I would have liked to have seen photos of the potatoes in the tower as she was harvesting them so I could actually see how high they grew, and links to her online references would have been helpful too, but otherwise Jaki’s post is very detailed, showing how the whole project went every step of the way, from building the tower to harvesting the potatoes.

I found something in Jaki’s post that might explain why potatoes didn’t develop above the first level of my potato tower. Everybody pay attention now because this might be the magic trick that makes the potato tower work. Jaki got some of her info from the Gardening with Ciscoe web site. Let’s hope it’s correct. She says:

[You] definitely cover all but the very top leaves to avoid letting sun get to the stalks and lower leaves. Ciscoe says at 4 inches cover all but the top inch. The concern is apparently if the stem and leaves get too much sun they don’t produce potatoes. That would be horrible to do all that work and get nothing.

Yeah, tell me about it.

If her information is correct, then it’s no wonder I didn’t get potatoes above the first level. I let my potato plants grow into a jungle before I piled more soil up around them — they were well over 12 inches by the time I first added more soil. Check it out:

Look at those stalks. They got plenty of sunlight while they were growing. If exposure to sunlight makes the stalks of the potato plants too stiff to sprout roots under new soil, then I spent 4 months last summer nurturing potato plants with the world’s longest stalks. Neither John Saul or Greg Lutovsky say anything about this in the original article on potato towers in the Seattle Times. Let’s get ‘em!

The relevant info comes from Ciscoe Morris who provides instructions on growing potatoes in a garbage bucket, which is smaller than a potato tower, but the process is similar. During planting, he recommends using the slow-release fertilizer Osmocote 14-14-14 that will stay active for the first couple months of growth. He suggests covering the plants with new soil as soon as they grow 4 inches. He says, “Every time the vines grow another 4 inches, keep covering all but the top inch.” So in a potato tower, you would have to carefully add the new soil by hand, building up the tower until it reaches the desired height (we capped ours off at about 40 inches because the plants weren’t growing much after that). Then just wait for harvesting time and see what happens.

Jaki at [the now defunct] Country Dreams, who managed to get 25 pounds of spuds from her tower remember, thinks she may have gotten more if she hadn’t let the plants grow out of control in the higher levels of her tower:

In hindsight I think I got lazy in hilling my potato plants as they were growing. Sometimes I would let them get to be 8 or so inches tall and jungle-like before dumping more dirt in and covering the stems. I now know that causes the plant to become a stem rather than a root, stopping growth. As it is, I didn’t get much production in the top part of the bin. I think that’s the reason. Remember, constant vigilance!

Rob at One Straw voiced concerns over this hilling process, though. Constantly burying everything but the top inch of the plant may stunt the growth so that the potato plant doesn’t develop a healthy canopy large enough to produce the sugars needed for big potatoes. But who knows, maybe the plants do well by the time they have a chance to rest at the top of the tower.

I’m almost tempted to try it again in 2010.

Related posts: How to Build a Potato Tower, Potato Tower Failure (Part 1), Potato Tower Failure (Part 2).

Potato Tower Results — An End to the Hype? by Rob over at One Straw provides a more realistic account of what it’s like to grow potatoes in a potato tower. He had about as much success as we did. The problem for us was that the potatoes simply did not grow above the level they were planted. They grew well within the first 10 inches of soil, but no potatoes grew in the other 40 inches of soil above that. We were supposed to get about 100 pounds of potatoes, but I’d say we got more like 7 pounds, probably less. We put a lot of time, money and effort into those 7 pounds of potatoes.

So what went wrong? Why didn’t it work for us? Let’s take a look at what we did first:

Our potato tower was 3×3 feet square (we used this diagram as a rough blueprint). The bottom was lined with a cardboard barrier because we have lead in our soil. The first level of about 10 inches was filled with 100% composted soil. We planted 8 or 9 small seed potatoes (a red variety, maybe Yorkland Reds? — something like that) on May 17th. We saw the first sprouts on June 7th. By June 27th, the plants were looking great. We added a second level on July 4th, covering up the lower portions of the plants with a mixture of composted soil and peat from Traverse Gardens. (We bought several bags of this soil throughout the summer as the plants and the tower grew.) The plants looked half-dead every time we built up the soil around them, but would bounce back to life almost overnight. We saw our first blossoms on July 18th. We trimmed the stems on the 3rd level thinking maybe it would provide more room for roots to grow. On August 27th, 3 months after planting, we harvested a few potatoes from the first level and they looked great. Then we left things alone until the first week of October and did our final harvest. We got some beautiful big red potatoes out of the first level. And not a single potato on the 2nd, 3rd or 4th level (each level was about 10 inches high). The potato plants had long stems. We saw blossoms only once — in July for about a week. A couple times we watered the potatoes with water that may have had some tomato plant food in them, but that was minimal and only once or twice. The plants were watered regularly and were healthy all summer long. They grew through at least 40 inches of soil to the top of the tower. That’s all I can think of it. What did we do wrong?

These are my best guesses:

— We had the wrong variety of potatoes, a red variety (Yorklands — I still can’t remember the name). Rob over at One Straw says:

Supposedly late varieties do better in towers — so look for Late, High Yeilding varities like Burbank Russet, Bintje, Romanze, Desiree, etc.

Rob uses words like “cultivar” when talking about potatoes. I don’t even know what that is, but he seems to know a lot more than I do, so I’ll take his word on it. Greg Lutovsky in the Seattle Times article recommends Yellow Finn, Yukon Gold, Caribe, Red Pontiac and Red Lasoda (at least for the Western Washington area).

