Yellowing first true set of leaves on seedling

Howdy! Looking for some more helpful advice on this first grow of mine. Been going pretty well so far until 2 days ago the first set of true leaves began to lose their nice green color and turn pale. I didn't panic but now they're half yellow and have a bit of brown spots. If the plant was a bit older I might assume it was low on nitrogen since it's occurring with the lowest set of leaves, but it's only 16 days old and in FFOF so there should be plenty of nitro still ya? Could the high nitrogen in FFOF be the cause? The healthier new growth looks nice and green to me. Stem is green. I have it under a T5 now 18/6. 70-82F depending on time of day. I last watered yesterday with 6.6 PH and got 6.1 runoff with the little I could test. Is that too low? I've been watering about every 3-4 days when the 18oz solo cup is about as light as another solo cup I keep around of dry soil (to compare weights). Seems too early for nutes but I do have fox farms trio when it's ready. No roots showing from bottom yet but was planning to transplant in about a week. Should I just stay the course or make an adjustment based on these yellow leaves? Thoughts?

I would just go ahead a transplant into larger pots of FFOF. Then give them a couple of weeks to get use to their new containers before making any adjustments.

Alexander Supertramp said:

I would just go ahead a transplant into larger pots of FFOF. Then give them a couple of weeks to get use to their new containers before making any adjustments.

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Yea I was thinking it may be getting close to transplant time. I tried to take a peek at the roots yesterday but the soil was so dry on top I dumped a little bit out, and just decided to water before I do something stupid

Dopaz said:

Yea I was thinking it may be getting close to transplant time. I tried to take a peek at the roots yesterday but the soil was so dry on top I dumped a little bit out, and just decided to water before I do something stupid

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Yeah...lol...don't do that

I agree with the above...transplant...you can get a look at those roots then
(do it wet)

OK I got it into a 3 gallon, the smallest I had. I mixed 4/1 parts soil/perlite. The roots had not made it to the edges of the cup yet but the soil stayed together well enough. Hope it likes its new home!

your going to have to give it time to adjust to the fox farm good stuff but depending on strain it can be hot ,don't use nutes until you get first set of five finger leaves ,then hit it with 1/4 strength .

Same problem here. FFOF is super hot for seedlings. I rinsed mine a few times. Hopefully that's the issue, eh? A good way to know it's nooch burn is if it starts at the tips and spreads in.

u using R/O? looks like a lil def.looking goo tho

Thanks for the replies, here's some newer pics. It's a Nirvana Northern Light fem by the way. The yellowing first set completely yellowed up and 1 fell off, I pulled the other. The next set of leaves going up began to yellow and brown on the tips and I was worried they would suffer the same way but luckily the yellowing stopped advancing after a day or two. I'm using tap water filtered through a carbon filter. I pH it at 6.5 with pH down. The growth started back up about 3 days ago, it stalled a bit after transplanting last week. Also forgot to mention before, I have 1 Tbsp / gallon of dolomite mixed into the soil. I got runoff of 7.0 when I watered...should I pH the water lower next time I water, like closer to 6?

Dopaz said:

Thanks for the replies, here's some newer pics. It's a Nirvana Northern Light fem by the way. The yellowing first set completely yellowed up and 1 fell off, I pulled the other. The next set of leaves going up began to yellow and brown on the tips and I was worried they would suffer the same way but luckily the yellowing stopped advancing after a day or two. I'm using tap water filtered through a carbon filter. I pH it at 6.5 with pH down. The growth started back up about 3 days ago, it stalled a bit after transplanting last week. Also forgot to mention before, I have 1 Tbsp / gallon of dolomite mixed into the soil. I got runoff of 7.0 when I watered...should I pH the water lower next time I water, like closer to 6?

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Looks fine...I wouldn't sweat that run off pH...it's probably not an accurate reading anyway...

What you see in your plant is the result of its conditions 3-5 days previous. Given it has started to bounce back I would bet it was lacking some nutrients. Now that its transplanted and adjusted it looks good. Ned Tim you start to see some yellowing throw it a low dose of grow