yellowing spots on bottom fan leaves

can someone help me with this please? im not sure whats happening to the fan leaves, but I dont want it to continue if I can help it!! i just did my first full soil flush today in hopes that its only a buildup of some sort. if its a N defficiency or anything else please let me know!! the rest of the leaves arent showing any spots or yellowing, just the bottom 2 fan leaves.


ak47 lowryder auto - about 30 days old under 4x26w day/2x26w soft cfls.. 20hr/4hr cycle. temps 72-78f - humidity 39-56%

soilmix: 1/4 MG Seedling soil, 1/4 MG Reg soil, 1/4 vermiculite, 1/4+ perlite

watering only when top 2 inches of soil are really dry - no nutes added yet other than what was with the MG soil


peace

Methinks its Magnesium problems.

shit could be a million things
-first off she looks very dark green with bright yellow viens-sign of too much N.
-that spotting can be Ph related
-could be an Magneisum issue
me thinks overwatered with improper ph water/runoff-possibly becoming root bound

all just a guess from those limited pics

thx for helping! i think the runoff is decent with the amount of perlite that i put in the soil mix. the pH has been around 5.8-6.2 but i will check it again soon after this first flush has dried up just to be sure. i will keep an eye on it and post up more pics if it doesnt look better by tomorrow.

I would try getting my runoff to 6.5. and judging by those fans looking all dark green and almost leathery, I wouldnt nute for a while. but what u can do is add some fine dolomie lime to your soil-will help keep the ph up and provide essential maro nutes of mg and ca, which she will need.

otherwise they look good and bushy-

yea i guess i need to switch to something thats not MG based soil next grow to avoid any possible nute issues. i was hoping that with it being a auto lowryder it would use the nutes up faster in the early stages of veg and then be ready for water fed nutes during the month of flowering

i sliced off all of the yellowing/spotted leaves with a razor blade to keep from wasting the plants energy. i'll keep a watch on it over the next day or two and keep you posted.

looks like u r gonna have to repot in the future- 2weeks?