Why are my leaves discolouring?

fumaganja

fumaganja

Well-Known Member
Hi guys,

I'm 4 weeks in to flowering, and I'm noticing quite a few my fan leaves are turning yellow, and even a couple have gone 'crispy' at the end. It seems to be getting worst the further in ti flowering we go. Maybe needs another trim?

I'm growing in soil and my ph is always between 6.0 - 6.5, using grotek nutrients. Temperature 21-23c and 45 - 50% RH when lights are on and approx 18-19c and 51% RH when lights are off.

I've got 2 600's, one with standard reflector and one is air-cooled, I've done it this way to regulate the temperature. Extractor fan and intake fan always on, 500w fan heater on when lights are off, and humidifier on when its needed.

Thanks
 

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StareCase

StareCase

Well-Known Member
Do you use any calcium/magnesium supplements - such as Botanicare's Cal-Mag - in your feeding regiment?
 
StareCase

StareCase

Well-Known Member
For 4 weeks flowering, there does appear to be a little too much yellowing. A couple of your pics showed yellow "meat" with the veins still a darker green. They appear to be Mg deficient.

I had the same yellowing after flower stretch. It appears that the recommended 1 tsp./gallon of Botanicare's Cal-Mag was still not giving my ladies what they needed. I was willing to sacrifice the crop as an experiment to see if stepping up the Cal-Mag would help 'em or hurt 'em. Here is what I tried:

Feeding (given per plant every Sunday AM):
  • 1 Imperial Gallon ( ~4.5 liters )
  • 1 tbsp. of Cal-Mag
  • 2 tsp. Fox Farm Tiger Bloom (any bloom fert will work)
  • 1 tsp. Epsom Salt (warm a little water up separately then dissolve the Epsom Salt and add back)
  • pH the water to 6.5

Water Only (given per plant every Tuesday & Thursday AM):
  • 1/2 Imperial Gallon ( ~2.25 liters )
  • 1/2 tbsp. Cal-Mag
  • 1/2 tsp. Epsom Salt
  • pH the water to 6.5

The yellowed leaves turned green again within about 14 days. Some of those leaves that are too far gone won't come back.
 
P

piratebug

Well-Known Member
What strain are you growing? Anyhow... you said you weren't giving them any ca/mg, so I would work on getting that added to your base because lots of strains need a steady supply of ca/mg and the ones that don't won't get hurt by the added supplements. Also as a side note... adding a ca/mg supplement to your base is one of the best things you can do from the start because believe it or not, a lack of those (2) supplements makes up most of the deficiencies that I have personally seen in my 40 years or growing! The supplement mix I use is, 5ml or 1 tsp GO ca/mg+ plus I add 1/2 tsp epsom salt per gallon of water from day 21 up until the ending of week 7 of flower!
 
fumaganja

fumaganja

Well-Known Member
StareCase said:
For 4 weeks flowering, there does appear to be a little too much yellowing. A couple of your pics showed yellow "meat" with the veins still a darker green. They appear to be Mg deficient.

I had the same yellowing after flower stretch. It appears that the recommended 1 tsp./gallon of Botanicare's Cal-Mag was still not giving my ladies what they needed. I was willing to sacrifice the crop as an experiment to see if stepping up the Cal-Mag would help 'em or hurt 'em. Here is what I tried:

Feeding (given per plant every Sunday AM):
  • 1 Imperial Gallon ( ~4.5 liters )
  • 1 tbsp. of Cal-Mag
  • 2 tsp. Fox Farm Tiger Bloom (any bloom fert will work)
  • 1 tsp. Epsom Salt (warm a little water up separately then dissolve the Epsom Salt and add back)
  • pH the water to 6.5

Water Only (given per plant every Tuesday & Thursday AM):
  • 1/2 Imperial Gallon ( ~2.25 liters )
  • 1/2 tbsp. Cal-Mag
  • 1/2 tsp. Epsom Salt
  • pH the water to 6.5

The yellowed leaves turned green again within about 14 days. Some of those leaves that are too far gone won't come back.
Click to expand...
Thanks! I'll give it a go
 
fumaganja

fumaganja

Well-Known Member
piratebug said:
What strain are you growing? Anyhow... you said you weren't giving them any ca/mg, so I would work on getting that added to your base because lots of strains need a steady supply of ca/mg and the ones that don't won't get hurt by the added supplements. Also as a side note... adding a ca/mg supplement to your base is one of the best things you can do from the start because believe it or not, a lack of those (2) supplements makes up most of the deficiencies that I have personally seen in my 40 years or growing! The supplement mix I use is, 5ml or 1 tsp GO ca/mg+ plus I add 1/2 tsp epsom salt per gallon of water from day 21 up until the ending of week 7 of flower!
Click to expand...
I'm growing critical. Thanks for reply, I'll give it a go!
 
fumaganja

fumaganja

Well-Known Member
I have managed to take some more leaves to study under the microscope now. I thought I may of had spider mites or something but I cant find any insects.

Looking at these leaves I would agree it's a shortage of nutrient. Do these photos help you understand what it is anymore?

The concern that triggered the thought of mites was one little bud growing brown pistils as you can see in photo. But again, I cant see any signs of infestation
 

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