Why don't you grow it from seed? I've managed to do it successfully with
seed from a supermarket designed for culinary use.

I've had great success with seed from indian supermarkets.
Coriander, dill, mustard and fenugreek have all been successes and at prices
well below any seed merchants. The last two have mainly been used as green
mulches on newly dug soil. However, I've given up with
coriander because of its tendency to bolt. I found it less trouble
to buy bunches of the herb ready grown and cut at the very same
supermarkets and freeze those.