One of the greatest benefits of a railing planter box is its ease of maintenance. Because a railing planter box sits high this makes a railing planter box ideal for the elderly who wish to continue gardening but are not long physically able to handle ground gardens. Of course, one need not have physical limitations to appreciate the ease with which a railing planter box may be maintained.
Railing planter boxes are also especially nice because they are very visible. With a railing planter box you can enjoy beautiful live flowers all day, whenever you pass your balcony, not just when you go outside. This high visibility does more than just showcase your plants, it also provides a handy reminder for those who like gardening but suffer from forgetfulness-induced brown thumbs. It's much easier to remember to water your garden and to see if your plants need special attention, when they are prominently displayed in your balcony.
Of course, the real incentive behind a railing planter box is the ability to garden where you have not been able to before. For many city dwellers and the vast majority of apartment owners, yard gardens are not realistic for the simple reason that they have no yards. Conversely, the immensely satisfying hobby of gardening is available to anyone who has railing (and almost everyone does have at least one) by means of a railing planter box.