I grew coriander from seeds and the plant has done marvellously well until the last week or two where it appears to have stagnated a little. I noticed that some leaves have began to brown entirely, while others have brown tips.
This is a potted plant in heavy soil. I was very generous with fertiliser, and I do water on most days save for overcast and rainy days. I notice that the water takes a while to be absorbed into the soil. The soil is constantly wet too. I'm afraid I might have planted it in too heavy soil.
There is drainage below the plant. I used a bed of stones in a plastic pot with two holes. But I think the sand might be too heavy.
This plant gets at least five hours of sun, maybe more, on on sunny days, and the weather is sunny and mild year round (São Paulo, Brazil).