnd, the plant will suffer form nute deficiency unless the final run thru is w/ a very diluted solution...