First, I would not attempt to grow cilantro indoors. Indoor growing conditions are not well suited for any kind of herb (other than tropical ones) and even with no real garden, you can grow cilantro in just a flower pot outside. It would be much happier!!

Cilantro grows rapidly and should be harvested on at least a weekly basis. Cut the plants back by half to two thirds. And do not let it develop flowers - when it bolts and sets flowers, the leaves lose much of their taste and become bitter. Even when grown outdoors, cilantro is generally succession seeded every two to three weeks as it will grow very rapidly and begin to flower and set seeds in just a couple of weeks.

I think cilantro is the most difficult herb to grow and I agree that it is better grown outside. Here in NH I have a high tunnel where it self seeds. Right now I have a neglected forest of blooming cilantro that needs to be torn out. I have smaller plants here and there, There are a few recipes that call for the seeds but those are usually baking recipes. I have no idea how growers who supply grocery stores get such nice thick leafy branches.

Coriander seed is key in much Indian cooking. I use it in lots of savoury dishes.

floral_uk, thanks for the Indian cooking info. I shouldn't have made the general statement that coriander is mostly for baking.

It's true, in the U.S., for American foods, coriander is mostly seen in baking recipes. But I use it with veggies a lot in stir fries. I also use it, along with a good measure of cumin and cayenne, to add a nice earthy flavor to the cheap supermarket brands of salsa.