Leaves are beginning to yellow

I don't know if this is a problem or not, but the baby leaves (I dont know what they are called but it is the very first set of leaves that pops up and they are round and obviously different from pot leaves.) are beginning to turn yellow.

I am growing two plants and each is about 4-5 inches tall. They are planted in soil that has fertilizer mixed in so I have not started fertilizing yet. I don't THINK I am over-watering because all the other leaves look fine, there is no yellowing or leaf-curl. They are still in the small plastic cups I sprouted them in.

This is only my second shot at growing so far, the first plant I grew turned out to be a male, so that was a bust. On my first plant the baby leaves did the same thing (yellowing) but not as quickly as these two.

Do these leaves naturally die off? Or is it a sign of a deficiency somewhere in the system? My grow room stays at a constant 67 degrees F. and I am using a 250w hps.

 

I would transplant them into a bigger area

 

Thats completely normal,those first leaves are called cotyledons are are what supply the plant its nutrients and photosynthesis till the first set of true leaves emerge.All is well.Peace

 

Thanks for the peace of mind, meangreen.

I love this forum.

 

what about yellowing of the bigger leaves, but only some of them?

 

If its on the older lower leafs its more then likely a N deficiency.The plant will take N from these leaves first if there is a shortage ther of in its diet.Hard to say without seeing but most commonly run into a N or Mg deficiency.This deficiency is quite normal as the flowering cycle moves along its path.