Drying yellowing bottom leaves

[Adam11]

Hi guys,

I have 4 autoflower strains growing organically in soil under 300W Mars HYDRO Led from which 3 are showing signs of yellowing dryingfan leaves with brown spots on the bottom part of the plant. The rest of the plant seems fine.
My run off ph is between 6-7 on all of my plants.
My source of feeding is guano tea spiked with chicken manure, worm castings, kelp, bone meal and fish emulsion.
I believe this is P deficiency but can someone please confirm this before I give it nutes as I am not 100%sure.
Or is this normal during flowering as the energy gets drawn away from fan leaves?

Thanks in advance fellows

 

[Cannaficiando]

My source of feeding is guano tea...

Hi Adam...seabird or bat guano? The former is high in N, whereas the bat guano comes in two varieties, one with high N (from bats feeding on insects), the other with high P (bats feeding on fruit and flowers). No sign of N toxicity showing on your ladies, but you could do with extra P during this stage of flowering.

I see the fan leaf problem often during my grows. It usually stems from contact with wet soil and is nothing to worry about if the rest of the plant looks healthy. It may also be normal draw down of the nutes stored in them. However, some of the experts around here have eyes that see what mere mortals can't, so wait for another opinion.

Good luck with the rest of the grow.

 

[Cannaficiando]

I've rotated your pic to avoid others getting cricks in their necks. :smoking:

 

[Waira]

..thanks Canna'!

--- Adam, the pH run-off alone offers little insight without knowing the pH going in,...a range of 6-7 tell me there's something wonky with those readings,...keep in mind, pH is a logarithmic scale, and the jump from 7 to 6 is a 10-fold increase in free H+! .... there is a calculation to be made, and more important, the run-off method is highly prone to measurement error; here's a link to an improved methodology if one must use this to get a reading-- https://www.autoflower.org/threads/...-for-run-off-testing-and-ph-estimation.41733/
--- organic or not , soil pH needs be monitored often; only exception I've heard of is with folks who have a well developed TLO type soil.... pH'ing your feed inputs is also wise,... Look into an Accurate 8 soil pH probe, which will measure the soil pH directly-- no more guesstimates! .....that said, since it's the lower, oldest leaves that are tip wasting, I'd say it's likely them getting tapped into for some mobile nute,.... I'm leaning toward P as well, given your plants stage of life, but a pH issue could be in play... Canna is spot-on with the poop P-K ratios, so let us know what kind it is, and at this stage, be careful with the high n sources-- that chicken poop and fish goo are both strong sources, the last thing you want during bloom,... right now, you want low N, and high PK #'s,...

 

[Adam11]

Thanks for your replies.

The guano I use for brewing the tea is a high P guano 3-15-4..chicken manure and fish emulsion is only there in small amounts.
I have been feeding them 1 time a week with this mixture.
What I meant with saying my ph readings are between 6-7 on my plants as all of them fall in to this range.
There is no massive difference in one single pot just a little here and there varing from plant to plant.
The water that is going in is ph 6.5 bottled spring water and the run off is 6.6 so no ph problem in my opinion.
I gave them a top dressing of guano yesterday... See what happens.
Thanks.

 

[Waira]

:smoking: Ahhhh, I see... yeah, only ones that are of potential concern are those near 7,... Fe is rapidly locked out there, and some of the other micro's not far behind,.... K is the only nute left that's lacking in the collective here,... P and K should be about the same during bloom, to fatten them buds up proper! Have you considered an organic PK booster? And speaking of micronutrients, Earth Juice Microblast makes a good organic micronute' supplement,... this one, with an eye to prevention; because many of them are immobile in the plant, and you're in bloom now, they can be a pain to correct! (foliar, arguably the best way to deal with micronute defc.'s, is more or less out now-- don't want residues and potential mold issues....

 

[Adam11]

Hey Waira,

The tea I Brew for feeding my girls contains unsulphured blackstrap molasses and liquid kelp as well which I believe are a great K source.
Do you recon its a micro lock out?
I had a look at Fe deficiency photos and they don't look too much like my plants.
I thought that liquid seaweed contains micros as well as the molasses.
I think next time I will buy some proper nutes and use only tea as a supplement....
Whats your oppinion on biobizz nutes?

 

[Waira]

... sorry mate, should have qualified this.... I don't see K or Fe defc. at all, it was just a heads up on potential things that might become an issue; I always aim for prevention if possible vs. cure! Molasses as a nute source is a bit of a mystery to me so far, in terms of how rich a source it actually is,... Ca, Mg, K and a little Fe are the most abundant nute-elements in there, and chelated too,...Of course, the sugars juice-up the soil herd big time, which in turn benefits the girls! .... Kelp is awesome stuff as well- And I'd say ditto, about how rich it is for the secondary and micro' nute elements,... your feed regime includes them often enough though, that I figure you have a cumulative thing going, staying equal to or ahead of demands,... I wouldn't rely of them for fixing a defc. though,.... As for PK ratios, when one wants to really fatten the buds up (beyond what base nutes can do), keeping plenty of P and K around is key,... don't want something like K to become a limiting factor, if not outright deficient,.... Roots Organics makes a nice PK booster (HPK it's called; not used it myself yet),... and I very much like General Organics BioBud as enhancer/hardener supplement, which I have used, and love the results! I'm low on the organics learning curve myself, and from what I see of my betters, it's clearly more difficult to achieve the same outrageous production that synthetics can... but many of us aren't in it for the yield, but the higher quality end product that organics offer, ay? I'm blown away by what some of our TLO guru's can do!.... but man, what a learning curve and process,...