Permies' Potato experiments

Joylynn Hardesty wrote:
..And look who is peeping out today!

Oh my! That's only just over two weeks from planting. What sort of day time temperatures were you getting in the last half of March?

I’ve been feeling overwhelmed with other stuff and so I put off catching up on this thread. But now I’m back. What is it I’m supposed to be testing with regard to light/dark chitting? I don’t normally do anything special to get my tubers ready. I pull them out of the dark cellar, they have white sprouts, I plant them, they grow. I just pulled a couple handfuls out put them in a cardboard box and moved them into a plant tent with very bright light. All I need to do is test my normal white sprouts against sprouts that have been allowed to green, then I think I’m good. I’ll plant in a month or so. But if I should be doing something else, or additional, someone, please let me know. :-)

ETA: I'll grow the ones now under lights near a similar batch of tubers from the cellar, using all the same materials and methods, and hopefully any differences will be readily evident.

Christopher Weeks wrote:I’ve been feeling overwhelmed with other stuff and so I put off catching up on this thread. But now I’m back. What is it I’m supposed to be testing with regard to light/dark chitting? I don’t normally do anything special to get my tubers ready. I pull them out of the dark cellar, they have white sprouts, I plant them, they grow. I just pulled a couple handfuls out put them in a cardboard box and moved them into a plant tent with very bright light. All I need to do is test my normal white sprouts against sprouts that have been allowed to green, then I think I’m good. I’ll plant in a month or so. But if I should be doing something else, or additional, someone, please let me know. :-)

ETA: I'll grow the ones now under lights near a similar batch of tubers from the cellar, using all the same materials and methods, and hopefully any differences will be readily evident.

Thanks for your dedication in doing this experiment, Christopher. Potatoes stay in their dormant state best by being kept cold [like just above freezing, and in the dark], with fairly high humidity. In our area, "commercial" potatoes are kept in large sheds where humidity is maintained at 95%.
Wisconsin has a central area that is very sandy and where potatoes grow very well. Commercial growers do not chit their potatoes [keeping only 1-2 eyes so the whole potato can give more energy to the plant]. But that might be because of the work required, on a commercial scale to chit tons of potatoes!
They do tend to grow *determinate* potatoes, which grow their tubers only in the top 6" of the soil. Those do not take as long to mature, and that is an important consideration when you need to take the crop to market quickly. At home, we can do better by growing *indeterminate* potatoes in deep containers. Those will grow tubers on the entire length of the vine. Indeterminate potatoes take longer to grow.
Other than that, try to raise the P in the NPK: Phosphorus is what will grow bigger tubers. It can be done with a generous amount of bonemeal:  Chicken and horse manure, bone meal, fish emulsion and rock phosphate are all good sources of phosphorus for plants.
Timing of the fertilization is also important: Potatoes "bulk"  around 40 days after planting, and that is when they should get this input of extra phosphorus. So count on putting that nutrient, in whichever form you choose, about 40 days after planting. Make a note in your calendar, then on day 40, add a generous amount of bone meal and water well.
The ideal PH is 5 to 6.5
When you look at the number of variables to get good tubers in great quantity, I would not fret about growing them under light, as electricity is expensive and probably will not give you the biggest bang for the buck.

I think you've got another variant there Christopher. Your sprouts are already quite long. So my sprouts were short and green, yours will be long and green (hopefully).
But yes, see if there is a growth/yield difference between the spuds planted in your normal way and ones left under lights to go green. I just leave mine on the windowsill since I don't have growlights.

I'm not sure if we'll get enough replications to get a statistically significant result, given we all have slightly different starting points, but I'm finding just that fascinating! All the different ways of storing and growing potatoes!

If I were to guess, I'm thinking your cellar is probably a bit on the warm side for potato storage. I got virtually no growth on my tubers in my workshop (just an uninsulated corrugated steel shed) between harvest in September and bringing them in the house to chit in February. They were not in the dark there though, and that might be a more significant factor.

One experiment of mine is underway. Here is a Papa Chonca that I have buried in sand, and plan to grow the shoots to the point of self sufficiency and then take them off as cuttings. I’m relatively sure they are indeterminate because I threw a pile of weeds—mostly grass—on top of the patch last spring and they grew more luxuriantly and made more tubers into the hill of uprooted weeds.

