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Post by nathanp on Mar 28, 2016 19:07:35 GMT -5
Just a brief followup. I think I mentioned this previously, but Simon Smart, who is a student at Girton College, University of Cambridge (and also a member of the Kenosha Potato Project), has been doing his doctoral thesis and research on spacing of potato plants, and how that affects yield at different spacings. Here is what he says:
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Post by nathanp on Mar 28, 2016 19:15:08 GMT -5
Ok, these are two much larger images. Hopefully the website allows images this size. These should be the full size images of two of the Boyd Dude TPS plants. If you save the full size images, you can zoom in at the ends of the stolons and see tiny potatoes forming. Boyd Dude TPS 1Boyd Dude TPS 2These were taken on October 4th, at the tail end of my growing season, and were still growing when I pulled them. Long season, chain sets tubers on stolons.
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Post by gilbert on Mar 28, 2016 19:32:29 GMT -5
Hi Nathan,
Useful stuff, as always.
Just one quibble; the grow bag Curzio is using has a (top) surface area of 7 square feet. ( 18 inch diameter.) And the top is the only surface that counts, since that is the only surface to grow leaves from. Thus 10 pounds well ABOVE the theoretic 1/2 pound per square foot limit.
My proposed tower has a diameter of 4 feet.
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Post by Joseph Lofthouse on Mar 28, 2016 23:30:23 GMT -5
I'm including the sun-ward side of the tower, since with a layered tower, the leaves would stick out of the sides as well. You may want to include in your calculations the shading of the leaves lower on the tower by the leaves higher up on the tower... At mid-summer in Denver, the sun's angle at mid-day is what? around 73 degrees above the horizon. I suppose that amounts to about 70% shading... During the potato growing season, the sun rises in the North East, and sets in the North West, which means that all sides of the tower get sunlight during a day. You might also consider subtracting from the available sunlight the shading that the tower causes on the leaves hanging out the sides of the tower. Basically the leaves growing out of the sides of the tower are in the shade of the tower for 50% of the day. And then additionally shaded by the leaves higher up in the tower.
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Post by gilbert on Mar 29, 2016 12:27:42 GMT -5
THE GREAT NUMBERS GAME
So here we go; let's run all the numbers.
The Kenosha potato project is able to get more then a pound of potato per square foot. So we will use a pound per foot as the norm. I have a tower with a four foot diameter, so the top has a square footage of 2 x 2 x pi = 12.5 square feet.
The side of the tower has a surface area of 4 x pi x 4 = 50 square feet.
Total square footage = 62.5 square feet.
The 50 feet is only at 30% potential, so it is as if it was only 15 square feet.
Final Square footage = 27.5 square feet.
So my tower should be able to produce roughly 30 pounds of potatoes, especially since I'm not sure the shade will actually cut down that much on the photo synthesis on the sides. Here in Colorado the available light and heat overwhelm the photosynthetic capacity pretty quickly. So I think that the partially shaded sides would produce at a slower rate, but for a longer period then the full sun leaves on the top.
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Post by gilbert on Mar 29, 2016 12:33:21 GMT -5
A point brought up by Nathan;
Towers spaced close together would shade one another, thus limiting the benefit of leaves sticking out of the sides.
This is a valid point. In this case, the tower is simply "stealing space" not making more efficient use of space, and we should count in the shaded area as used by the tower, since it could have been used by other plants.
However, we could set it up that the shaded area was pavement, etc. or so that widely spaced lines of towers shade cool weather crops such as lettuce on the ground in between.
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Post by gilbert on Mar 29, 2016 12:35:19 GMT -5
A question:
Nathan says:
At this stage I'm just trying to see which ones set tubers high. Would this be a trait which shows up in the first year, or do I have to wait till the second year?
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Post by gilbert on Apr 1, 2016 21:22:07 GMT -5
My TPS are sprouting! The Survive and thrive are coming up. The heat didn't seem to make a difference, though to tell the truth it didn't get heated much. The ones in the starch are not sprouting yet.
