Potato Spacing

fortyonenorth · April 14, 2011

My potato bed is 35 feet long and 3 1/2 feet wide. Should I plant a single row down the middle or can I get away with planting two rows? I'm planning on 12" spacing.

kath · April 14, 2011

My potato rows are only 12' long, so I have quite a few, and I often plant pairs of rows as close as 2 to 2 1/2' apart and then don't make a path in between those closer rows. My yields and the size of the potatoes seem as good as when I space them 3 to 3 1/2' apart with a path between each row. The limiting factor seems to be having enough soil available to hill adequately, but that can be accomplished with the use of soil + mulch, too. I also space them 10-12" apart in the rows.

fortyonenorth · April 14, 2011

Thanks Kath. I realize now that if I planted a single strip I'd only have enough room for 35 tubers. I have exactly 70 pieces (what luck!) so I'll do two rows spaced about 2 feet apart.

**Tom Wagner** · April 14, 2011

Fortyonenorth,

Since this is your second year for growing potatoes...your question is quite valid.

As I understand it.....your bed is 42 inches wide. What is around the bed? Is it grass or some kind of walkway or is it next to some other crops which may impede the light required to grow the vines to a lush canopy? A single row would be wasteful in my opinion unless you have other crops you need to provide light for full use.

My assumption is that you have a raised bed...unless otherwise noted. Here is what I would do....I would make two rows...about two ft apart with 9 inches on either side. Rather than plant at 12 inch spacing....I would go up to 14 inches and alternate the spacing from a square block spacing to a herringbone such as
-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
which would be thirty tuber sets per row. 60 sets for the 35 ft. row.

This offset spacing would encourage the potato vines to grow where the least competition for light would be. The potato vines would close the row at 7" across and would close/coalesce the two rows when it has grown to 12.5 inches wide, after which point most of the growth would go toward the outside of the rows. The canopy of the individual potato plant can grow twice the size after it reaches row coalescence and the bed of potatoes will likely expand to cover slightly more than the 42 inch bed by a few inches. Since no competition for light occurs on the outside of the rows....a full yield could be expected.

I suggested mulching the center of the row with alfalfa hay....loosely pulled apart and billow up the center of the row about the time the plants are 6 inches high. This high center will delay the coalescing a few days longer encouraging the outward bulking of the vines. But before you mulch...pull the soil out of the middle towards the vines leaving a deep trench. This will avoid the potato roots from competing with the adjoining row so much. The alfalfa hay will release valuable nutrients to the center of the row and will keep the temps down in your Mid-West summer heat, and will void weed comp.

If you don't have access to alfalfa hay, try to find some sweet clover, red clover, comfrey to fresh cut and lay in the middle row.

Tom Wagner

fortyonenorth · April 14, 2011

Thanks Tom. Yes, this is more or less a raised bed. On one side is the driveway on the other, is a retaining wall. So, they get the entire 42" to themselves, but nothing more

I like the herringbone idea and think I'll go with that.

Last year's potato crop was disappointing and I'm looking forward to better results this year. In addition to the alfalfa hay, do you recommend any fertilizing throughout the season?

**Tom Wagner** · April 15, 2011

I have several plots where I plant potatoes and I rotate the actual sites so that no potatoes were planted in the spots ever or at least not during the last three years.

I have a habit of making a row, plant the whole or cut tubers, and then follow with a dusting down the row with a bag of premixed ingredients. That has been using compost with a host of things like worm castings, bone meal, blood meal, cottonseed meal, greensand, kelp meal, alfalfa meal, rock phosphate, fish meal, dolomite lime, gypsum, humic shale, mycorrhizal inoculants, wood ashes, and a few other ingredients. Following up later in the season with between rows with composted manures, feather-meal, etc., has been one of my habits.

Everything I do is organic and most of these materials are bought in 50 lb. units. I feed the potatoes this way in order to get full mineralization of the soil and to slowly feed the plants so that they bloom well for me, and set berries, and have healthy tubers to eat.

It may sound like I over fertilize the potatoes but I really don't. Mostly I am getting a jump start for the early growth and allow the well rooted potato vines to search and seek for nutrients later on.

Tom Wagner

fortyonenorth · April 15, 2011

I think we're on the same page with regard to the fertilization.

Per my soil test, I applied soft rock phosphate, ag sulfur, and trace amounts of boron, manganese sulfate, copper sulfate and zinc sulfate - plus a generous amount of greensand and dried kelp. In about a week I'm going to drench with a tonic of mycos, humic acid and molasses. My calcium, magnesium and potassium levels were good.

The one very gray area for me is Nitrogen. I don't test for N, but my guess is that my soil is pretty lean. Would the equivalent of 100 lb/acre be adequate?

**Tom Wagner** · April 16, 2011

I can't think of actual nitrogen per acre anymore...been away from farming hundreds of acres for years....now just working with plots. Even though a crop of potatoes will take more than 100 lbs. of nitrogen out of the soil per acre..I have to go back to your 42 inch by 35 ft. plot of about 122 sq. ft.

The old rule of using composted manure at the rate of 1 pound per 1 sq ft......
could be used but I would just use one bag of composted manure in your plot.
And even then, I would use less than half that and band it along side the rows of potatoes and work it in. As the potatoes grow the hilling up will bring that soil mix around the potatoes and slowly release the nutrients into the root zone following rain or irrigation. Therefore, a 40 lb. bag might do you for now and maybe another bag as a follow up when the potatoes bloom. Most steer manure is around a 1-1-1 ratio of NPK. That means for you plot with one bag of it applied you are getting less than one half pound of actual nitrogen.

