What I like about using the letterpress letters is that it is a more permanent way of labeling and you can easily fit in a long name like 'rosemary' or parsley on the marker. (click on the image to see a larger version)
All you need to make the markers is a letterpress or other labeling device, a hammer, a board to act as a cushion, and markers. I use copper ones, but you can also use zinc. I found some of the markers at Target a few years ago, but I also bought some through Gardener's Supply Company. I love the patina of the copper when it ages.
I also made some a few years ago using a nail and a template from Martha Stewart. These were also easy to make, although my fingers were a little sore after making a few of them and you would have to make really small letters in order to make longer names. I think they just get prettier over time and the great thing is I can reuse them.
Even if you can't find a letterpress set, or don't feel like taking the time to make the ones with the nail and template, it is nice to label your herbs so that you can easily identify them. Besides the ones you make will look much more attractive than those plastic ones that come with your herbs!






