Something wrong with my seedling!

[Wienerwoods]

My Delahaze seedling is soon 2 weeks old. She's been on 12/12 from sprout. Yesterday one of her newer three-fingered leaves started curling up from the sides but I didn't think much of it. Today I woke up and saw this on the same leaf:

It looks a bit less moist and not rotten in person. The brown areas appear transparent, almost like bite marks under LED lights.

She's never been watered. The soil has been reasonably moist for the whole 2 weeks. I was planning on watering her today, though. The soil shouldn't be too hot as I've heard many people using it over the years. pH should also be correct (soil was supposedly 6.2, it's been pre-watered once three weeks ago using molasses mixed with tap water whose pH is 7)

I saw a small white insect in the soil before planting and sprayed the surface of the soil as well as the outside and surroundings of the container with pyrethrin. I also have an earthworm living in the soil.

Temperatures have been around 75 Fahrenheit all the time, never dropping below 70. As for humidity I have no idea. The air in my cabinet is being changed constantly, at least once a minute according to my calculations.

She's been very close to a 10W LED bulb all the time and enjoyed it. The signs of sickness appeared during last night's dark period.


Any ideas?

 

[Muddy]

Could be an insect or a deficiency/pH issue, kind of early to say for sure. Do you know the actual pH of your soil? Just because it's supposed to be 6.2 doesn't mean it actually is. Also, what is in that mix? From the little of it I can see in your picture I'm not seeing any perlite.

 

[namvet25]

What kind of mix are you using?Why are you doing 12/12?What is the pot covered with foil?

 

[Wienerwoods]

It's a local gardening soil that doesn't contain any perlite. Slush test showed about 6.3, run-off was 6.5. It contains different kinds of peat, fine sand, some clay, some dolomite and some basic nutrients as well as compost. I know it doesn't sound ideal but it's a tried and tested soil where I live, even for cannabis.

The stem got stretched during the first week, the seedling tipped over. I buried the stem and added more lights. The foil tape was there to make sure the seedling won't dig itself up. It didn't touch the seedling and it wasn't in the way of anything.

Doing 12/12 from seed is part of the experimental nature of the grow and I couldn't get any perlite so I just left it out. While I acknowledge that perlite is hugely important in the mix, I do not see it as absolutely necessary.

I'm almost certain that it's because I had the lights way too close. The damage appeared in under 48 hours and in the exact spots where the beam was the brightest. The LEDs are 10W grow lights (about €2 each from China) and I had them only a few inches away.

I'd like to know if that's a valid theory.

 

[Muddy]

Unless the leaf was actually touching the light I wouldn't expect to see that. It does look like something chewed on it or perhaps it was damaged when it fell over so I'd suggest waiting a bit to see if it shows up on other leaves.

Clay and sand are two things you certainly don't want in a MJ soil mixture. Both tend to compact the soil and cut off needed oxygen to the roots. Adding perlite would have helped and is pretty much a necessity in any good soil mix. While you may get satisfactory results, I certainly hope you do, I think you would be better served to look for a more MJ friendly soil mix your next grow.

 

[Eyes on Fire]

did you spray the surface of the pot while in seedling stage or prior to planting into the soil directly.try fluffing your soil to hasten some evaporation and its possible maybe that the spray made it slightly harder to breath the soil and its too moist in the lower end of the pot throwing things off?I had a similar issue once.no bugs but just an idea.fluff,small fan and next watering use a surfactant.