Yellowing leaves at start of flower cycle

[aliceklar]

Hi all - can anyone advise on what might be going wrong with these plants? Some necrosis on the leaves, older lower leaves yellowing and dying, red stems, and yellowing between the veins. Is this nitrogen deficiency? Magnesium??



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Varieties are Blueberry, White Rhino and Thai Stick, all MSNL regular seed. I'm growing in 75% compost with 25% perlite, in 2.5 or 3 litre pots, top-dressed with gravel, sand and DE to deter fungus gnats. Last time I repotted them a couple of weeks ago I added half a teaspoon of blood fish & bonemeal to each one. I've just started feeding them with very dilute tomato feed. Previously all they got was an occasional foliar spray with seaweed extract. I've been watering with BTi and nematodes recently, which has got the gnat numbers right down. I'd been going very light on watering because of the gnat problem, but wondering if now under 12/12 and a more powerful light they are getting thirsty??

They were previously under a mix of crappy unbranded COB LEDs, but a few days ago I flipped them to flower under a new SF1000 spider farmer LED quantam board. Lights 12-14" above plants.


Peace!
AK xxx

 

[TanzanianMagic]

Hi all - can anyone advise on what might be going wrong with these plants? Some necrosis on the leaves, older lower leaves yellowing and dying, red stems, and yellowing between the veins. Is this nitrogen deficiency? Magnesium??



.[URL=https://www.icmag.com/ic/picture.php?albumid=82200&pictureid=2004902&thumb=1]View Image[/URL] [URL=https://www.icmag.com/ic/picture.php?albumid=82200&pictureid=2004901&thumb=1]View Image[/URL] [URL=https://www.icmag.com/ic/picture.php?albumid=82200&pictureid=2004900&thumb=1]View Image[/URL]



Varieties are Blueberry, White Rhino and Thai Stick, all MSNL regular seed. I'm growing in 75% compost with 25% perlite, in 2.5 or 3 litre pots, top-dressed with gravel, sand and DE to deter fungus gnats. Last time I repotted them a couple of weeks ago I added half a teaspoon of blood fish & bonemeal to each one. I've just started feeding them with very dilute tomato feed. Previously all they got was an occasional foliar spray with seaweed extract. I've been watering with BTi and nematodes recently, which has got the gnat numbers right down. I'd been going very light on watering because of the gnat problem, but wondering if now under 12/12 and a more powerful light they are getting thirsty??

They were previously under a mix of crappy unbranded COB LEDs, but a few days ago I flipped them to flower under a new SF1000 spider farmer LED quantam board. Lights 12-14" above plants.


Peace!
AK xxx

They need more airflow.

It looks like mildew. Also,the pots are likely already too small for the plants. If you want to avoid nutrient deficiencies, bigger root systems (more phophorus) in more soil is the way to go.

 

[Paddi]

Hi aliceklar - And welcome to ICMag


Oveall your girls look ok.
If they were mine, I would´nt worry
You treat them well.
Maybe they would love a little more food.
And bigger pots.

Whats your plans?


P

 

[aliceklar]

Thanks Paddi and TM

I thought it might be something to do with the size of the pots... sigh... My plan is to use a fairly small cupboard space (2' x 3', plus a smaller veg alcove) to squeeze in lots of different varieties, so I can get a taster of several different types of weed. All I can buy here is generic superskunk, and I want to try something different... I dont want to maximise plant size or yeild - I want to get a little bit of several different kinds. And then maybe i can narrow it down a bit... But I will definitely up the feeding!

TM, you have eagle eyes! The white dots you can see on some of the plants are not mildew - its where I spilt some diatomaceous earth, and also dust that drifted over from where Ive been making a hole in the wall of the veg area to install a filter and fan. I didnt think it would drift over the other side of the cupboard...

Longer term I'm setting up a perpetual grow, and have just lightproofed a veg area with the weaker LEDs in it, so I can have 18/6 and 12/12 going at the same time. I'm an experienced gardener and amateur plant breeder, but have not grown cannabis for nearly 25 years - just one time when I was a youngster and a friend gave me some flourescent tubes and a handful of seeds... (cannabis was a gateway drug to gardening.. .lol). I'd love to do seed saving & experiment with breeding.. but want to get the basics sorted first!


