That does look like a trace element deficiency having checked the following link
The Complete guide to Sick Plants,pH, and Pest troubles! - International Cannagraphic Magazine Forums (good symptom pics). In which case a complete trace element solution would hit the spot though I wouldnt overlook the obvious like not enough water or too many ferts. The browning of leaves could also be a too low or high ph so testing the surrounding soil would also be a good idea this would also lock out trace elements, parasite infesestations should not be ruled out imho.
The ground/surrounding your plant does look very dry/sandy (sand drains quickly) and the soil surrounding your plant stem looks lighter than your first photo indicating some dryness. I would give lots of regular waterings for 3-5 days to ensure water or too many ferts is not the problem. Should moisture retention be a real issue try digging in vermiculite or coir pete bricks both of which will retain moisture if you have a prolonged dry spell. I also noticed your friends nice plants also have much larger areas of turned over/quality soil which would hold more moisture and allow the roots to spread easier. The dry looking soil surrounding your plants may well soak up any waterings you give.
Should the problem persist try the trace element additive, seaweed or kelp based liquid additives would be one organic source, ask your local hydro or garden store. This type of liquid should fix this problem quickly. Adding this regularly during veg will be beneficial regardless but could make an overfertilised plant worse.
Parasite infestations can be real tricky as different problems require different treatments and is something I dont know enough about to recommend a proper solution. I do know that just because you cant see a problem it doesnt mean that a nasty little bug isnt eating the roots of your plant.
I'm no expert but the above are logical reasonable steps to identify/remedy a possible problem and are just my thoughts, a ph kit can be bought from most garden/hydro stores for as little as a few euros and should be in the above list somewhere.
I really do wanna see how this Alaskan ice turns out as my five seedlings are now coming along nicely after 2 weeks and should be ready for the outdoors in another couple. I just ordered a 150w metal halide lamp to bring them on a little faster as my 70w hps is really lacking the UV content for real nice veg growth, though it has done 20 seedlings in 2sq ft nicely up to now. Your grow will give me a nice idea of things to come, good luck
Keep it green.