Another observation is that the potatoes tend to overwinter better when there is a mat of chickweed over them, which seems to insulate the soil.

Nancy wrote:What sort of day time temperatures were you getting in the last half of March?

High temp were ranging between 60 to a couple scattered days in the low 70s. Then today's high was. 50, going down to 37 tonight. Ick.

Joylynn Hardesty wrote:

Nancy wrote:What sort of day time temperatures were you getting in the last half of March?

High temp were ranging between 60 to a couple scattered days in the low 70s. Then today's high was. 50, going down to 37 tonight. Ick.

OK that's like my midsummer temperatures (15-25 degrees Celsius) and now back to what I've got currently (about 5-10 degrees Celsius) I expect the potatoes will be fine, as long as it stays above freezing, although growth will presumably be slower as well.
I think that we will only each be able to see the difference in our own climate, and the chitting may be more significant in cooler climates like mine, than warmer ones like yours. There may also be other factors, like soil moisture and variety of potato that will affect the results.

Maieshe Ljin wrote:One experiment of mine is underway. Here is a Papa Chonca that I have buried in sand, and plan to grow the shoots to the point of self sufficiency and then take them off as cuttings.

That's very interesting Maieshe! I'd be pleased to see the results of this!
I've read that using the eyes or the sprouts is a way of reducing the amount of virus in the potatoes. That's one reason we are told not to save our own potatoes year to year - because the viruses can build up over time and affect the yield and quality. Are you going to compare the sprouts to potatoes grown in the normal way from seed potatoes? It would be interesting (if you were able) to continue sprout and seed potato regrowth, keeping the harvest separate for a few years, to see whether and when you notice an effect.

Potato shoots (stems) are sensitive to freezing temperatures. Symptoms of freeze damage may vary from blackening of the leaf margins (minor damage) to death of all aboveground growth (severe damage). Fortunately, severely damaged potatoes will send up new growth (shoots) within 10 to 14 days
If you know that frost is coming, mulch heavily with straw / blankets etc. until it passes. The ground would have to refreeze to kill potato seeds, chitted or not. After all this warm weather, the cold we are experiencing is slowing down everything, unfortunately.

Nancy Reading wrote:

Joylynn Hardesty wrote:High temp were ranging between 60 to a couple scattered days in the low 70s. Then today's high was. 50, going down to 37 tonight. Ick.

OK that's like my midsummer temperatures (15-25 degrees Celsius) and now back to what I've got currently (about 5-10 degrees Celsius)

And to further emphasize the difference in our growing conditions, because it's been such a warm winter and spring, our temps have been roughly 20F/-7C at night and 40F/4C midafternoon, but the ten-day forecast shows a significant and steady warming and the snowcover is melting fast. (In July, our warmest month, our average max & min are: 80F/27C & 54F/12C.)

Nancy Reading wrote:If I were to guess, I'm thinking your cellar is probably a bit on the warm side for potato storage.

It's 50F/10C right at this moment. During a normal winter -- where we can reach -40 but don't usually, it can almost reach the freezing point. There is only a thin wooden door between that closet and our basement living space, so it really depends on the cold of the surrounding soil. Insulating the door is on our project list, but so is digging/building a better cellar.

Nancy Reading wrote:

Maieshe Ljin wrote:One experiment of mine is underway. Here is a Papa Chonca that I have buried in sand, and plan to grow the shoots to the point of self sufficiency and then take them off as cuttings.

That's very interesting Maieshe! I'd be pleased to see the results of this!
I've read that using the eyes or the sprouts is a way of reducing the amount of virus in the potatoes. That's one reason we are told not to save our own potatoes year to year - because the viruses can build up over time and affect the yield and quality. Are you going to compare the sprouts to potatoes grown in the normal way from seed potatoes? It would be interesting (if you were able) to continue sprout and seed potato regrowth, keeping the harvest separate for a few years, to see whether and when you notice an effect.

Interesting to hear! I didn’t know that. But it makes sense perhaps. My system is too messy to make it very scientifically viable, but I’ll pay attention to which ones do better. I also remember hearing about long term cold storage being used to reduce viruses.  

The natural stratification plus soaking for a few days worked well and the seeds have started germinating! Potato seeds are difficult to germinate: last year I couldn’t get any to sprout.

