Leaf mottling problem

Surfer Joe

Well-Known Member
Can anyone please tell me what these leaves show?
They are from the lowest leaves of young nl5 x haze plants (2 weeks since sprouting) being grown in soil in small clay pots before potting up.
All 3 plants show the same effects to different extent, but the newer growth looks fine and the mottling seems to have developed only in the last two days or so.
Some of the mottled areas are dry and cracked when I grabbed them.
The temps, ventilation and humidity are fine and they are on 24/0 400W MH lighting during veg.
They are being fed a light dose of canna nutes, which I've used before with good results.
Thanks for any advice.
leaves.jpg
 
Top