HELP! Leaf problems and slow growing

[Sugaree]

Second grow but first in a few years.. My primary problem are these leaves! I can't quite match them up to diagnose the problem properly. They seem quite washed out with dark veins. My secondary problem is that this baby sprouted 21 days ago and appears to be growing super slow.

So here's what I'm doing..
Lights: 300w LED Mars Hydro about 16” up. (Oops, seemed like it was closer to 20-24")

Schedule is currently 24 hours just to get going and was about to switch to 18/6. I turned them off for the night thinking I overdid the lighting

Medium is 75% coco and 25% peat/vermiculite.

Watering: well, the first week or so I think I overdid it a little since I'm not used to a medium holding moisture so well. Been working so I actually forgot to check on her for almost a week and is still slightly damp.

Nutrients: I cheated here because last time I did full hydro and it was a lot of work. I am trying the kit from Nirvana seeds.. So the root extender granules and a soil tab, which is a slow release table a few inches below the roots.

I hoping I was just a bit overzealous in the lighting. Any thoughts?? Thanks!!

[Farmall2]

There seems to be a deficiency developing but may be falsely indicated by nutrient lockout.... have you tested the ph of your watering solutions going in and the run-off coming out?

[Sugaree]

The water ph was just lab tested about two weeks ago at 7, my home tester gave me about 6.9. The runoff is about 8.5 now. I only use straight water since the slow release nutrient tablet is in the soil.

[D.A.A.S.69]

I think that's your problem right there, if your growing in coco, ph needs to be in between 5.5-6.5.
If you ain't got a ph meter you need to get one, the little yellow ones on Amazon for bout 20bucks work fine.

[Sugaree]

Okay, I have a bottle of ph Down from when I did hydro last so I'll flush out with 4.0 water and see how that goes. Up until about a half hour ago I had a ph tester but I broke it after I got those readings. Story of my life. So yes, I'll be getting a new one now! Thanks!

[Canuck147]

Grow medium is a bit short on perlite - roots are having a hard time spreading - so - slow growth.

[Sugaree]

On hand I have a lot of LECA. I was just thinking of repotting with a bunch of that layered in. Do you think that is sufficient?

[SoOrbudgal]

Yes I concur with the 2 comments above. If it's not an auto transplant it mix 30% of soil volume with perlite make sure there are no nutes in that soil mix like a slow release. New starts don't like nutes they just want loose fluffy soil medium. 18/6 on off . Good luck

[D.A.A.S.69]

What brand of coco are you using? Did you rinse it a couple of times first, if it wasn't already ?
Are you using Cal-Mag?
Some folk say you can't overwater in coco, but I believe you can if you ain't got enough perlite in it, like Canuck147 said .
Looks like it's short on nutrients to me, how long has that tab been in there?
In coco you can start feeding after the first set of true leaves show, unless your using something like Coco-Loco, that's got nutrients in it.
Have you been phing your water?

[Sugaree]

Plantonix coco coir. It's supposed to be buffered so no, I didn't rinse. Being too trusting is sometimes my downfall. And yes, I agree, it definitely can be overwatered! Never used it before and it seemed so nice and fluffy but it holds water way too long. I've been doing semi-hydro for years (for my orchids) using LECA and the aeration makes the roots grow insanely well so it makes sense that this medium is too heavy to be used alone.
The nutrient tab has been in there for 21 days since I germinated the seed and potted it. I followed the instructions and placed it a few inches below the sprout so the roots get down to it. When I just scooped the seedling up though, it was gone. Didn't think a slow release tablet would be gone at this point. So I think I'm gonna need to find something new to put in the water moving forward.
I am not yet familiar with Cal-Mag so I suppose I'll be reading on that next.
And the water ph is 7.

[SoOrbudgal]

I don't know what LECA is imma looking it up now

[Sugaree]

It's lightweight expanded clay aggregate. I use it to grow semi-hydro for my orchids and for regular hydro with my first marijuana grow. That stuff is life-changing! The only reason I didn't do hydro this time was out of pure laziness, but I see where that has gotten me!

[Farmall2]

Sugaree. I would think once you’ve corrected the problem, you’ll have a successful grow as so many here have used nearly every medium to grow in. Some of the successes are remarkable,. That tablet in there bothers me but I don’t know it’s make up.

[SoOrbudgal]

Sugaree Oh OK got it thanks