Potato questions

[GTIYB]

Hey folks,
I just got some potato tubers from a seed catalog and had some questions:

1. The instructions that came with the tubers said I can either wait until the plants die off to harvest the crop or, if the season is coming to an end and the plant hasn't died back, I can cut the plant back to the ground, wait a few days for the skins to set, then harvest. My question is, does that mean it's okay to let the potato plants flower? Will this effect the flavor of the spuds?

2. It doesn't really matter because I've already planted them but, for future reference, do I water them in when I plant the tubers? The instructions didn't clarify but I assumed that the added moisture would encourage the eyes to put out shoots. Hopefully I didn't just rot all of them... I didn't soak the soil - moistened it similar to how you'd moisten soil for starting seeds.

3. The potatoes are described as "seed potatoes" - does that mean that the plants they grow off of were begun as seeds and not divided tubers? I'm just curious about that one.

Anyway, any general knowledge from experienced potato growers would be greatly appreciated. The variety that I'm growing is a "blue" (I thought it was purple... but the catalog calls them "blue"... not sure if there's a difference....) mid-early season varietal. I live in a coastal, central coast California town. I'm growing two separate lots in my garden of 20 potato plants. I'm also growing 13 potato plants in pots to give away to friends who garden.

Thanks,
Matt

[applestar]

Depending on variety some bloom, some don't, and some bloom MORE and readily set fruit. Your "Blue" variety is likely to bloom purple flowers and set fruit as well. Look for the TPS (True potato seed) thread in seed starting forum. Letting them flower won't affect the tubers, and they can be an indicator for when the tubers will be ready to harvest -- small new potato tubers can be carefully dug and "robbed" without digging up the whole plant about two weeks after they begin to bloom.

That bring me to the "seed potato" question. The tubers are called seed potatoes when they are meant to be planted to grow potato plants for growing. When they are "certified seed potatoes" they have been inspected and certified to be disease free. This is because potatoes sold for eating don't have to be guaranteed plant disease free (which doesn't affect eating qualities -- well they sometimes do but anyway).

[rainbowgardener]

as applestar said about the seed potatoes. It does not mean they were started from seed. Planting the seed will produce a potato vine which by the end of the season will produce a small tuber. The following year mini-tuber can be planted to produce a regular potato.

[jal_ut]

All the potatoes I have planted bloom. Maybe they form fruit, maybe they don't, it doesn't really matter. We are not after the fruit, but the tubers which form on the roots and the flowers and fruit have no bearing on the formation of tubers that I could ever see.

When to harvest potatoes? Any time you have some tubers you can harvest. The new little potatoes are delightful. However if you let them go till the plant dies down, you will get more weight. You can poke in the soil around the plant with a finger and find a tuber and lift it out. I grab a few like this to eat without digging the whole plant so it can make more tubers. The new potatoes are very nice eating.

As the tubers form sometimes they come out of the ground a bit and if the sun hits them they go green and get a bad flavor. That is why we hill up potatoes, to keep the sun off the tubers.

I confess, I have never grown in pots, and can't imagine a potato doing that well in a pot. Perhaps if the pot holds at least 7 gallons, it may work. Do you have any ground? Best to make a small plot in the ground if you can possibly do it. Not sure , but maybe you are just starting a few as gifts in pots? That should work fine if they are then put in the ground. Best of luck.

[feldon30]

Most people don't mess with True Potato Seed -- seeds saved from the dark green berries occasionally produced by potato plants -- because potatoes are tetraploid. This means that they have four sets of chromosomes instead of two. Just saving seeds and planting them, you will have dramatically different results with huge variations as the four sets of chromosomes combine in unexpected and almost completely random ways.

If you plant seeds from a red-skinned potato, you will get all sorts of colors, sizes, and productivity. Many of the potatoes won't be very good, too small, or be susceptible to disease. Out of 100 plants, you might get potatoes from 1 that are worth saving. It's a real crapshoot.

There are a few breeders out there who deal with TPS, most notably Tom Wagner. He has been breeding and stabilizing potatoes for decades. One of the varieties is Skagit Valley Gold but there are many others.

The obvious advantage of TPS is shipping weight. A 1 oz packet of TPS will give you as many potato plants as 50 lbs of seed potatoes. You start TPS indoors in trays about 8 weeks before last frost date, and from a seed half the size of a tomato seed, you get the same type of crop you get from a golf ball-sized tuber.

