How a Potato Plant Grows.

[Durgan]

Potato Test Box
Note: Potato blight (Phytophthora infestans) struck my area for the first time this year. Only a few of my new tubers were affected. We had a wet, cool Summer. In fact, the worst Summer that I have encountered. The Summer that wasn't. So much for Global Warming in the short term.

http://www.durgan.org/URL/?TestBox 25 April 2009 Potato Test Box
A test to determine if potatoes grow from the stem of the plant. The box makes hilling relatively easy. At the end of the season the boards will be removed carefully, starting from the top and the actions photographed. One potato, Red Pontiac, was chosen. The potato is hilled daily, and will be continued until blossoms start to form.

http://www.durgan.org/URL/?PotatoU 27 May 2009 Potato Test Box
Pictures depicting growth and hilling procedure.

http://www.durgan.org/URL/?TESTP 2 June 2009 Another four inch board added to the box and the potato hilled.

http://www.durgan.org/URL/?TestBoxP 7 June 2009 Test Potato Box
Another four inch board added to the height.

http://www.durgan.org/URL/?EIFPD 17 August 2009 Potato Test Box
The seed potato is about six inches below the bottom of the box. The plant was carefully hilled often as the stalk grew. Hilling ceased when the flowers started to form. According to some there should be potatoes along stolens growing all along the stem. Experience has indicated that this is simply not the case. It will be a few weeks before the upper boards are removed and pictures supplied at each removal.

http://www.durgan.org/URL/?ZELNG 21 August 2009 How a Potato Plant Grows
Potato growing test box was opened today. The pictures literally speak for themselves. Clearly there is no advantage in carrying out excessive hilling when growing potatoes. The purpose of hlling is to insure the tubers are covered. For comparison one Pontiac Red was dug in the same row, which was almost identical to the test box potato in appearance.

[MKG]

Just as I thought.

Thanks for the test, Durgan.

Mike

[Millymollymandy]

Oh, that's the opposite to what I thought the end results would be and my experience with earthing up spuds!

Mine don't stay where I plant them but seem to push themselves up the more I earth them up and there are still green spuds poking through the soil and the original tuber is above where I planted it.

So next year no earthing up anymore as it is a waste of time and it is impossible to water them like that anyway!

[Durgan]

Oh, that's the opposite to what I thought the end results would be and my experience with earthing up spuds!

Mine don't stay where I plant them but seem to push themselves up the more I earth them up and there are still green spuds poking through the soil and the original tuber is above where I planted it.

So next year no earthing up anymore as it is a waste of time and it is impossible to water them like that anyway!

Earthing up is essential, particularly if the potato is grown in a confined space. The new tubers are all above the seed potato, if grown without restriction. New tubers are in a circle just above the seed potato, and do push a bit trying to obtain space to grow.The new tubers must be covered to prevent light from forming solanine, which is indicated by green potatoes, which should not be ingested. The green can be cut away to some degree, and the remainder of the potato utilized.

I did the experiment, since many people believe new tubers grow from the stem as tomatoes do, and I knew from observation that this was not the case. There are still people who dispute the evidence.

The point is, only hill enough to keep new tubers covered to eliminate light.

[Millymollymandy]

But as I pointed out, mine, now matter how many times I earth them up, still produce spuds at the top which poke out of the soil!

There was a discussion about how to grow potatoes here a bit earlier and Jandra never earths hers up either, just plants them deeper in the soil then fills it back to level. That's what I'm going to do because it will save me a lot of work and as I said, I can't water them and it is very dry here in summer and they all get scab. Plus earthing up makes it very difficult to walk up and down the rows to pick off colorado beetle, as there's only room to put one foot in front of the other in a deep narrow trench!

Maybe if you did that experiment with different varieties of potatoes you might find they responded differently? Or do the experiment with a row of spuds growing in the ground, earthed up traditionally, where you can't water because they are growing out of the top of a triangular shaped ridge, rather than in a square box with a flat soil surface which can be watered. Maybe my lack of water is why mine push themselves up and produce spuds near the top?

[Durgan]

But as I pointed out, mine, now matter how many times I earth them up, still produce spuds at the top which poke out of the soil!

There was a discussion about how to grow potatoes here a bit earlier and Jandra never earths hers up either, just plants them deeper in the soil then fills it back to level. That's what I'm going to do because it will save me a lot of work and as I said, I can't water them and it is very dry here in summer and they all get scab. Plus earthing up makes it very difficult to walk up and down the rows to pick off colorado beetle, as there's only room to put one foot in front of the other in a deep narrow trench!

Maybe if you did that experiment with different varieties of potatoes you might find they responded differently? Or do the experiment with a row of spuds growing in the ground, earthed up traditionally, where you can't water because they are growing out of the top of a triangular shaped ridge, rather than in a square box with a flat soil surface which can be watered. Maybe my lack of water is why mine push themselves up and produce spuds near the top?

I can't identify with your problem. Here is how I plant potatoes. Having green colored potatoes is a waste of time and effort. New tubers must be protected from light, when growing and indeed after harvest.

http://www.durgan.org/URL/?Potatoes 13 April 2009 Potatoes planted. Today about 60 more potatoes were planted. Row width is two feet and spacing in the row is 12 inches. Depth is about four inches. Types are Superior (white), Russian Blue, Unknown from 2008 stock, Four store bought to complete a row. Total in the patch is about 80 potatoes.

http://www.durgan.org/URL/?Hilling 17 May 2009 First Potato Hilling. Quality compost was added to the area around the potatoes. This will be used for the final hilling, when the stalks are about a foot or more high.

http://www.durgan.org/URL/?PotatoH 27 May 2009 Last hilling of Potatoes.
The four rows of potatoes were hilled. This gives a depth of six to eight inches of soil above the seed potato. In the valley formed after hilling, the space was filled with compost. This was not necessary, but the compost was available and it will supply nutrients.

I did have a few potqatoes that became exposed, but when seen, I simply kicked a bit of soil to cover. I also could have left more space between rows and implemented conventional hilling.

Here is how I water the plants, if necessary.
Watering Plant Roots
http://www.durgan.org/URL/?WandW 28 May 2009 Watering Plant Roots.
This method gets water to the root area of the plants. The hydraulic effect of the water makes pushing the wand into the ground effortless. The device is made by cutting off the end of a typical water garden wand as sold in most hardware stores.

[Millymollymandy]

Interesting as that's pretty much how I grow my spuds although I try not to water with mains water but use my water butt water for the veg patch. One year I got the seep hose in place at the right time and that worked (although of course it is using mains water) but usually by the time I need to water it is too late to get a bendy seep hose in place around leafy plants!

There's another thread about potatoes at the moment and it seems I'm not the only one with spuds that push themselves up and/or expose the tubers to the light. When all the leafy growth is there it is impossible to get along the rows and see if any are green until it comes time to dig them up!

Anyway a few lost green spuds is no problem as I always have far too many potatoes which don't store long enough. It's impossible to buy only a small amount of seed potatoes and 25 (ish) plants is way too many for 2 people even if they do last as long as 6 months. I reckon I have a good year's worth of spuds left!

[Alienor60]

There are two tricks for potatoes in a tower: the temperature during chitting has to be low (but at least 200 lux of light!), around 5-8°C, to produce lots of medium potatoes instead of only few oversized, and the main shoot must be broken before planting them - this supports the building of side shoots. Perfect shoots are max. 10mm, strong and dark.
So you can get up to 3 feet of potatoes in one high container (okay, the youngest are very tiny at harvest, around 5mm -2cm). My best harvest from a single 48 ltr container with one potato was 4,6kg (about 400g were in smallest sizes, like peas..