Yellowing leaves - og kush auto and cheese by dinafem

[Ivana2309]

hi to everyone,
this is my first grow and first topic here and thanks to the admin for accepting me.
My problem: i have searched through the lot of forums for related issue and i received different answers but i didnt resolve anything
The leaves on this plant started to yellow at the end second week of vegetation before i transplanted it.

Here's information about the plant:
og kush auto (dinafem) :

og kush3.
18 days old plant

https://ibb.co/k2v6d5

box: 23" x 19"- x 62"

light: dual spectrum cfl 300w
distance from light 5"

induct fan 183 cubic cm per hour
passive intake airflow 11" x 11"
plant height 6"
soil & temp:

https://ibb.co/bPn8rQ
https://ibb.co/iy4XJ5

watering, not feeding, twice a week, when cup is light or soil well dried

on the second plant cheese by dinafem

https://ibb.co/hB1wd5

i notice that lower leaves also started yellowing too but this plant seems growing better.

Plants are in the same box.

----------
Strain: cheese by dinafem & og auto kush by dinafem

Age from Sprout: 18 day

Soil : janeco light mix by ATAMI: NPK:12/14/24, ph 6

watering Twice a week: when i see that soil is about 2" dried

PH of water: 6ph: i have ghe test kit, a drops sistem

conductivity: 45ms/m

nutrient : alga grow by plagron

Indoor
Light system: 300W cfl dual-spectrum, plants 5" from light

Temps; Day: 25celsius Night:21Celsius

Humidity; 70%

nutrient: alga grow by plagron: Ec i dont know, is 100% bio

Ventilation system; Yes

Humidifier: Yes
Co2: No:

Any advice?

i know that this question has been asked many times but maybe you can help me
I thank you in advance for every answer and sorry if I made a mistake asking this

 

[GoatCheese]

watering, not feeding, twice a week, when cup is light or soil well dried

Hey.

It could be that the soil dries out abit too much, so try watering them more often.
It's good to let the soil dry out every now and then, but if it happens too often, the plants start yellowing.

 

[Ivana2309]

ok...thanks,
after i googled a bit i realized that maybe the problem is in ph. I set up water-ph according hydorponic table which proper ph value is a bit lower than soil

https://ibb.co/ecNGT5

and after that i added alga grow that dropped even more ph in my wtaer and soil.

maybe, i dont know...this is my girst grow.

i need a digital ph tester to eliminate ph problem.

 

[Ivana2309]

sorry for off-topis question...how do you add a links at the bottom of your post?
i know that is somewhere under personal account settings bit cant find
thanks

 

[GoatCheese]

Sometimes pH-problems are the symptom, not the cause. So because of under watering the acidity of the soil may increase .

Have you measured the pH of the run-off water? pH 6 shouldn't be that badly off, but you may want to aim for the recommended pH 6.5.

Also, some Ph-down/-up products are buffers, meaning you don't have to use them every time cause they stay in the soil for a while buffing the pH.

Different nutrients are also best used by the plant in different Ph-levels, so it may be good to allow the pH to change abit, within reason of course.
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You need a certain amount of posts to be able to create a signature (links, pictures etc) i think.

 

[Ivana2309]

I stopped dropping ph and added alga grow, ph is about 6.5 because I do not have a digital ph tester
We'll see ... I think maybe the light is too close even though I do not feel the heat on my palm
I flashed and fed them tonight

- cheese is ok but it seems too small...only 5" after 19 days???

https://ibb.co/kjSQMQ

- auto og-kush as you can see the end of the leaves start to curl up but is 7" tall

https://ibb.co/e4xvo5

thank you very much

 

[GoatCheese]

The way i use GHE's pH-down is; i use it about two times in a row, then the third watering i leave it out, so that the pH of the soil doesn't go too down, cause it is a buffering kind as i mentioned.

We have fairly stable tap water here so i don't follow the pH that much, but sure it is more important if the water pH around your area isn't very stable.
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Plants react differently to over or under watering. Try to keep the soil abit more moist from now on, but it is good to let the pot go fairly light once a week. But don't over-compensate and water them too much.
Easy does it.

 

[Ivana2309]

The way i use GHE's pH-down is; i use it about two times in a row, then the third watering i leave it out, so that the pH of the soil doesn't go too down, cause it is a buffering kind as i mentioned.

water around my area is very stable, so i'll try to follow your advice for sure.
thanks