Indoor herb pots

[WriteforFun1]

Novice alert so may be a very stupid question

I have grown some herbs from seed in a kit, indoors. The basil and chives are flourishing (and tasty), but the coriander looks mad. There are some very short shoots and some very long full leaves as well as some totally bald spots. I spread the seeds the same way in all the pots, so just wondered why this happened.

Also, probably a really silly question but for all 3 plants, I presume I just pick the useful part of it? Should I snip them off at the head or the root to encourage further growth? I've been snipping at the head so far.

The coriander tastes good, it is just the growth is so uneven.

Thanks.