AK xo

 

[ElGato]

looks like a little over-watering and you may need to back off on the ferts a tad


just my 2c



mj

 

[trichrider]

have you tried CalMag?

 

[Creeperpark]

You have a cal mag deficiency.

 

[imakandi]

Sorry dont want to be that guy
But there's no cal mag deficiency
You Have Ca deficiency Or Mg Deficiency
Not Both Together

I Very Noob, Maybe More Food

 

[GMT]

As said, bigger pots, but your light is too close. If you want smaller plants, run from clones not seeds and start them flowering when much smaller. Tomato feed isn't ideal either.

 

[aliceklar]

Thanks everyone - have raised the light a bit and will feed. A few of them have just shown their balls, so I will be taking them out of the flowering area & will repot the remaining girls to make the most of the space. Noted GMT re clones - will bear that in mind in future
Peace AK x

 

[f-e]

That lightening between the veins, making a chevron pattern, might be Mg. It's usually moved out of the middle leaves to support growth at the top. The leaf will usually feel odd. Like a wash board. Defra suggest half a gram of Mg per liter of soil is good for similar plants. Which you would put in with one hit. While hydro feeds add about 0.035g per liter. You know.. roughly. I have seen fast responses when applied as a foliar spray, but it's so long ago, I only remember it seemed a very hot mix imo.

Mg is a major component, who's lack could be why you are loosing leaves at the very bottom to nitrogen deficiency. Though frankly, a bit of drop into flower is quite normal, and N only slows flowering anyway. The leaf was never much use down there, as anything but food reserves. Let them go. The plant has better things to expend energy on, than supporting old growth, no longer in the light.

There was a single leaf, looking terrible, but I'm going to ignore it. You can't trial two fixes at once, it confuses results. Besides which, it might of just been a random bout of metal poisoning. Compost can do odd things, and it seems to of passed.

 

[Chappi]

Probably rootbound, plants hate skinny jeans.

 

[f-e]

I like canna terra food. Their terra substrate isn't meant to work without it. Though it can at a high pH and a low demand. Everything is in the terra food. It even works well in coco. Proving it's complete balanced formulation. Such a food (of which I know no other) might be ideal if you expect your pots to become totally exhausted. It turns into a hydro grow of sorts. Then the pots are amply sized.

Epsom salts is Mg. Well Magnesium sulfate, just about. Sulfur doesn't push other things out, so a little extra doesn't hurt.

 

[aliceklar]

I like canna terra food. Their terra substrate isn't meant to work without it. Though it can at a high pH and a low demand. Everything is in the terra food. It even works well in coco. Proving it's complete balanced formulation. Such a food (of which I know no other) might be ideal if you expect your pots to become totally exhausted. It turns into a hydro grow of sorts. Then the pots are amply sized.

Epsom salts is Mg. Well Magnesium sulfate, just about. Sulfur doesn't push other things out, so a little extra doesn't hurt.

Thanks - will try out Epsom salts. and yeah... am realising that such small pots is effectively turning this from a soil to a hydro grow (ie soil is just a medium and once exhuasted Ill need to supply all the nutes..)... not what I had intended, but ya live & learn eh.

 

[Tonygreen]

Before you go adding anything check the ec and ph of your run off.

 

[aliceklar]

After 1 week of feeding and increased watering

After 1 week of feeding and increased watering

Repotted the Thai Stick into a much bigger pot (from 2 litres to 5.6 litres), incorporating a teaspoon of bonemeal / fish blood and bone into the new soil. Roots growing vigorously into the new soil.

Watered all plants more frequently (they were all dry - i had been holding off water too much in an attempt to combat the fungus gnats - but the nematodes have effectively stopped them now, so i am increasing the water). Also feeding with dilute tomato feed and maxicrop seaweed extract. This seems to have had a positive impact - new growth is much greener and fresher looking, with less yellowing between the veins, and some of the older leaves have also greened up some.

I realised that my tapwater is very hard, with 300ppm of calcium carbonate, and alkaline, so switched over to watering using collected rainwater instead a few days ago. Again, this seems to have had a positive effect.