What determines yellowing fan leaves more? Genetic Plan or Medium?

[duderonomy]

What has a greater influence on a plant with regard to the plant turning a fan leave to yellow?

Is it the specific stage (week) in flowering or the amount of nutrients in the medium? generally speaking?

I speculate, that even with a 20 cubic mound of super soil, a plant will still turn its leaves yellow at a particular time.

What is a plant doing, in a healthy plant, when it is selectively turning leaves yellow, seemingly draining the green from it. (when not in hydro being specifically flushed)

I was thinking that the yellowing was related to amount of nutrient value in the medium; but I have same cultivar with same medium in different sized containers that got flipped into flower at different times. So, all mediums are same age but yellowing fans leaves are occurring in stages. Some are very restrictive sized container like Air-pot(TM) compared to a 10 gallon plastic pot.

It seems not to be based on medium running out of nutrients, I think is what I am getting at.

I'd like to hear the experience from folks with loads more experience.

I'd like to get direct experience with a hydro only grow and watch what happens when the EC is dropped to nothing for a period of time.

Cheers!

 

[Chunkypigs]

cannabis fan leaves close to the main stem will yellow out and die off on their own naturally at a certain stage and it's different in each plant. I have 30 + different clones running and it is different for each one.

nutrition levels are going to affect when it happens but they will all do it, more or less, as flowering happens.

wide leaf - narrow leaf varieties will behave differently too.

I have about 30 yards of soil in this bed, it's pretty "Super", and still have it going on...

look at the difference in these 3 at the end of veg, Headband, Durban Poison, SSH, left to right.

OG Kush yellowing now.

another Josh OGK that was stressed and stunted from transplant yellowing harder than others...

some cookies strains will stay very green until it frosts here, Mac1 is always very green until the bitter end in my soil.

many differet things that can make leaves turn yellow but it's not always a sign of a nutrition problem, it happens naturally as the plant matures both in veg and in flower, strain dependent and also happens from mineral issues or fungal problems.

 

[duderonomy]

Thanks Chunkypigs for the most informative answer I could have expected.
Seems you touched on genetics, health, medium, stage of flower.
[EDIT: and mineral issues or fungal problems]

I have run just 1 cultivar for more years than I like to admit due to how long it took me to listen to the plant and stop following directions online. With the pH finally near perfect for the plant while also using peat/soil, I no longer have red color streaking on the surface of the stems and petioles; stems as hard as a board and solid. Early on, I once had an anomaly of hollow stems. That was before Bitcoin.

With things dialed in, I added some variables with container size and type: traditional 7 and 10 gallon pots vs #3 and #12 Air-pot. Also supplemented outdoor light for an additional 2 weeks on a group. I wasn't sure it was working but now it is clear that it did have some effect.

In flower stage, I have an airpot #12 and a conventional 7 gal ahead of another group. I started noticing that the plant seemed to be making the decisions. A correlation to "juice in the medium" was not as consistent as I would have expected based on what I was seeing.

Maybe the amount of light is also a factor determining how fast they are metabolizing. As one Air-pot #3 is still very green and it may be because it maybe a little shaded by a larger plant. Yet in the same group a 7 gal is already showing yellowing (which is a lot more noticeable than the airpot#3). So maybe the air#3 one was not running as hard as its neighbor due to sub-optimal position with respect to the sun. It still gets a little direct light but full-length like some neighbors.

Does a higher metabolizer of the same cultivar flip and progress into flowering faster than a healthy specimen metabolizing slightly slower due to less light?

Thanks for sharing what's up, CP! Super helpful!

 

[Creeperpark]

The plant will sacrifice older leaves for needed water or nutrients. When a plant doesn't have enough water it starts with the firstborn leaf in the order they are born and transfers the water or needed nutrients to where it's needed. The bottom leaves are the first to go and if the plant doesn't get enough water the yellowing will work its way to the top of the plant. Use your finger to always feel the soil daily to keep up with the plant's needs.

 

[duderonomy]

The plant will sacrifice older leaves for needed water or nutrients. When a plant doesn't have enough water it starts with the firstborn leaf in the order they are born and transfers the water or needed nutrients to where it's needed. The bottom leaves are the first to go and if the plant doesn't get enough water the yellowing will work its way to the top of the plant. Use your finger to always feel the soil daily to keep up with the plant's needs.

hey Creeperpark.
You express the prioritization quite well! Thanks for the reminder about the water!
The "born-on date of those fan leaves" thing may be why I see the large fan leaves yellowing, in order, up the trunk. passing branches with green growth.
Nice clarifying observation!