Potatoes are an easy-to-grow garden staple. You don't even have to plant potatoes in soil to produce a good yield. Many gardeners have heard about growing potatoes in straw-filled cages, but there is another growing medium in plentiful supply in coastal areas -- seaweed. Using the same method as growing in straw, you can grow potatoes in seaweed. It is not only simple to do, but it also lends a distinct and somewhat salty flavour to your potatoes.
Set up your cage in a sunny location in early spring. You can make the cage from a variety of materials, including plastic mesh and chicken wire, or purchase a ready-made cage from your local gardening supply store. The shape is unimportant; it can be cylindrical, square or rectangular. The only thing that matters is that it has enough holes for the potato vines to grow through and enough substance to hold the seaweed and potato plants in place.
Place approximately 1 foot of seaweed into the bottom of your cage. Then, place the seed potatoes along the edges of the cage, eyes pointing outward, 8 to 12 inches apart. Cover the potatoes with another 1 foot of seaweed and repeat layering in this manner. On the top potato layer, however, place the potatoes with the eyes pointing upward. Placing the potatoes in this manner allows the potato vines to grow out the sides of the cage and up through the top opening.
Water the potatoes as needed, which is usually infrequently since seaweed retains moisture well and coastal climes tend to have a lot of moisture in the air. To know when to water, periodically check the moisture level in your cage with your fingers. If the seaweed feels dry, add water.
Harvest your potatoes at the proper time. This will depend on the potato variety you choose, but it is usually within three to four months. When the potatoes are ready, simply reach into your cage and pluck out the potatoes. Store your harvest in a cool, dark and well-ventilated area.