Duncan Currie has something to boast about. He grew 66 pounds of potatoes in the smallest of spaces -- a circular bin, 23 inches across by 29 inches tall. Mr. Currie is a Scot, but what he did north of the English border -- and on the other side of the Atlantic at that -- is applicable anywhere. It can even be done on the smallest of apartment balconies, given moderate sunlight.
Imagine growing your own Idaho bakers 15 stories up in a Manhattan skyscraper. It's entirely possible given tub- type cultivation methods. The approach adds a new dimension of apartment farming.
Mr. Currie used a bin or barrel which is manufactured by Rotocrop especially for potato culture. But you could use any similar-sized bin or tub; even a stack of old auto tires.
There is, however, a plus to the specially made barrel that goes beyond a neat and tidy appearance. It is this: The barrel is made with sliding panels so that the potatoes can be harvested from the bottom while the plant is left largely undisturbed to continue developing immature tubers. In Mr. Currie's case, this probably boosted production to at least a moderate degree.
After planting his barrel to potatoes early last April, the Scottish gardener raised the panels (6 inches) for the first time in early August, carefully removing the bottom layer of spuds.
The tubers were clean, blemmish-free, and totaled 26 pounds, according to a letter her wrote to Rotocrop's Graham Kinsman here in the US. At the end of August he reached carefully into the barrel and removed another 23 1/2 pounds. Then the plants were left to continue growing until a northern frost finally ended all growth by the first week of October.
At that stage the barrel was dismantled, revealing a further 16 1/2 pounds of potatoes for a grand total of 66 pounds.
An average potato plant yields between 4 and 6 pounds of potatoes from good soil. Grown in the potato barrel, however, Mr. Currie's 4 plants averaged 16 1/ 2 pounds each.
That's super production in any language.
This is how Mr. Currie grew his potatoes: After assembling the barrel on a concrete patio, he first lined the bottom with stones and broken pieces of clay pots to improve drainage. (If regular rainfall isn't a part of your weather picture, or if you use a commercially prepared growing medium, the drainage stones will not be necessary).
Next, he added a four-inch layer of compost and garden soil mixed in equal parts along with a little general-purpose fertilizer. On this soil base he placed four whole seed potatoes. These were covered with four inches of soil-compost mix and watered. This was in early April
As the potatoes grew, Mr. Currie would allow the stems to appear 4 inches above the soil before carefully adding more soil and compost of within 2 inches of the top of the potato stems. He kept doing this until the soil was within 2 inches of the top of the barrel.
When the vines grew above the barrel he supported them with four stakes pushed into the soil at planting time.
The potatoes were watered regularly to keep the soil evenly moist, but not water- logged. He found, after the plants had grown above the barrel that they shielded the soil so that even during rainy weather it was necessary to water the potatoes regularly. He did this three times a week by pouring in a gallon of water each time. In addition, he applied a little general fertilizer every three weeks to boost growth.
The idea behind growing potatoes in tubs, tires, boxes, or barrels is to promote long underground stems. The roots on which the tubers form grow from these stems. So, in theory, the longer the stems the more tubers the plant will produce.
In practice, you can't force them to grown too tall. But, from Mr. Currie's experience, it would seem that potato plants can tolerate underground stems around 24 inches long because his final harvest was taken from near the surface of the soil.
One other advantage of the barrel is that it promotes more rapid growth in the early spring. This is because the barrels are exposed to the warming rays of the sun in a way that level ground never can be. In addition, it is a simple matter to throw a sheet or other cloth over the tub to protect newly growing potatoes whenever a spring frost threatens.
Beware of voles or moles if you place your potato barrels directly over garden soil. (Mr. Currie faced no such problems because his barrels were on a slab of concrete). A circle of hardware cloth or finemesh chicken wire will keep the intruders out.
A few years ago, I had potatoes growing in old auto tires stacked two deep. The spuds appeared to be doing well until one day I suddenly noticed they were wilting badly in the hot midday sun.
Assuming that they lacked water, I gave them some moisture and was gratified to see them revive by the time the sun set. But the wilting got worse on subsequent days. Closer examination revealed that a family of voles had moved in.
Only a handful of small tubers was harvested from those tires.
Any tuber of medium size or larger had been devoured, leaving only an outer shell to indicate their size.