Why rewrite what has already been written about our dear Corie, aka coriander, when Penny Woodward from Organic Gardener Magazine has already done a such a bang up job.
Best grown from seed sown directly where they are to grow. Once you start moving them around and transplanting them it only increases the speed before they run to seed or shortens your harvest time..
Also regular picking or harvesting, whether youre using it or now will add to the life span of your coriander. This also applies to most other herbs as well.
So, get sowing, now's the time!