Early cotyledon yellowing - sign of poor root development?

[ItsAllMedical]

My current batch of seedlings has had a hard time and I lost a couple to damping off. The survivors are hanging in there but a bit behind in growth.

I've noticed that some of the cotyledons are completely yellow and ready to fall off despite not a lot of top growth. Others still have green cotys and are ready to put out a third set of true leaves.

Since I've got to pick a pheno to keep (assuming they all make it) is it safe to assume that this is an early sign of good root development & strong genetics - that the plant hasn't had to pull everything it can from the cotys at this early stage? Or is it as much down to chance as genetics?

 

[One drop]

Some pics would help you got flying blind . Od

 

[ItsAllMedical]

Some pics would help you got flying blind . Od

Some pics would help you got flying blind . Od

So pic 1 vs. pic 2 is a good example of what I mean. Same age, same strain. Seedling 1 has completely depleted its cotyledons. Seedling 2 has better growth, a thicker stem and green cotyledons. None have roots emerging on the bottom yet, but I'm guessing seedling 2 has superior root growth.

My question is whether this is likely to be a genetic trait or whether seedling 1 is a survivor of pythium or similar, or yet to succumb. And then, if some seem more susceptible to fungal attack, is this too genetic? They're all in the same medium.

 

[One drop]

Normal ? But your doggy avatar is so cute I think there doing fine nota fan of the bark in your mix it’s causing Nitrogen draw down taking N from the plant as it compost down and the paper pots are a how can I say not the best option when are you potting up .

 

[ItsAllMedical]

Normal ? But your doggy avatar is so cute I think there doing fine nota fan of the bark in your mix it’s causing Nitrogen draw down taking N from the plant as it compost down and the paper pots are a how can I say not the best option when are you potting up .

Thanks, yeah I really wish I'd waited and ordered some quality seed raising mix. We don't have much available locally but it definitely looks like it was a mistake. Didn't know that re the bark/nitrogen, cheers. There should be plenty of N in that mix to compensate though.

The pots are peat and I'll be putting them into soil in large fabric pots in my tent; was going to wait until I saw signs of them outgrowing those pots...pretty scared of stressing them out further or inadvertently overwatering after the damping off scare. I don't think they're over watered now, but some have downturned leaves like the first pic, wondering if it's from the fan being too close.

 

[ItsAllMedical]

Normal ? But your doggy avatar is so cute I think there doing fine nota fan of the bark in your mix it’s causing Nitrogen draw down taking N from the plant as it compost down and the paper pots are a how can I say not the best option when are you potting up .

Dog isn't my pic btw, it's Prancer, a rescue Chihuahua who hates men, children and animals and just got adopted by a single lesbian. I know he's just mad but I thought he looked like a massive stoner.