Best yield - should you cut seed potatoes

Hi,

I am not sure the best place for this topic, but this seems an option.

I am about to establish a wood-chip garden on bare soil, and also have 1.5kg of seed potatoes looking at me on our book case waiting to be planted out (it is spring here in New Zealand).   There are 16 which range between 50-120g (2-4oz).  I plan to keep covering them with wood chip, and spread out sideways later.   I have 8 acres farmland, and about 200 cubic metres of well composted wood chip with more arriving on a regular basis.  

I am trying to decide whether it is better to plant the potatoes whole or to cut them into pieces.  If I cut, I won't be treating with chemicals after.    

WE are in a very temperate climate near the sea.  We have 6+ months of frost free weather ahead at least, and summers average a maximum high of 22C   (71F).  So we have a long growing season ahead of us.

If I cut, we will get more plants, but will each plant give less potatoes?  What would be best n a hgh nutrient environment?

We have always cut our seed potato based on how many eyes are on the potato.  As far as I can remember we get one plant per eye and the yield is per plant.

I added your thread to the Plants forum to give you more exposure.

Here is a thread that might offer some help:

https://permies.com/t/55173/Permaculture-potato-growing

The rule of thumb I hear a lot is that each piece should have two eyes. I always assumed one was for the plant, and the other for the root, but I never asked.

I have always cut my seed potatoes unless there were more than I had space to plant.

Theoretically, the more starch available, the more the plant can grow without need for external food, but I have never noticed much of a difference in yield or plant size. Perhaps beyond a certain point, the starches are simply utilised by something else in the soil.

You could, perhaps, do a small-scale trial. Divide only what seed potatoes are necessary for the amount of space available to plant, and plant some uncut. Just keep track of which are where, and take note of the comparative plant growth rates, size, and yield, and get back to us at the end of the season.

Otherwise, let us know how you proceed, and good luck.

-CK

It's like Anne says, one eye = 1 potato plant so cutting a seed potato so each piece has one eye means better spacing for more potato production than if you were to just plant whole potatoes.

It also helps to plant them in a  trench, then as the plant grows up you can add more supporting soil, wood chips, rotting straw around the plant and you will get more yield that way (here in the south we call that mounding).

I've grown potatoes in the soil, in containers in soil, in containers in wood chips and straw mixed together, my best results were in soil but the year I did the wood chips and straw mix, it was hard to keep enough water on them so the plants didn't fare well.

Last fall I threw whole potatoes on the ground and covered them with Hay and mulch.  When I harvested in spring I left the biggest potatoes in the ground.  I don't know if this will work but I'm trying it.  I'd like taters to run on autopilot.

I've grown potatoes from store potatoes. But that was back in the days before they treated them to keep them from sprouting. I used to take a bag of spuds and a knife. I cut the potatoes and let them fall into the ground. They grew quite well, thank you.

If I were selling seed potatoes I advise you to cut them so that two eyes were on each seed piece, I'd sell more seed potatoes. I've read recommendations that you cut them so that three eyes were on each of the spud seeds. I would raise the question whether those who suggest multiple eyes aren't treating their seed potatoes? I remember potatoes with sprouts a foot or more long. So hard to deal with. Maybe just a little treatment?

Next year I plan on growing potatoes again. My plans are to plant a couple varieties of "seed potatoes" and some organic potatoes from the store. I'll make sure the rows are totally filled out with the organic store potatoes.

I know this is an old post, and it is seems unlikely that there will be more conclusive answers now than before, but just out of curiosity - has anyone here really tried a side by side comparison? Here in Norway it seems to be standard practice to plant whole seed potatoes. The idea that "one eye equals one plant" may be true, but I am pretty sure several eyes also equals one plant - I have always planted whole seed potatoes, and even if they have several growth points/eyes/sprouts, these never seem to result in separate plants. When they are pulled, all stems and all roots join in one point, where the remains of the seed potato are found if present at all.
Whether a plant growing from one eye on a cut seed potato piece will be as productive as a plant growing from several eyes on a whole seed potato, I do not really know, but intuitively several growth points seems likely to result in more leaf area (at least at the start of the season), resulting in faster plant development. Maybe this possible initial difference actually doesn't matter in the end? If there is a difference, it may be more noticeable where growing seasons are short, or weed pressure is higher?
Anyway, unless seed potatoes become really expensive I wouldn't want to cut them. It is extra work, after all, and must result in at least some increased risk of disease or rot.
Actually, maybe differences in  seed and labor costs and/or diseases present are the real reasons why seed potatoes are routinely cut in some parts of the world but not others.

The way I look at this is why have one plant when you can have ten?

I cut mine and got basically no yield. Tried again without cutting and got a decent yield. Both times it was with store bought potatoes that started to sprout.

Anne Miller wrote:The way I look at this is why have one plant when you can have ten?

If it works for you, why not have ten indeed! I may actually try a side by side comparison next season (too late for this year), I am really curious now. Like I said, I *believe* whole seed potatoes may result in plants that grow faster at the start of the season, which at the very least should give them an edge over any weeds.

On my list for next year! Just need to figure out how much area I can plant with potatoes. Would be an even better experiment with several cultivars..

I have assumed that seed potatoes here in Norway are never cut, but I have to admit I don't actually know what large scale growers do. I've just never seen or heard of anyone doing it in a gardening context, and assume that it is too time consuming and expensive (labor cost) on a commercial farm. Neither of which really say anything of the actual ability of cut seed potatoes to grow productive plants.

The potato farms I worked at in Maine sorted out all the small potatoes for seed and the larger ones for food. They sold both.  So I eat large potatoes and replant small ones. The size and number of potatoes resulting seems more dependent on consistency of moisture in the soil though larger seed makes larger plants at the start.
Back to my lasagna planning, the lost little ones that came up in the greenhouse in February are close to harvest, some were pea size.  The lasagna is a layer of compost to hold water and feed, layer of sand to protect the skin of potatoes from scab, layer of seed, layer of sand, layer of mulch.

This year for the first time , we cut our seed potatoes. We ended up having way too many.
And after cutting, the potatoes went bad quite quickly. I had read on internet that you had to let the cut
potatoes sit for a few days before planting. But that does not seem a good idea as they were going bad.
I was also wondering if we would have the same yield. In previous years we put in whole potatoes.
I probably will have many potato plants in the compost as we threw the left over pieces there.

I hope the pieces will yield!
I will give lots of mulch and urine as a support. I don't have a lot of compost left. But I have compost teas of nettle and I will make of comfrey also. I have some big comfrey plants. Soon I will cut them.
Will I get more fertility by putting the comfrey leaves around the potatoes or by first making compost tea out of the comfrey plants?

I am sorry to hear you got no yield, Nick. But other people do seem to have yield with cut potatoes.
I will have to wait and see!

I've experimented with both and found it made no difference to the amount harvested.  So I cut mine if there are two or more eyes growing, otherwise, just toss them in whole.  If we cut, we let them sit no more than a couple of hours in the cool shade.  At most 12 hours.  If there is still hard frost when I plant (which is most years), I don't cut as it can make them more susceptible to frost damage.

The crazy thing is, the next year we experimented with large vs small seed potatoes and the smaller ones had considerably greater yield.  

This is in my climate on those specific years.  It's worth doing an experiment in your own garden for a few years to see which does best in your climate.  But do half one style and half the other so there is a control group to compare against.  

I know you said if you cut them you won't be treating them but you might want to dip the cut side in wood ash. Helps with keeping them from rotting