hunter,
Exactly, or so the theory goes. Here's what one web site says:
Another method is to put a tire on the ground, fill it with soil and plant the potatoes within the tire. Plant two seed potatoes, whole or halved, about 2 inches deep. Once the potatoes have developed 3 or 4 inches of foliage growth, a second tire can be put on top of the first, Fill in with more soil, always leaving at least 2 inches of leaf growth above the soil level. Continue to fill as the plants grow. Once you've filled in the center of the second tire, continue the stack to a height of three or four tires. Keep in mind you must always leave about 2 inches of foliage showing.
Last year, we grew potatoes in eight stacks of tires, using eight: different potato varieties. Each tire stack averaged 11 pounds of potatoes: Some readers have reported yields of up to 38 pounds per stack. Others have reported poor results, averaging as few as one or two potatoes per stack. Over-watering or the use of too much high nitrogen fertilizer could be the reason for poor yields.
The reason you can grow potatoes successfully in this manner is that potatoes develop on stems above the roots. Of course, it's for this reason that mounding or mulching potatoes is recommended so highly.
Some of the potatoes that we grew in tire stacks were: not harvested until January of this year. So the tire stacks also provided an ideal place to store them throughout fall and winter.
It makes me wonder - considering that pepper growers remark how their seedling are getting leggy because they grow toward light, I wonder if the same behavior could be use for root veggies such as beets, carrots, onions, etc. Take a 16" area, put a tire over it, plant a couple of seeds and wait for them to grow. Once they do, add a tire, fill it with dirt -leaving the original plant enough foliage to collect sunlight, but then plant another few seeds.
I will try it this summer, just because I'm curious and have to write a weekly article for my paper. Imagine growing a bushel of carrots, beets or (heaven forbid) onions in two feet of garden space per veggie.
I would probably be limited by the growing season, as we only have from May to, at best, late September or very early October before a killing frost hits. Then again, the tires are supposed to attract and retain heat, so maybe I could squeeze in 3-4 plantings.
Just for the fun of it - and of course scientific research - I plan on trying it this summer. I'm sure I can get the tires for free or close to it, so it should cost anything except time, a little bit of space and a few seeds. But if I can grow a four foot carrot or beet or a peck of them in what amounts to 1.5 square feet?!?!
Mike
