Hey there, just checking in - how're your plants doing?
Just thought I'd mention, I'm a newb on RIU too - and a bigger newb to MJ cultivation (and RIU) I'm in third week of veg on my first MJ grow
Just wanted to agree with you on some points - it looks like your humidity, the cleanliness of your room and your careful inspection of your plants wouldn't be the likeliest environment for molds, fungus or pests...
Here's a succinct
link to problems & diseases. I know you probably read something similar to this but it is a pretty good starting point. Anyone of these sound like they could possibly apply to your problem.
Brown/Purple Spots and/or Dark Green Leaves on Stunted Plant
This is generally a sign of phosphorus deficiency. You may need to add more phosphorus to your water or you might have a PH imbalance.
Brown/Tan/Pale Spots Throughout Leaves
You may have a phosphorus deficiency or you may have contracted a pest. Refer to the section on pests for more information on detecting and removing a pest infestation.
Yellowing Between Leaf Veins
This is likely a potassium deficiency. Add to your water or correct a PH balance. Potassium can also be locked out by salt buildup so if your PH is correct you may try a flush before adjusting nutrients.
Older Leaves Yellow From the Center Outward, Leaf tips brown progressing inward, pale new growth
Look to trace element deficiency for these problems. Magnesium and Calcium are likely culprits. You can add a bit of dolomite lime to your water (1 tsp/gallon) or add a supplement such as cal-mag, or cal-max, or similar. As always with nute deficiency your problem may actually be a PH imbalance.
Also found this little salient factoid from
here:
1) N, P, K, Mg and S are considered mobile: they can move up and down the plant in both xylem and phloem.
Deficiency appears on old leaves first.
2) Ca, Fe, Zn, Mo, B, Cu, Mn are considered immobile: they only move up the plant in the xylem.
Deficiency appears on new leaves first.
How long has this all been going on? How long since your first & last flushing? Maybe if we retrace your steps we could shake something out...
I know Nitrogen flushes out the fastest. Perhaps you have a small P (or K) overload and it's just taking a little more time to leach out? Your leaves look nice & green to my eyes - I wonder if that indicates that perhaps this is an indication that your plant has just reached the point of having a bit too many nutrient salts and consequently P (and possibly other nutrients) are getting locked out? honestly, given all the information you've provided - that is the hypothesis I feel most confident in.
As to a micro nutrient deficiency, I have really soft water, PPM of 90. I'm watchful of my Mag-Cal levels and am watching to see if I may have to jump in with an additive just in case I don't have enough... Just thought I'd throw that out there. Diagnosing is doubly hard by the fact that deficiencies and overloads often look the same (and, just for fun, they sometimes look like pest infections too - bonus round!)
Another slightly more informative blurb on Phosphorous def/toxicity & how that can effect other nutrients.
Deficiency Symptoms
[FONT="]Slow growing, weak and stunted plants that may be dark green with older leaves showing a purple pigmentation. Since P is fairly mobile within the plant, deficiency symptoms initially occur in older tissue.[/FONT] Deficiency Effects
[FONT="]Will seriously harm various processes associated with energy storage and transfer. It will effect root growth and bud development. Poor seed development and poor fruit quality and size may result. [/FONT][FONT="]The deficiency symptoms can mask other nutrient deficiencies such as nitrogen and potassium.[/FONT]
Symptoms of Excess
[FONT="]Excess phosphorus is manifested by micronutrient deficiency, with iron (Fe) and zinc (Zn) first affected. Excess P can induce potassium (K) deficiency.[/FONT]
This seems to apply: your plant growth as become stunted - fallen behind the others, was a week behind in flowering, the other leaves look almost blue-green to my eye, well fed. Your PH is fine for P absorption (looks like your PH is absolutely perfect for soil). You are feeding with every watering (could cause build-up?) - even though BioBizz Bloom is
slightly (very slightly) lower in P than other nutrient concentrations - I don't think this is possible to be enough to cause a deficiency this severe. The crumbling leaves, the older leaves going first, the stunted growth and all the rest mentioned - I'm with you, I think it's indicating a P deficiency (possibly a micro deficiency instead of or in addition to) which seems it can only be due to a salt build up as your PH is fine. It could be salt lock-out as you are feeding with every water - how long since the last & first flush again? How long do results from a flushing take to manifest? I would assume immediately and it's just a question of using enough pure water to do the job. This seems the likeliest unless it is a micronutrient deficiency which is likely also caused by build up as I read the BioBizz Bloom package and it specifically lists many micronutrients in it's formula. My best guesses. I'm starting to become nearly as curious as you are about the cause of your troubles. Still, it bugs me - why just this one plant?!?! So frustrating.
As I said before, perhaps it's a general salt build up locking out the P or the Mg, Ca, etc - & needs a good flushing to work it's magic. Maybe the bone meal AND the P in the BioBizz are too much for this specific plant. For soil I've always heard to use 3 times the volume of the soil in the amount of plain water used. To be followed by a reintroduction of the nutrient solution to correct the deficiency. I have heard you're not "supposed to" feed soil with every water - but it's clearly working for the majority of your plants and this isn't your first grow. Maybe this one is a little weak, a little more sensitive. (I feel a tad silly/sheepish writing these things to you, a much more experienced grower who very likely knows this and other things I've mentioned, but perhaps they will help a newb or shake something loose in your mind - troubleshooting is often backtracking & going back to basics, right?)
I just hope you don't have some complicated, chain reaction problem like the PH level is loading the soil with insoluable P, which is interfering with Mg or Fe uptake or some such) That's got to be on the top of my worst plant nightmares.
Please, let us know if you figure it out - we're pulling for you man. For real. I hope you will keep us updated and let us know what ultimately happens, whether the issue is resolved or not.
OFF TOPIC: I've figured out my problem: Thrips!
Miserable, wretched, evil thrips...
Who knew a little bug could cause such an intense mixture feelings from vengeance and righteous anger to indignation and loathing in someone who considers herself a pretty well adjusted person, all over a bug... I guess I'm just really into this hobby. After much research (up all night, of course) I'm using permethrin spray & sterilizing/cleaning the room to take care of it as the infestation and damage are too far along to wait for beneficial predators to suppress it. Given the emotions I apparently have tied to my plants - the surprising amount of affection I bear them including the regret when one dies/get sick - it looks like Reefer Madness was right: MJ has clearly made me insane. Warn the public!
But it's a real fun, satisfying obsession if you have to have one - fun fact that compounds the weirdness of my devotion to my plants: I don't even smoke, ever! Just can't anymore. But my fella does. And I do so love the smell, the care and the alien beauty of the plants...
. Give fungus, thrips, pests a quick search on this site, see if your problem dovetails with the whole pest/fungal rotting thing. Also, I read that nutrient deficient plants are more susceptible to these problems (if your problem is pests) and that can make dealing with it a trifle more delicate as you have a weakened plant with a parasite making it weaker. I can't imagine your plant's nutrient deficient - your other leaves are so green and healthy otherwise. And the dead giveaway to me seems to be what kaspa35 alluded to - the fact that the decay isn't symmetrical or all of something or another (like all the fingers dying back from the tips) - it's spotty, indicating your plant is being attacked/blemished in certain spots. I'll look around, check my books and if I find anything, I'll edit this post or add another. Again, best of luck to all.
The problem is it's slowed down on the growin' so I can't tell if new growth is good or not..