So far I have found eleven sprouted seeds among the ones gathered from the rotten fruits: three yesterday, four the day before, and another four two days before that. This morning the first two have also emerged from the soil.

I have been keeping the seeds in a small bowl with a low level of water, adding a little whenever it starts evaporating. I think this has been keeping it aerobic enough for germination.

I f oolishly thought that I had more time. Several plants are 10 inches tall. Is it too late to hill them?

When I plant, I dig a long trench and line it with pine needles, put in the sprouted potatoes, cut into sections that all have a sprout or three, and then cover with soil.  The trench with pine needle thing is from Martha Stewart, and has worked well for me.

I've got some preliminary results from my potatoes - chitted in light, dark, and unchitted (from 'fridge). They were planted on 30th March and just yesterday I noticed that they were coming through the soil. There may be a slight tendency for the ones chitted in the dark to have emerged slightly earlier, however I suspect it is not enough to notice. There is more indication that the early potato varieties have sprouted more quickly, since they are all showing now, whereas several of the later cropping varieties still not yet showing above the soil.
The proof is really in the yield I suppose, but I would have expected more of a difference at this stage if there was to be a big difference after a growing season.
I wasn't altogether happy with the development of my sprouts of the 'chitted in light' potatoes when I planted them, so maybe if that was optimised there may have been a noticable difference at this stage.

Tamara Carroll wrote:When I plant, I dig a long trench and line it with pine needles, put in the sprouted potatoes, cut into sections that all have a sprout or three, and then cover with soil.  The trench with pine needle thing is from Martha Stewart, and has worked well for me.

I suppose the pine needles are supposed to help with the soil pH? I've heard that potatoes like more acid soil, or are more likely not to get scab perhaps. Have you tried with and without the needles to see whether it does make a difference?

I've tried both ways, with and without pine needles. Potato plants seem like an easy thing to grow and always seem to want to produce potatoes.

I’m replicating the images I took 32 days ago to show their progress. I was sort of expecting  the white sprouts to die and green sprouts to form on the tubers under light, but instead it seems like the white sprouts turned purple and the tubers are soft and wrinkly in a way the ones in the cellar are not.

I’m starting a potato experiment today. I took six great big boxes, peeled off all the labels and tape, put some paper-pulp packaging in the bottom and covered that with about 4 inches of spoiled hay. Then I put down two spuds in each box and covered them with between six and twelve more inches of spoiled hay. And then a little water. I’ll see what happens!

Almost everyone came up in my potato bags, except my uncut katahdins. The cut ones came up just fine. Today I defoliated and mounded up with a thick layer of straw (Ruth Stout deep mulch method). I saw one very underdeveloped potato near the surface in one of the bags!

I put my experimental potatoes in the ground. I decided to plant them in my wife’s square foot beds because they have the lightest fluffiest soil in our garden. I put them diagonally catty corner in case there’s some difference of light or Neighbors or whatever. So the tubers that have been in the dark, the whole time are in the front right and back left of that one picture and the tubers that were in the light are in the front left and back right. Now I just have to watch for difference in performance.

I start harvesting my potatoes planted last December when the plants turn yellow. Weaker plants die first in late May and early June and some stronger ones are still lush green. Since the spuds were not in straight lines I have to harvest continuously or I will miss a lot of them. This red one I dug up this morning yields 2lbs of spuds.

Nancy Reading wrote:

Ac Baker wrote:The first early purple potatoes .. 'Vitanoire'.

Do you fancy chitting one batch in light and dark to see if it makes a difference to the yield?

Because of the cold, wet Spring we've had in central England, I ended up doing this anyhow:  none of the 'light chitted' potatoes I planted out grew until we finally got much warmer weather for a week in mid-May.

The tubers chatted in the dark tended to have longer, pale sprouts.  Those were also warmer! The tubers chitted in the light had shorter, green-purple chits, but were potentially in significantly cooler conditions.

They all seem to have caught up to the same extent of leafy top growth, about a foot, here in mid-June. We are still barely getting up to our typical summer temperature range (achieving 13 - 18 deg C instead of 17 -21 deg C).

This is such a cool idea!

I've never planted potatoes before, and probably won't be able to due to moving around, but I have an idea for a variable to investigate:  Planting by moon cycles!

