More On Potatoes

It's still a mystery why my potato box experiment was a failure. Fellow blogger H2 came over with her new flipcam on the day I took the box apart--in search of my advertised 100 lbs of tubers--to shoot this short video.



As the clip ends, we're heading to the roof to see how my SIPs planted with sunchokes, aka Jerusalem artichokes, did. A preview of what we found can be seen in this picture.



I'll post that clip next.

[Updated 11,04.09. I'm not the only one who can't get them to grow in boxes. Rob, at One Straw, had the same poor results.]

Man Humbled By Potato

Without giving it much thought, this spring I decided to try growing potatoes in a box after reading a story in the Seattle Times.

It didn't work. From an initial planting of three pounds of seed potatoes I harvested one and a half pounds of potatoes. That's right, I went backwards. A far cry from the 100 lbs(!) or more mentioned in the article.


After swallowing my pride and setting aside the feeling that I was a fool for wanting to Believe, I came up with a few thoughts on why it didn't work.

The first might be that I planted the wrong variety, i.e. not late season, of potato. Inca Gold are a mid season potato; I've read that you should avoid early season varieties because they only set up one bunch of potatoes. While excavating the potato box, that seems to be what happened in my case. All the vines grew 12-16 inches, set up one cluster of potatoes, then no more. That's still only a partial explanation. I should have a lot more than 1.5 lbs from one "set" of potatoes.

One clue that things weren't going well was a dearth of flowers on the tops of the finished vines. Flowers are a sign that the tubers are setting up, I only remember seeing a couple in mid-August.

It was very cold this summer in Chicago this year, though I don't think that's the answer. I found a couple of slugs inside the potato box, but the potatoes, and vines, didn't look gnawed on. The plants looked healthy, suggesting they had enough water and fertilizer. I've grown tomatoes successfully on the same spot--in the ground, not in a vertical tower--in the past, so I think it gets enough sun. With so many variables, it's hard to know what went wrong.

Honestly, I'm at a loss. I was hoping to at least be able to figure out what happened. Maybe some of our readers will have a clue.

I plan on reusing the soil, a mixture of coir, peat, and vermiculite, in my several of my rooftop SIPs next year.

I'm not sure if I'll try growing potatoes in a box again. I'd like to try something more conventional, like growing them in containers.

Potato Box Update

Back in May, I planted 3 pounds of Inca Gold seed potatoes in a 3' x 3' x 3' cedar box on a strip of land next to my garage.


As the seed potatoes sprouted and sent up vines, I added a new board to each side and covered almost all the new growth with fertilized potting mix. In a couple months the vines were all the way to the top. The idea, cribbed from an article in the Seattle Times, was that tubers would sprout along the entire length of each (covered) vine to fill up the entire box with up to 100 pounds (!) of new potatoes.

Ordinarily potatoes are planted in the ground and produce tubers at the ends of the roots. Here's what a potato plant looks like in normal growing conditions:

By continually covering the growing vine with soil, I'm turning the green vine into a very long tap root. Off of the entire length of that root, the plant will produce tubers.

If you're looking for instructions on growing potatoes in smaller containers, Love Apple Farm has a good tutorial.

This pic, taken August 14th, shows plenty of healthy vines climbing out of the box. A good sign.

They started setting up flowers around the 1st of August. Since these first blooms I haven't seen many more. That doesn't seem right.

Two weeks later, it's time to check for new potatoes, at least according to this link.

"You may begin to harvest your potatoes 2 to 3-weeks after the plants have finished flowering. At this time you will only find small "baby" potatoes if you were to dig up a plant. Potatoes can be harvested any time after this, by gently loosening the soil, reaching under the plant, and removing the largest tubers, leaving the smaller ones to continue growing. If you want late potatoes for storage, wait 2-3 weeks after the foliage dies back."

They said baby potatoes, nothing about peanuts.

After I took off the bottom board on one side, I stuck my hand in about 5" looking for potatoes. All I found was a peanut, probably left by a squirrel when there wasn't much dirt in the box.

I'm going to let them grow a little more and then pull the whole thing apart in mid September in search of my 100 pounds of potatoes.

Stay tuned.

[Update 10.6.09, Potato Harvest results]

Potato Box - An Experiment

I have a small strip of land that gets 6 hours of sun a day. It's the perfect spot to try growing potatoes. Vertically. In a box.



I got the idea from this article in the Seattle Times. The hook is that you can grow a lot of potatoes in a tiny space; just what I need.

Greg Lutovsky, who has been growing potatoes as a business since 1993, says you can grow 100 pounds of potatoes in 4 square feet. All it takes is some lumber, seed potatoes and careful attention to watering.

The story was enough to get me started, but it's a little short on practical advice. For that I turned to Sinfonian, who meticulously documented his potato-in-a-box efforts last year.

The idea is to pile up soil around the growing potato vine, adding more soil--and boards to the side of the box--as the vines get taller. Potatoes will grow between the seed piece and the above ground plant.

When the plants start flowering, after about 100 days, you can remove a board or two from the bottom and fish out a couple of potatoes. Or you can wait until frost kills the plant in the fall and harvest them all at once. There are plenty of sites that explain how to store potatoes. With a bit of luck, I'll be doing that this fall.

If you want to grow vertically, there are several alternatives to choose from: grow bags, wire cages, stacked tires, large containers. All had drawbacks, so I chose to make my 3'x3' bin out of cedar fencing boards and southern yellow pine. I gave all the pieces a coat of linseed oil, hoping that this will protect the wood from rotting.

I bought, and then chitted, 3 pounds of Inca Gold seed potatoes from Ronniger Potato Farm. Inca Gold are late season potatoes, an important detail for this type of growing. According to Sinfonian, early season varieties only set fruit once, making them bad candidates for potato towers. You'll end up with a few at the bottom of the box and that's it.

I just planted my seed potatoes today. As they grow, I'll add more cedar boards to the sides of my box and cover them with dirt.


I'm following the same method of piling up soil around a growing vine--but with sunchokes-- in SIPs on my roof. I think you could do the same with potatoes.


[8.26.09, update on potato box]