For as young as they sound, they may have nutrient burn. Which is normally caused by too much, or started to early. If the plant is less than 4 weeks its best to wait until its 4th or 5th week. And I only start it at 1/4 strength just to be sure the young plant can handle the nutrients.

Also, how much water are you giving them, Potted or Earthed? Indoor or Out? And what is this "shade cloth" you speak of. MJ doesn't want shade, she wants Full Sun!

And, if you can get a few pics posted it would greatly benefit in our aid to help you.

Toodles..!