TPS is used sometimes in Central America and Asia, but it hasn't really caught on in the US... Yet.

[jal_ut]

If you plant seeds from a red-skinned potato, you will get all sorts of colors, sizes, and productivity. Many of the potatoes won't be very good, too small, or be susceptible to disease. Out of 100 plants, you might get potatoes from 1 that are worth saving. It's a real crapshoot.

Yes! This is why we propagate potatoes by vegetative methods rather than seed (true seed). The genetic composition remains the same and future generations will produce tubers like the ones planted. Plant a purple spud, get a purple spud. Have fun!

[jal_ut]

"Seed Potatoes", as mentioned are not seed, but rather a potato tuber. I have bought them as whole potatoes and cut them my self with an eye on each piece, or at times they are sold pre-cut and dipped in something to help keep them. These prepared sets are usually about the size of a ping pong ball.

[feldon30]

"Seed Potatoes", as mentioned are not seed, but rather a potato tuber. I have bought them as whole potatoes and cut them my self with an eye on each piece, or at times they are sold pre-cut and dipped in something to help keep them. These prepared sets are usually about the size of a ping pong ball.

And don't forget to dip the cut pieces of potato in sulfur.

I really think in the next 5 years True Potato Seed (TPS) is going to catch on and more people will be starting potatoes from seeds. When a 1 lb bag of seed can plant an entire field, I think the economics will drive adoption.

Here's a picture from Tom Wagner:

[jal_ut]

I have not grown potatoes from seed. This may be the year. A friend gave me a small packet of potato seeds. Actually I can't believe one can get much from a seed in one year. Perhaps a few small tubers that could be planted the following year for a real crop? Perhaps if one were to start them early like tomatoes you might get something?

[feldon30]

As gardeners, it's been ingrained in us that that seed potato you put in the ground is where all the energy comes from for the potato plant above ground and the potato harvest you get below ground. But when you think about it, a tomato seed can produce an 8 foot tall plant and 30 lbs of fruit without relying on some underground energy store.

TPS takes a time to wrap your head around. I want to try some next year just to see if I can really get as good a harvest out of a tiny seed started indoors as I can from a piece of potato stuck in the dirt.

[jal_ut]

I reckon if you got them started early so you had a fair sized plant to set in the garden they may just do very well. Works for tomatoes. You won't get much though if you plant true potato seed directly in the garden . Too late for me this year, its almost time to be setting them out.

[jal_ut]

"Blue" potatoes: I have seen blue skinned ones, and purple ones that were purplish clear through the flesh.
A friend just gave me a box of "Purple" spuds to plant this season. These are purple clear through. I tasted them and they taste like a potato. I am going to plant them.

[Vanisle_BC]

Around here it's said potatoes should be planted around St Patrick's day - March 17, and our frost-free date is about May 21. What do others feel about planting 2 months before theoretical last frost? I've observed that once the plants emerge, frost will kill them back to ground level but they re-grow. I'm wondering if it would be just as well to plant later; or maybe I'm just too slow in hilling-up?

Huh, did I just answer my own question ?

[rainbowgardener]

We say plant potatoes when the forsythia blooms , which often turns out to be a similar mid-March time . For me that has been about one month earlier than average last frost date . Never had any problems with it .

[Gary350]

One year I planted potatoes 1st of December and covered them with 12" of soil. I never noticed plants on the surface until April and they soon died. I waited a month nothing was growing so I dig into potato hill to found a small crop of potatoes. I cut eyes from about 4 potatoes and got about 35 potatoes 2" to 3" diameter.

[jal_ut]

Vanisle_BC, I think I would plant about May 1 to May 5. By the time they come up you should be pretty much frost free. It does potatoes no good to get the vines frozen down.

[Vanisle_BC]

jal_ut, thanks. I was tending to that conclusion myself - plant later so the emerging plant doesn't face frost. Reminds me of the year I took extreme measures to get my peas off to an early start - and the un-pampered ones, planted a month later, caught up and matured at the same time; or within a couple of days. Things take (their own sweet) time.

Change of subject - did you ever follow through on the idea of growing some true potato seed? I was given some seed and have checked that it's viable; contemplating my next move. I looked at a Tom Wagner video on the subject and I'm doubtful I could come up with the strong sunlight with UV that he says the sprouting seeds demand. Not sure if there's artificial light that would do the job. Isn't there plenty of UV in fluorescents?