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Post by gilbert on Apr 1, 2016 21:36:41 GMT -5
While shopping for seed potatoes, I ran across a lady who had a lot to say about potato towers. She uses a collapsible Tyvek tower/ planter, round, about three feet tall and a foot and a half across, tan colored, with drainage holes in the bottom. Potatoes are planted two inches from the bottom; she uses both early and late varieties. They are hilled diligently every time they grow a bit above the soil line. Potato seed pieces are planted "about every six inches"; I guess that could mean anything from 3 to 6 or so pieces in a tower. She cuts them by eyes; e.g., she does not care how small they get, but cuts so that each has only one eye. She only uses pure compost to plant in, and gets a better yield then she used to when she mixed more inert materials into it. She says that when she collapses it there are potatoes on all levels.
There are a lot of unknowns; she talked with her hands, so sizes, etc. are approximate. She buys commercial seed potatoes, and has used several different varieties including late seasons and fingerlings, but I don't have a hard list of types. The compost is out of her compost bin; who knows what exactly it is like. I didn't think to ask what kind of fertilizer she uses, if any.
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Post by paquebot on Apr 1, 2016 23:06:04 GMT -5
Gilbert, stop to think what that lady is doing. That method is common. She is planting conventionally but at different levels. You already know that a potato vine will keep on growing and growing as long as it is hilled. The lady starts another layer where the production zone of the previous one stops. That is done by planting the first one in the center. The next one may be at 12 o'clock between the first plant and the edge. Third may be at 3 o'clock, fourth at 6 o'clock, and fifth at 9 o'clock. As long as there are enough nutrients in whatever is added to each layer, each new plant is not competing with the previous one.
Martin
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Post by nathanp on Apr 2, 2016 6:53:39 GMT -5
linkFound this paper on potato planting density and yield.
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Post by gilbert on Apr 2, 2016 13:05:23 GMT -5
Hello Martin,
As far as I could tell, she only put potatoes in the bottom of the tower. Then again, maybe I missed something.
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Post by nathanp on Apr 2, 2016 14:27:58 GMT -5
Sounds like an April Fool's joke.
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Post by paquebot on Apr 2, 2016 15:27:46 GMT -5
Hello Martin, As far as I could tell, she only put potatoes in the bottom of the tower. Then again, maybe I missed something. I would say that she starts out with one potato near the bottom and then adds another every 6" as they grow. That system does work and there should be information on the Internet attesting to it. That's why she is using compost to fill the container as they grow. The medium is not just for the tubers to form but to feed the next plant. Since you are bent on growing potatoes vertically, try it and you'll find that it works. Most use a square tower so that there is the center and 4 corners for orientation of the 5 plants. A piece with a single eye is used so that there's just one plant. That assures that there is room for 5 plants plus maximum production per plant. Dar Jones disbelieves this but most common potatoes will only produce 3 or 4 tubers per plant. The minute that anyone reads that results in a big NO because they easily get a dozen tubers per hill. Yes, dozen per hill which has 4 or more plants. If 4 eyes activate and produce 4 sprouts, each becomes a separate plant with its own separate root system and stolons. There are companies which sell eyes which are a great way to reduce the cost of shipping. Drawback is that you end up with only 25 plants. However, the tubers produced will be larger than if there were a cluster of plants. In average soil, there will be 3 or 4 tubers. One will be large, one medium, and one small. If there are more than enough nutrients, the medium becomes large, the small becomes medium, and another small is formed. I bought eyes from Gurney's the first time that I ever saw them offered in 1990. 25 eyes each of Kennebec and Red Norland both easily filled 5-gallon pails and not much more than 75 tubers each and all were big ones. Yet they started out in a bag that nicely fit in one hand. Martin
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Post by gilbert on Apr 2, 2016 18:13:01 GMT -5
Interesting stuff, I'll look into it.
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