This looks like light bleaching but I'm not sure. Any advice?

[Son of Hobbes]

I really do believe that light bleaching "cooking" the top of the plant causes damage, consider it a form of topping.

I disagree with this; it's not a form of topping at all. Topping is removing the main shoot on the central stem of the plant (which causes the plant to bush out with many side shoots instead of focusing on the central main shoot (stalk.)

Here's some food for thought on light bleaching:

Plants and algae have a love/hate relationship with light. As oxygenic photoautotrophic organisms, they require light for life; however, too much light can lead to increased production of damaging reactive oxygen species as byproducts of photosynthesis. In extreme cases, photooxidative damage can cause pigment bleaching and death, a phenomenon all too familiar to anyone who has tried to move a houseplant outdoors into full sunlight.

What are your temperatures in the tent? Do the leaves feel dry or crispy at all?

namvet or muddy; is it possible that the peat and worm castings is too much of a hot mix for the new seedling? Might be stressing it out?

 

[Muddy]

namvet or muddy; is it possible that the peat and worm castings is too much of a hot mix for the new seedling? Might be stressing it out?

It's possible the soil could be a bit hot but from what I can see in the picture it looks like the yellowing on the leaves is starting from the center and working out. If so, then it's bleaching. 16" was a little too close for a 300 watt LED on a seedling, especially if that's 300 actual watts. Something in the 20 - 24" range would probably be better.

 

[Kaiju]

Thanks a lot guys

I think it could be a combo of both the mega worm and the light being too close maybe

I've got it to around the 30" mark now

It was the perfect circular shape of yellowing which made me think it looked like a sunspot like from a magnifying glass

Temps 70-80 and no they feel fine

 

[Kaiju]

Ok so update of pics here

My conclusion is definitely the plagrons mega worm even through it said fantastic for germination they haven't been specific to how to germinate with it so
As you cans dee there's some new brown spots and slight whitening which I think looks like severe over fertilisation

What ya recon? Poor girl

 

[Gonzo]

How much Mega Worm have you put in all together? 10-20% is recommended.

I

 

[Kaiju]

Lol it was all mega worm

I think I misinterpreted their statement because after potting them I read up on using worm castings from seed and everywhere was like unless the seeds are fertiliser hungry it won't grow and I was like shit hopefully plagrons mega worm is different.

Another amateur grower mistake

 

[Kaiju]

hmmm so

potted a seedling in a multipurp soil which i know has been tested and works fine
and day number 2 the weird starting of the yellowing again -

im starting to think i have bad airflow as everything else is fine

obviously plants need good airflow to survive - but does any one know any signs or symptoms of plants lacking good air flow ?

 

[Kaiju]

This to me looks like heat and light stress

My reasons for thinking is one of my other new seedlings which has just come out of propigator has started showing the yellowing Inbetween leaf veins

I'm thinking heat and air maybe as I've heard the more co2 you have the more the plants can handle heat so maybe that's why my concoction of failure continues

What do you think of the pics?