One acre is 43,560 sq ft. You have 122 sq ft. That is 1/357 of an acre. Trying to do the math is mind boggling.... sometimes. Organic gardening with amendments allows one to optimize a piece of ground with rather profound results. If your first year in growing in that area did not perform well, a continued organic approach will eventually promote mineralization, boost the organic matter and all the organisms necessitate to use further NPK additions.

April 14, 2011	#1
fortyonenorth Tomatovillian™ Join Date: Jan 2010 Location: NW Indiana Posts: 1,150	Potato Spacing My potato bed is 35 feet long and 3 1/2 feet wide. Should I plant a single row down the middle or can I get away with planting two rows? I'm planning on 12" spacing.

April 14, 2011	#2
kath Tomatovillian™ Join Date: Jan 2010 Location: zone 6b, PA Posts: 5,664	My potato rows are only 12' long, so I have quite a few, and I often plant pairs of rows as close as 2 to 2 1/2' apart and then don't make a path in between those closer rows. My yields and the size of the potatoes seem as good as when I space them 3 to 3 1/2' apart with a path between each row. The limiting factor seems to be having enough soil available to hill adequately, but that can be accomplished with the use of soil + mulch, too. I also space them 10-12" apart in the rows.

April 14, 2011	#4
Tom Wagner Crosstalk™ Forum Moderator Join Date: Aug 2006 Location: 8407 18th Ave West 7-203 Everett, Washington 98204 Posts: 1,157	Fortyonenorth, Since this is your second year for growing potatoes...your question is quite valid. As I understand it.....your bed is 42 inches wide. What is around the bed? Is it grass or some kind of walkway or is it next to some other crops which may impede the light required to grow the vines to a lush canopy? A single row would be wasteful in my opinion unless you have other crops you need to provide light for full use. My assumption is that you have a raised bed...unless otherwise noted. Here is what I would do....I would make two rows...about two ft apart with 9 inches on either side. Rather than plant at 12 inch spacing....I would go up to 14 inches and alternate the spacing from a square block spacing to a herringbone such as -_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_ which would be thirty tuber sets per row. 60 sets for the 35 ft. row. This offset spacing would encourage the potato vines to grow where the least competition for light would be. The potato vines would close the row at 7" across and would close/coalesce the two rows when it has grown to 12.5 inches wide, after which point most of the growth would go toward the outside of the rows. The canopy of the individual potato plant can grow twice the size after it reaches row coalescence and the bed of potatoes will likely expand to cover slightly more than the 42 inch bed by a few inches. Since no competition for light occurs on the outside of the rows....a full yield could be expected. I suggested mulching the center of the row with alfalfa hay....loosely pulled apart and billow up the center of the row about the time the plants are 6 inches high. This high center will delay the coalescing a few days longer encouraging the outward bulking of the vines. But before you mulch...pull the soil out of the middle towards the vines leaving a deep trench. This will avoid the potato roots from competing with the adjoining row so much. The alfalfa hay will release valuable nutrients to the center of the row and will keep the temps down in your Mid-West summer heat, and will void weed comp. If you don't have access to alfalfa hay, try to find some sweet clover, red clover, comfrey to fresh cut and lay in the middle row. Tom Wagner

April 15, 2011	#6
Tom Wagner Crosstalk™ Forum Moderator Join Date: Aug 2006 Location: 8407 18th Ave West 7-203 Everett, Washington 98204 Posts: 1,157	I have several plots where I plant potatoes and I rotate the actual sites so that no potatoes were planted in the spots ever or at least not during the last three years. I have a habit of making a row, plant the whole or cut tubers, and then follow with a dusting down the row with a bag of premixed ingredients. That has been using compost with a host of things like worm castings, bone meal, blood meal, cottonseed meal, greensand, kelp meal, alfalfa meal, rock phosphate, fish meal, dolomite lime, gypsum, humic shale, mycorrhizal inoculants, wood ashes, and a few other ingredients. Following up later in the season with between rows with composted manures, feather-meal, etc., has been one of my habits. Everything I do is organic and most of these materials are bought in 50 lb. units. I feed the potatoes this way in order to get full mineralization of the soil and to slowly feed the plants so that they bloom well for me, and set berries, and have healthy tubers to eat. It may sound like I over fertilize the potatoes but I really don't. Mostly I am getting a jump start for the early growth and allow the well rooted potato vines to search and seek for nutrients later on. Tom Wagner

April 16, 2011	#8
Tom Wagner Crosstalk™ Forum Moderator Join Date: Aug 2006 Location: 8407 18th Ave West 7-203 Everett, Washington 98204 Posts: 1,157	I can't think of actual nitrogen per acre anymore...been away from farming hundreds of acres for years....now just working with plots. Even though a crop of potatoes will take more than 100 lbs. of nitrogen out of the soil per acre..I have to go back to your 42 inch by 35 ft. plot of about 122 sq. ft. The old rule of using composted manure at the rate of 1 pound per 1 sq ft...... could be used but I would just use one bag of composted manure in your plot. And even then, I would use less than half that and band it along side the rows of potatoes and work it in. As the potatoes grow the hilling up will bring that soil mix around the potatoes and slowly release the nutrients into the root zone following rain or irrigation. Therefore, a 40 lb. bag might do you for now and maybe another bag as a follow up when the potatoes bloom. Most steer manure is around a 1-1-1 ratio of NPK. That means for you plot with one bag of it applied you are getting less than one half pound of actual nitrogen. One acre is 43,560 sq ft. You have 122 sq ft. That is 1/357 of an acre. Trying to do the math is mind boggling.... sometimes. Organic gardening with amendments allows one to optimize a piece of ground with rather profound results. If your first year in growing in that area did not perform well, a continued organic approach will eventually promote mineralization, boost the organic matter and all the organisms necessitate to use further NPK additions.