Maybe a little slow, but be patient. It's not how they look in the first few weeks, it's how they look at harvest. They always seem a little slow at first, then boom. Off they go. How far away is your light? What kind of light is it? Do you have plenty of aeration in the reservoir? Are they from seeds or clones? If clones, did they have a big or small root mass? Clones usually start a little faster and bigger than from seed.