3.5 weeks old yellow leaves?

Hey all, can anyone tell me why she is exhibiting yellow leaves this early? Also, what is the reason some of the leaves are curling?

i would suggest its overwatering, there are also signs of interveinal chlorosis, sugesting magnesium deficiency, nutes should not be too strong for that small plant, ec about 1.00 should be fine, try foliar feed with epsom salts to sort out mg def, there are lots of posts about this check one or two out, for the strength to foliar feed.

the pH is fluctuating to much causing a light to no uptake of micro-nutrients.

It's hard to tell with that photo, but it doesnt look great does it? What's your RH at? Those leaves look very thin, and maybe brittle. I hate to pour too much information into this thread, becuase the two people before me already offered a lot of goodf advice, but when leaves look super thin and papery (see how the serrated edges are all going different ways and shit?) Usually the relative humidity is too low. Having thick, lush leaves in veg stage really gives your plants a buffer. 1/2 a millimeter more in leaf thickness would make your plants incredibly more resilient to stress. I recommend 80% RH at 80F for vegging, and prolly 65-70% RH at 74 degrees. That's just an observation. What lights are you using? Most noob problems are people using normal nutes with shitty lights. The plant isn't metabolzing the ferts correctly, because it isnt photosynthesizing enough. So check your lights, check your PH, and get that humidity taken care of. It might be overwatering, but you're in hydroton, so that wouldnt be the first thing I'd look at.

Just a small little tip, but the plant looks fragile overall. I might be way off, I hope I haven't convoluted the problem.

she looks like she needs to dry out

Shes in a hempy bucket right now. I water every other day and I'm giving her 1/4 strength grow big twice a week. With regard to RH, it's at 30% right now so I will get a humidifier in the tent. I have 4 26w 6400k cfls on her right now. The temp is at 73F. Thanks for all the help. I some calmag I bought that should be here in a couple days.

Yeah thats about as i suspected. I'll tell you a good safe additive is Carbo Blast or a similar dextrose/mag product. The carbs are good at all stages, as is the magnesium. One thing I like about these additives is they are very safe. Extra mag, or carbs arent going to hurt anything, unlike some micro nutrients that can easily be over done. Your plant though will be in general a much healthier girl during vegging at high humidity.

Edit- also that PH? In Hydroton your plants can show some serious defeciencies when the PH flutters around, or over 7.0-7.1 Not all nutes can be used by the plant over that PH number. So what happens is that your food is fine, the nutrients are in the mix correctly, but because the PH of the water is too high ( most common) or too low ( kind of rare ) the plant has no access to them. Do yourself a favor now, and get a PH tester, if you dont have one. If you do have one then check everyday before you feed.

Good luck bro!