lsd scrog, leaves yellowing

[JimmyTheJaw]

anyone got a clue on what this is, water is always ph to 6.5, feeding bio bizz nutes (all of them) about to check soil ph, i will update later when i have the reading, they are 29 days 12/12

barneys farm lsd

 

[kevb123]

mine were doing that!
read a few posts and said could be nute lock or lack of p

 

[JimmyTheJaw]

just done a ph test and i would say it is about 7 (im using the drops and barium sulphate method

 

[IVIars]

Does biobuzz have calmag in it?

 

[thrash4ever]

Does biobuzz have calmag in it?

No it does not!
I forgot/neglected the advice of a user by the name of BunnyFace who advised it is extremely light on Ca and Mg.
Top Max only has trace amount of MgO and zero Calcium. I am using Grow, Bloom and Top Max.
I can't believe they do not sell this shit with a label on it stating the above.
Maybe they assume everyone laces their soil with dolomite lime!?

Not sure about the problem.
Are you sure you are adding sufficient trace elements including the heavy metals?

 

[JimmyTheJaw]

not sure, i thought it was an iron def, just wanted other opinions

 

[thrash4ever]

Calcium and Magnesium - check if the full range includes any of this beyond trace amounts. I know Top Max has MgO in trace amounts but it is no way near enough.
If your pH is balanced and you have sufficient amounts of trace elements (like Fe and Zn) I am guessing it is a Magnesium deficiency. In fact I am almost certain of this.

 

[NEVER OUTGUNNED]

i say lack of nitrogen. the leaves are fine, they just lack color.

 

[JimmyTheJaw]

when i last gave them nutes i put in a bit extra of the bio grow just incase this was nitrogen, i dont want to add nitrigen because they are 5 weeks into 12/12, i thought that it was a big no no to add nitrogen in late flowering???

i have been using epsom salt with every second watering aswell, i have been using 1 table spoon to every 10 litres of water, didi not want to over do it with the stuff, maybe i should add a small amount more next time?

 

[BBYY]

Can we get another photo in more of a natural light. It looks like the plant is under a spectrum of 2000k and its hard to see the colors of the plant.

From reading what you say and looking at this easily found chart its possible the higher pH you reported can be causing a lock out.
What method are you using to measure pH? Are your tools calibrated? Talking in means of measure the nutrient water, not the soil. If the water is at 6.5 thats on the high end of the prime zone, and then if your not that accurate at your readings who knows if its really at 7, or higher.
View attachment 1556439

 

[JimmyTheJaw]

i am using a digital meter for the water and nutes, i calibrate it with two different buffer solutions every 2-3 weeks, i tested the soil with stuff i got from the garden center, you add the drops of liquid and one scoop of barium sulphate to one ml of soil, you then compare the colour to the colurs on the chart, i now water the plants with a ph of 6.0 to try and bring the soil of the ph down a bit

its not as if this yellowing is happening quick, the leaves in question started yellowing about 2 weeks ago, i will update the pics tonight when the light comes on, there is no way i can get the plants into natural light, they are in a scrog

thanks

 

[thrash4ever]

Tip: use flash photography as soon as the lights go off to get a better shot.

 

[JimmyTheJaw]

thanks i never thought of that, but i will do it the opposite way, as soon as they come on tonight

 

[JimmyTheJaw]

here is the pictures. i took them just before the lights came on, could do with some answers asap cause these plants need watering, so i could do withan idea of what to add and what not to

thanks

 

[JimmyTheJaw]

plants looking worse by the day, i have flushed them with water, just hope that helps

thanks

 

[thrash4ever]

Sorry, been away.

My guess is: calcium, magnesium, and potentially iron and phosphorous have been locked out, and/or you have created toxic soil conditions by not regulating the pH (burning the plants or creating element antagonism).
You need to accurately measure the run-off pH of your flush in order to get the soil to the optimal conditions. Those analogue tests only give you a rough idea of what soil pH is like. Post-flush do a very light feeding schedule.

Summary:
- measure your water's (flushing) pH
- measure the run-off (take multiple readings; first stage and last drips of run-off perhaps?)
- compare all the results
- when you are happy with the run-off readings, introduce a light feed (of course, pH-balanced)
- if you need to raise the pH of the water/feed you introduce to your soil there are many products available
- once pH of the soil is stabilised only ever introduce pH on or very near to 6.5.