Yesterday I wrote about potatoes, their seeds, and how they are typically grown. I ended the post on the note that some might question the potato's place in the kitchen garden given the space that it normally takes to grow them. Often viewed as a field crop, potatoes have a unique property that allows them, with a little planning, to be successfully grown in samll areas. This property is the ability to convert leaves and shoots into roots when covered with soil.
Typically, potatoes are planted in rows and, as they grow, are 'hilled.' This means that as the plant gets larger, soil is periodically piled around it to protect the little potatoes from the sun. Unlike most plants, potatoes do not send roots down into the ground. Rather, the seed potato marks the bottom of the root system. Potatoes, you see, grow up!
In this image, the seed potato was one of the potatoes at the bottom of the bunch. The others all formed either around or above the seed.
All of this hilling takes up space in the garden or in the field and makes getting a lot of potaotes tough in a small area. The trick is to grow them in a different way. Because potatoes grow up and because, as I said before, they are able to magically turn leaves and shoots into roots when covered in soil, the best way to grow potatoes in small spaces it to grow them vertically.
Enter the potato box.
This ingeniously simple little device allows potatoes to grow vertically and allows them to convert their leaves and shoots into roots and thus form more potatoes in the same space!
Building one of these boxed is quite simple because it should be small (no larger than 3ft by 3ft) and it can be built with standard sized wood available at a local home improvement store. I would recommend using a non-treated (no nasty chemicals)but rot resistant wood like cedar, redwood, or cypress. While more expensive than treated wood, the box should last a number of years and will not leach anything harmful into the soil or the potatoes.
Here is a example of how to build one of these.
Step 5 is absolutly critical to the success of a potato box. As the potatoes grow, soil has to be added to the box. By covering the leaves and shoots of the plant, the plant is tricked into forming more potatoes. Also, you wouldn't want to eat any potatoes that have been exposed to the sun - they'll be green and they'll make you sick. If you follow these directions, plant 4 potatoes evenly spaced in in a square. If you decide to build bigger and step up to a 3ft by 3ft box (36in by 36in), again plant 4 potatoes in a square but put a 5th in the middle becasue of the extra room.
Unofficial reports state that 5 potato plants grown in a 3ft by 3ft box can yield as much as 100 pounds of potatoes!!! Given that the average American consumes about 45 pounds of potatoes each year, 1 box might be all that a family needs.
Remember, potatoes attract bugs and soil deseases that are super-hard to get rid of. Rotate the soil in the box each year with soil from a different part of the garden to be sure that all of the critters are kept away from the potatoes.
For those who don't want to take on the project of building such a box, pre-made potato bags are a great option!