Even though the herb may not be as popular or widely used as other herbs, learning how to harvest arugula is easy, and the process and measures you have to take are similar to other plants and herbs.
Step 1 on how to harvest arugula: determine how many are required
Arugula, like other herbs and plants, will grow even when the leaves are cut or some stems are removed. However it is essential that you exercise some prudence here. Only take the ones that you will actually use (and maybe a few as reserves). By letting the plant keep some leaves, it will be able to regenerate more quickly.
Step 2 on how to harvest arugula: cut the leaves with care
Unlike other herbs which you can slice and dice easily, collecting the leaves from this herb will require that you cut the leaves in a particular way. You have to start from the base, and work your way from there. As you cut the leaves, make certain that the ones at the center are left intact. This is necessary for the herb to keep growing.
That last point needs to be emphasized, because if the whole plant is deprived of the leaves, it might cause more harm to the plants. It may not just limit the growth, but the re-sprouting of leaves may take longer, or may stop altogether.
Step 3 on how to harvest arugula: consume only seeds you have grown
Whether you are collecting the plants or the seeds, examining the plant is always mandatory, regardless if you are going to make the seeds / leaves for cooking purposes or propagation. It should be made clear that while seeds you have grown can be consumed, it is not recommended that you digest the seeds that are bought from stores.
Those seeds you purchase from the store are meant for planting only. This is a fact that everyone who wants to study how to harvest arugula must be aware of. These seeds are very likely to have been sprayed with chemicals so only use them for cultivating new herbs.
Those that want to gain more than basic knowledge on how to harvest arugula do not need to delve into books. Rather, it is much better if you just go to the garden or tend to your pot regularly. This will help you develop the skills you will need as time goes by.