All things being equal, apparently it's best to plant tubers on a waning moon, when the sap from plants heads towards the ground, and brassicas on a waxing moon, when things head back upwards.  I know a regular farmer who's about as humbug about astrology as you'd expect, but he says farmers did this in Tennessee when he was over there, because it brought results.

Just an idea for a future date.

-- Jojo

Jojo i have heard that since i was a kid,thats how things were done and it does produce good results.I think everyone now just has to get them in the ground because they are too busy and the end result sometimes is mixed.

Maybe we could try that next year? I gather good Friday was the day for potato planting here, is that a root day?

Nancy, Good Friday was probably just a good opportunity to get things done -- whether or not it's a root day will vary from year to year.  You'd have to consult an ephemeris, or just put 'current moon phase' into a search engine at the given time.  There are more detailed astrological instructions for this sort of thing, because the signs are termed 'barren', 'semi-fruitful' and 'fruitful', which relate to all kinds of fertility.  It depends on how detailed you want to get, and also whether or not a waning moon falls in a fruitful sign at the time you want to plant.  There's some wiggle room, but not much, so it's a matter of chance and picking the best moment available at the time, like most other things!

Just harvested one of the bags, got 6 small-medium purple potatoes. This was a purple potato we found in a free food bin last summer. They only grew in the soil, none in the straw. My farmer friend said that certain varieties are well suited to straw method, and others are not. Will report back on other varieties.

I dug all my potatoes today and the results are ..... inconclusive!
I had four different potatoes and three different chitting conditions. I dug them all and weighed the total weight of each variety/condition that were big enough to be of use. It wasn't practical to weigh each plant unfortunately. Some observations: My early black variety (vitanoire) doesn't like Skye much. I got a poor yeild last year. This summer has been worse - cooler and wetter, slug heaven! Only one of the tubers survived to a harvest - so I didn't include these below. They are beautiful tubers though!
It seemed like the ones chitted in the dark have more slug damaged tubers, but I didn't quantify this, other than as it affected the yield.
The results were (average yield in ounces):

treatment	Pink fir apple (main)	Skye Blue (early main)	shop white early
dark	7	18	2.5
fridge	11.5	49.5	10
light	7.8	14	13

I'm very happy with my "Skye blue" potato and it seems to like my growing conditions. I don't know if it has a true variety name, but I can see why it has been selected to grow locally. It has a nice potato flavour and is quite floury in texture, the colouration makes it interesting too. Dinner tonight included some of the tubers that were most badly damaged and won't store.
Anyone else dug their potatoes yet?

That reminds me—there have been some good results of my experimentation. In general, those potatoes that I grew from seed were all far more happy and vigorous than established varieties. Although Papa Chonca had come up happily last year in many places, they died off early everywhere this year, which makes me think they are susceptible to early blight. The rest of the potatoes are mostly still going. The big pink potato regrew from an unseen tuber as well as growing where I planted it, and I have harvested a few tubers. M— white, the other successful self-sown seed-grown potato, is growing excellently wherever planted or regrowing. I had given a few tubers to a friend to plant; it had started slower than the rest, but is outgrowing all the tubers from established varieties. Maybe I should call them “baroque” (as in an irregular pearl) potatoes, which describes them perfectly. They are off white (snowy on the inside) with splotches of bright purple on the skin; they are very lumpy, and also look as if they might store poorly—some of the potatoes I dug up seemed to already be sprouting, though they were barely ripe when I dug them. The potatoes are mild and good but somewhat bland (last year I tasted them and considered them excellent—may need to let them ripen more), which might indicate a very low solanine content. I wasn’t quite sure where the potato ended and the ghee began so will have to try again after steaming. I haven’t yet tasted the big pink potato systematically.

Baroque potato seems sparse in making berries, although I do see a couple forming. Big pink potato is much more generous. Altogether I think this shines very happily upon the benefit of starting your own potato strains from seed.

Nancy Reading wrote: Some observations: My early black variety (vitanoire) doesn't like Skye much. I got a poor yeild last year. This summer has been worse - cooler and wetter, slug heaven! Only one of the tubers survived to a harvest - so I didn't include these below. They are beautiful tubers though!

My Vitanoire in central England didn't come up until the second week of May, due to cold, wet conditions.  This was true of all chatting methods & planting times. I think it was mostly rot, the slug damage wasn't bad.

Chatter is, this has been the worst year in England for allotments in most people's memory.