— Maybe we used the wrong kind of soil. There can’t be anything wrong with our first level of 100% composted soil, but the subsequent levels were a mixture of composted soil and peat, and there may be some mild fertilizer in the mix too (I’ll have to ask Ross Traverse specifically what he puts in his all-in-one soil). Perhaps we should have added straw with more raw, loose compost. I’m not sure. I thought Ross’s soil was pretty much good for everything. Maybe not.

— We may have over-planted. 9 small potato seeds in a 3 x 3 bed. Is that too crowded? The plants certainly seemed to grow vigorously. They were healthy plants, that’s for sure. But maybe there were too many of them. Maybe there wasn’t enough room for roots to grow out from the buried stems. I don’t know (but I doubt it).

— Did we harvest too early? I doubt that too. We could have waited a few more weeks, but I can’t see that short bit of time making much difference.

— Did our initial test harvest from the first level damage the root system? I don’t know. Even if it did, it shouldn’t have made any difference to what grew above the first level.

So in the end, I don’t really know why the potato tower didn’t yield a bountiful harvest of potatoes. I think the whole thing might be a bunch of hype. I’d like to see proof from Greg Lutovsky, who may be the originator of the potato tower idea, that it actually works.

The folks over at LandShare Colorado did exactly what we did. They built a 3×3 potato tower and planted red potatoes. Everything looked great until harvest time. The potatoes on their first level were plentiful and delicious just like ours, but that was pretty much it. I have yet to find evidence that potato towers work.

Rob at One Straw says the Carola and Purple Viking varieties may do well with the potato tower method of growing — that is, roots and subsequently potatoes might grow out of all the buried portions of the plant as it grows up — but I’ll wait to see how well it turns out for him in 2010 before I take another crack at it. I would love to see it work, but I’m just not sold on it yet.

UPDATE: I think I know why most people aren’t having the greatest success with their potato towers. See How a Potato Tower Might Work.

We planted our potatoes around May 17th. We did our first test harvest 3 months later on August 17th. It looked like this:

Not too shabby. So we left it alone and let the potatoes grow until the first week of October when we just couldn’t wait any longer. This was the moment of truth for the potato tower.

We got a nice large bucket of potatoes from the first level of the potato tower. We had high hopes for the second level. And…

Not a single potato above the first level. I didn’t take any photos, because what’s there to see besides a big pile of dirt?

Rob over at One Straw (who knows a lot more about growing veggies than we do right now) had a similar experience with his potato towers. He had high hopes just like us, and like us, instead of 100 pounds of potatoes per tower, he got about 3 pounds. (Yup, it was disappointing for us too.) He had some problems with heavy rain and grew a different variety than us, but at least he got some growth above the second level (we got zilch). Rob said:

My strong suspicion… is that all the aggressive hilling perpetually knocks back the leaf growth and the plants never develop a lush canopy of sugar producing leaves to build the starch needed for a good harvest.

We didn’t have that problem. We kept hilling as the plants grew — that is, we kept burying the lower parts of the plants in soil as they grew up and up — and even though they looked pretty darn bedraggled afterwards, they’d bounced back into a rain forest of leaves within 24 hours. Our potato plants (a red variety I can’t remember the exact name of) had no difficulty growing through an extra few feet of soil and staying healthy the whole time.

The problem was that the roots didn’t grow out from the submerged branches. The original Seattle Times article quotes potato seed grower, Greg Lutovsky:

A lot of people think you plant a potato and that the new ones grow below it, but that’s not so… Potatoes grow between the seed piece and the above-ground plant.

That didn’t happen with our plants at all. After we tore down the tower, all we had was a bunch of potato plants with really long submerged stocks. They looked exactly like the plant on the right (photo borrowed from Rob at One Straw who said: “Buried ‘Stem’ had ZERO roots developed after 3 months beneath the soil”). With the exception of the first level, nowhere between the seed piece and the above-ground plant were there any potatoes in our potato tower.

The potatoes we got from the first level were beautiful, though, the most flavourful potatoes I’ve ever had. Baking them on the BBQ in tinfoil with a bit of butter and pepper — we loved every minute of it. So the potatoes did their job, but the potato tower — which was supposed to fill up with potatoes — did nothing. We would have got just as many potatoes in a 3×3-foot raised garden bed.

So what did we do wrong? I’ll try to answer that question in the next post.

Continued in: Potato Tower Failure (Part 2).

The concept is simple and very cool: plant the potatoes in a small raised bed. As the plants grow, keep adding soil, slowly burying the plants and forcing them to grow up even higher.

Meanwhile, everything that gets buried develops roots. Just keep adding boards around the raised bed until it’s 4 feet high. All the roots beneath the 4 feet of soil turn into potatoes.

In theory.

The potatoes are harvested by removing the lower planks of the tower first and working your way up.

The construction of the tower was easy: 4 square poles screwed together by 4 planks. The corner pegs or poles are about 5 feet tall. The original blueprint for the tower calls for 2-inch thick lumber covering a 4 x 4 area, but we passed on that and made due with 1-inch planks and a 3 x 3 area. We bought two 6-foot long planks (untreated, cheap knotty pine, $5.50 each), 1-inch thick, 10 inches high, and cut them into 3-foot lengths. I found four 5-foot long poles in my shed, 2 inches by 3 inches. We screwed the four sides together around the poles — nothing to it. Done. (Note: I would hate to do this without a powered screwdriver, or in our case, a drill jury-rigged with a screwdriver bit.) We placed the tower on the ground over some cardboard boxes. The boxes will eventually rot, but the tower has to be rebuilt every year, removing the soil each time, so we’ll just replace the cardboard every year. The total cost of all the materials if you had to buy them from scratch is about $25 or $30. But making due with what we already had on hand: $11.

NOTE (Oct. 25/09): The slideshow now shows the entire progression of our potato tower for the whole season.

Continued in: Potato Tower Failure (Part 1).