Whatever preconceived notions you may have regarding the collection of yields, the fact is that knowing how to harvest coriander can be learned by anyone who is willing to spend some time studying the matter.
Step 1 on how to harvest coriander: timing is crucial
The amount of flavor that you can derive from the herb will depend on the size of the plants. For the best results, you should start harvesting only when the herbs have reached a height of 15 cm or so (that is about 6 inches).
A note here: do not be surprised if you find cilantro and coriander used interchangeably on the Internet, because their properties are virtually identical, and the way they are planted and harvested is identical.
Step 2 on how to harvest coriander: storing options
As with most herbs, coriander is best consumed after being plucked from the plant, as the flavors are still fresh. However, if you want to keep some of them in reserve, or you are going to use the herbs for other recipes in the coming days, you may store them in plastic bags. For added protection, cover the herb with wet towels. If you store these in the fridge, you will be able to use them for another couple of weeks.
Step 3 on how to harvest coriander: dry or frozen
There are two other ways that you can make your coriander last. One is to freeze them. What you do here is to take the leaves and keep them among several ice cubes or place in the freezer.
If you want to dry the herb, slice the stem off the plant and put it in a closet or drawer so it can dry (do not forget to put them in a bag). When it has dried, remove from the bag, and put the seeds in an airtight bottle.
Step 4 on how to harvest coriander: do not transplant
If you want to have your herbs in good condition, do not move the plant around, as it does not respond well to transplanting. Also, you may want to check for insects, although pests are usually a non issue when it comes to this herb. What you need to watch out for instead are fungi, which can appear during rainy season. The key here is a well drained soil.
There may be some differences when raising variants, but in general, that is all you need to know on how to harvest coriander.