Need some experienced growers advice urgently

[giz2k14]

Hey my girl is 24 days into 12/12 and 15 days of actual flowering she's is in 20 litre pot of bio biz all mix she's being fed 1ml grow and 2ml bloom per litre of water total 6 litres when watering to get nice run off I do this every 4 to 5 days also she's under 600w hps this problem started right at the top of the plant on the main bud the leaf tips where yellowing from the tip in ward now I just checked her this morning and found all this yellowing here's some pics hope some one can help

 

[Silky Shagsalot]

i'd yank that main cola down below the others right now. i'da actually done it a couple weeks ago. your nute strength numbers seem a bit low. so you're in about a 5 gal. container. hows your ph?

 

[UncleBuck]

not sure what's causing your problem, but as an experienced grower i'd say your soil looks starving (and thus your plant).

water it heavily, wait 15 minutes, and water it heavily again. you should get tons of runoff the first time, and less runoff the second time.

then go back to your nutrient pattern after that. maybe even up it a little. i just ran the conversion and you are giving .6 teaspoons of nutrients per 1.5 gallons of water. i don't know anything about the brand of nutes you are using but that seems low.

 

[giz2k14]

i'd yank that main cola down below the others right now. i'da actually done it a couple weeks ago. your nute strength numbers seem a bit low. so you're in about a 5 gal. container. hows your ph?

what you mean yank it down and ph is in the 6.5 range well im using biobizz grow and bloom and i says use 2 to 4ml per litre

 

[giz2k14]

not sure what's causing your problem, but as an experienced grower i'd say your soil looks starving (and thus your plant).

water it heavily, wait 15 minutes, and water it heavily again. you should get tons of runoff the first time, and less runoff the second time.

then go back to your nutrient pattern after that. maybe even up it a little. i just ran the conversion and you are giving .6 teaspoons of nutrients per 1.5 gallons of water. i don't know anything about the brand of nutes you are using but that seems low.

im using biobizz gow and bloom bottle states 2 to 4ml per litre so what your saying is flush it yeah ?

 

[MidwesternGro]

It looks like a magnesium deficiency to me. I would use a tablespoon of epsom salts to every gallon of water.

 

[MidwesternGro]

Purple leaf stems and veins with yellowing usually indicates a magnesium deficiency.

 

[giz2k14]

Purple leaf stems and veins with yellowing usually indicates a magnesium deficiency.

hmm i gave her magnesium about a month ago and was reading that she can have another dose every 3 to 4 weeks but doesn't mag def start at bottom not the top ?

 

[MidwesternGro]

hmm i gave her magnesium about a month ago and was reading that she can have another dose every 3 to 4 weeks but doesn't mag def start at bottom not the top ?

Could be pH lockout. In my experience magnesium deficiency hits the entire plant at the same time. I would hit it with epsom salt in a 5.5 pH solution.

 

[MidwesternGro]

https://www.soils.org/publications/sssaj/abstracts/31/3/SS0310030390?access=0&view=pdf

An increase in soil pH from 5.3 to 6.7 significantly decreased the uptake of Mg by corn from soil treated with coarse and fine dolomitic limestone but in most cases had no significant effect on Mg uptake from magnesium sulfate. Total Mg uptake from fine dolomitic limestone was significantly greater than from coarse dolomitic limestone applied at rates of 15, 30, and 60 ppm of Mg to soil of pH 5.3 to 6.7, but was usually significantly lower than Mg uptake from magnesium sulfate, hydrated lime, or burnt lime. Very little difference in total Mg uptake existed between magnesium sulfate and hydrated or burnt lime.

 

[giz2k14]

https://www.soils.org/publications/sssaj/abstracts/31/3/SS0310030390?access=0&view=pdf

An increase in soil pH from 5.3 to 6.7 significantly decreased the uptake of Mg by corn from soil treated with coarse and fine dolomitic limestone but in most cases had no significant effect on Mg uptake from magnesium sulfate. Total Mg uptake from fine dolomitic limestone was significantly greater than from coarse dolomitic limestone applied at rates of 15, 30, and 60 ppm of Mg to soil of pH 5.3 to 6.7, but was usually significantly lower than Mg uptake from magnesium sulfate, hydrated lime, or burnt lime. Very little difference in total Mg uptake existed between magnesium sulfate and hydrated or burnt lime.

the soil ph has always been 6.5 range how would i get a solution down to 5.5 sorry im new to this see

 

[MidwesternGro]

the soil ph has always been 6.5 range how would i get a solution down to 5.5 sorry im new to this see

You need a pH test pen and some pH down solution or pH up solution to adjust your nutrient solution to the desired pH. I use coco coir hempy buckets so I adjust my nutrients pH from 7.0 (where it is out of the tap) with pH down until it reads 6.0.

If your pH is not correct you will suffer nutrient lockout because the nutrients are only available to the plant at a certain pH range. Cannabis likes acidic soil at a pH range of 6.0 to 6.5.

 

[MidwesternGro]

This is definitely a magnesium deficiency:

Note the purple veins and the yellowing of the leaf.

 

[giz2k14]

This is definitely a magnesium deficiency:

Note the purple veins and the yellowing of the leaf.

yes i can see now i had a mag def with this plant before but the yellowing leaf margins was lower leaves thats why was skeptical this time because it was top leaves and my ph is in the 6.5 range my solution is 7 neutral and run off is 6.5 but my tap water is really high without any nutrients in it so can i mix epsom salt with the nutrient solution or has it got be with just water ?

 

[MidwesternGro]

yes i can see now i had a mag def with this plant before but the yellowing leaf margins was lower leaves thats why was skeptical this time because it was top leaves and my ph is in the 6.5 range my solution is 7 neutral and run off is 6.5 but my tap water is really high without any nutrients in it so can i mix epsom salt with the nutrient solution or has it got be with just water ?

You should be alright if you mix it with the nutrients.

 

[Fultono]

This sounds like a question for Walter White.

 

[waterdawg]

hmm i gave her magnesium about a month ago and was reading that she can have another dose every 3 to 4 weeks but doesn't mag def start at bottom not the top ?

I did have a mag def (I think lol) and yes it started at the bottom and the veins on the leaf stayed green while the body turned yellow then rusted and died. I sprayed plant with epsom and it went away. Not so sure thats your issue. Plant nute issues are a bitch for me to identify, and Im a newb as well.

 

[giz2k14]

You should be alright if you mix it with the nutrients.

Thanks for your replys and your information I will give Epsom salts tomorrow and see if there's any improvement in next few days and if its worse ile know its not that thanks again

 

[Greenhouse;save]

So is it possible to foilar spray a mag solution straight on to the foliage.I think I'm suffering the very same thing but I have already watered mines(10 mins ago) so could I proceed and foilar spray?

 

[Greenhouse;save]

Feedback would b appretiated and sorry to hijack ur thread giz.