Nancy Reading wrote:
I'm very happy with my "Skye blue" potato and it seems to like my growing conditions. I don't know if it has a true variety name, but I can see why it has been selected to grow locally. It has a nice potato flavour and is quite floury in texture, the colouration makes it interesting too.  

I wonder if they are related to the similar-seeming Viking Blue / Purple Viking?

The biggest challenge in the potato world is to grow a heat resistant potatoe.

Potatoes usually wont fruit if the night is not significantly cooler than the day.
Here in Thailand we talk about 34 Celsius Day and 26 Celsius night and only October/November till February/March.

India developed Kufri Lima which is now known as most heat resistant but also these are grewn in the north and cooler areas.

If anyone has found the ultimate heat potato he/she probably will grow a golden Nose too.. ;-)

Challenge is on!

By the way: The picture shows where my wife and I am now.
We got a few years ago real potato seeds from India and a single potato from NE Australia a friend gave us in Thailand on his return.
The Aussie potato started flowering and produced seeds as well, we mixed both breeds..
The outcome was small but at least some fruits were growing.

Ac Baker wrote:I wonder if they are related to the similar-seeming Viking Blue / Purple Viking?

Only in as much as they are both purple skinned potatoes. I believe that purple viking has quite white flesh, whereas the Skye Blue has a definite blue ring inside the flesh.

Purple Viking Potato

Image source from Gardenerspath.com

See Hes wrote:The biggest challenge in trhe potato world is to grow a heat resistant potatoe.

Haha! No chance of me doing that here! although a couple of varieties did set berries, so I may have a go at trying from true potato seed next year.

Yesterday, I dug the four planting areas that I was testing for the light- vs. dark-treatment experiment. My previous posts along that thread are here,
here, and here.

I got ~4.5 lbs from the dark-treated tubers and ~9.25 lbs from the light-treated tubers!

I was expecting the opposite result since the light-treated tubers seemed less vigorous at planting and there wasn't a substantial/obvious difference in fullness and health of the foliage.

However, I'm taking this with a grain of salt as the competition around the plants wasn't controlled for. I might test again next year in a row-crop setting instead.

  I forgot about a bag of potatoes at some point late winter/early spring and they sprouted.  It was late to plant them and I had limited space, but why not try?
 
  I rigged up vertical grow containers with chicken wire and burlap and used compost, partially decomposed dead leaves, and some soil (in no particular ratio or order) to fill & hill them.   I placed one in a garden bed in part shade and it produced a healthy plant with beautiful foliage, Four 4"(10 cm) potatoes and 10 delicious 1 1/2" (4 cm) little ones was the yield from this plant.  It also produced the poisonous fruit on top.
  Two cages were placed at the top of a hill that separates my yard/garden zone from my wooded zone. They were left to fend for themselves (after hilling a few times) after open sky changed to dappled sunlight from the tree canopy filling in.  1 marble from that site.
 I had two 10 gallon planting pots with soil, so I placed the cage inside, (removed some soil)  and hilled up as they grew.   One pot was on the southwest side of my yard and one was at the southeast (sunnier). The southeast produces a couple of 3-inchers  (7 cm) and died early and the southwestern one produced 4 nice sized 'taters with lots of "marbles".
 
 Since this year's potato goal was "Let's see what I can learn",  I declare the experiment a success.
 

I just emptied out the boxes of hay in which I was trying to grow potatoes. They were quite unproductive, so in that sense the experiment was a failure. But I did observe some interesting stuff.

The dark purple tubers grew deep and medium sized while the light red ones grew small and all the way up through the matrix of hay. I’m not sure how to make use of the info, but it was quite distinct.

The squiggly red ones only grew in the box that was heavily colonized by fungi. Weird!

Christopher Weeks wrote:I just emptied out the boxes of hay in which I was trying to grow potatoes. They were quite unproductive, so in that sense the experiment was a failure. But I did observe some interesting stuff.

You got a result - that's not a failed experiment! A negative result is still a result.
It sounds like the light red ones would respond to earthing up, whereas the dark purple ones would not perhaps.

I've just finished eating the last of my non-keeper potatoes. Interestingly the potatoes in the new compost heap (which I never intended to grow) are still going strong. Normally I'd expect the potatoes to be killed by blight by now. This year I hope to harvest those when I turn the compost heap in spring.