Dislikes heat and too much sun. Once the plants grow beyond the flat parsley shaped leaves it bolts and will not produce any more cilantro leaves. The bolting results in thinner narrow leaves that are tougher and then they flower and go to seeds. Suggest you do a aearch for teh key word 'CILANTRO. There are MANY cilantro threads as below:

Here is a link that might be useful: Cilantro search threads

You are I are neighbours. Here in Brisbane at the moment we're going through a very unusual winter heatwave - we've missed out on spring altogether. We went straight from winter to high summer in 3 days! It bodes very ill for the real summer, thanks to El Nino, our worst enemy.

Coriander doesn't like our heat, so it will do best in our winters. THEN it will take some sun, but otherwise it should be in partial shade. Even then it will only last for a couple of weeks before bolting to seed. You'll see this about to happen when the leaves change from parsley-like and go all lacy.

You can let it go to seed, and eventually you'll get more plants coming up, but they won't do so well when the real summer hits us. You can always save some for next autumn/winter.

I'll bet you got a big plant in a little pot, too. The pot will be full of roots and have very little soil, so all the water you offer can't be taken up.

Try transplanting it to a cool spot, but do it with crossed fingers, because then it will have to contend with transplant shock. I think your coriander is doomed. You've got a winter-grown plant now suffering from heat-stroke, and we're not about to produce any more cool weather for it.

BTW, Americans call the plant cilantro, the Spanish word for the plant. They call the seeds coriander. Since we don't speak Spanish in Australia, we just simplify matters and call it coriander, the name derived from its botanical name, Coriandrum sativum.

You could try using Asian Coriander, Eryngium foetidum. It looks nothing like coriander, but it has a strong coriander taste, and it will do very much better in our climate. Only for flavouring, though. Not for garnishing. It grows like a weed here.