Small Leaves is there a problem?

Hi there
My plants have small leaves they were clone's
What would make them grow like this?
Please help
Thank You

there are several reasons this could be, depending on the strain of marijuana the leaves may genetically be small, there may not be suffecient space for the roots in the pot e.t.c and the plant may be root bound, or if your plants are new clones you won't see much leaf growth as they concentrate on producing roots just now.