[Gary350]

I never have good luck with potatoes part of the problem may be I can not buy seed potatoes until late April and I think they should be planted about first of April. Second week of June we are having 95 and 100 degree weather, I think this is too hot for potatoes. Russets are my favorite but Red Potatoes do better. I plant potatoes like my grandfather showed me but TN soil and weather are both different than IL. Grandpa use to get 200 lbs of potatoes every summer and he replanted his own potatoes for 40 years. Oh well potatoes are cheap at the grocery store.

[imafan26]

Interesting subject. Thanks a lot. I learned quite a bit about growing potatoes.

[sweetiepie]

HaHa, I am usually lucky if the snow is off the garden by May 1 and not still muddy by middle of May. I usually plant them first but not until I can get the garden ready and have always had good luck in my short season. Places are so different, crazy.

[jal_ut]

Vanisle_BC: "Change of subject - did you ever follow through on the idea of growing some true potato seed?"

NO!

[Taiji]

Last year I think I planted my red potatoes around mid February to March 1st, simply because the sprouts were getting so long, I didn't think there would be much of the actual seed potato left if I waited any longer. They came up and made beautiful plants about 8 to 12 inches high, but then got hit with a hard freeze. They did come back pretty well but then got hit again. Finally, they came back and I actually got a good harvest though the plants were riddled with what I think were thrips.
So, as Jal-ut says I don't particularly think the hard freezes do them any good, though they do come back. I don't know if the freezes weakened them. I sprayed with insecticidal soap and neem oil later, but neither one helped. I could see the little devils fly away with the spray, but it didn't seem to phase them, they just came right back. I don't know that they were thrips, local garden center said it was a bad year for them, sounded like that's what I had. My main point is that maybe the hard freezes stressed the plants and took away some of the plants' defenses.
But, having said all that, I have some seed potatoes already and I think I'll plant them pretty quick anyway! My last average frost date is around May 7. I think I'll plant another batch later though too.

[jal_ut]

Here we plant potatoes early May, some time as the corn,squash and beans. The vines are not frost resistant so you want to plant when danger of frost is about past.

[Vanisle_BC]

Opinions differ. I just heard our CBC garden guru Brian Minter on the radio, talking about getting "winter potatoes" - he mentioned Warba - planted now in the B.C. lower mainland.

Incidentally I dislike Warba for eating; very dry when I grew them. But my wife loves them .

[jal_ut]

"Around here it's said potatoes should be planted around St Patrick's day - March 17, and our frost-free date is about May 21. What do others feel about planting 2 months before theoretical last frost?"

I am thinking that planting your potatoes about May 5 would work well. It does potato plants no good to have the vine frozen down.

[Gary350]

When you cut your seed potatoes into pieces with 1 eye how long do you let them dry out before planting them in the garden?

[jal_ut]

"When you cut your seed potatoes into pieces with 1 eye how long do you let them dry out before planting them in the garden?"

I just cut them and go plant them. When cutting potatoes, you know the eyes are pretty close together on the one end of the potato, and then scattered out. It is hard to cut only one eye and have any tater left, so some pieces end up with two or three eyes on them. Doesn't really matter. They all grow. If you plant a whole spud you get probably 7 to ten plants. Each eye produces a plant. Of course these are too crowded and the potatoes you get will be small because of the competition. That is why we want to cut them to spread out the plants so they will make some bigger taters.

[Gary350]

My grandfather use to cut potatoes then let them dry several day but soil and weather in Illinois were much different than TN.

About 8 days ago I planted potatoes in flower pots inside the house and 1 potato outside in a raised bed to try and keep that 1 potato dry it was 72 degrees that day. It rained 5 days, temperature was about 40 and the potato outside rotted already. The potatoes in the pots in the house are doing nothing. I was hoping to get a jump start by starting potatoes inside the house then transplant them outside but so far I'm not have much luck. I would like for the plants to be ready to dig by June 1st before temperature reaches 100 degrees. I bought Kennebec and Russet seed potatoes at the Amish Garden center. Now I am trying something new I have some potatoes in the sun no pots and some in the dark in pots all are inside the house in a sunny window it is 72 degrees in here but over cast no sun. I am hoping to learn what makes the potato eyes sprout and grow. A few years ago I tested the soil with a thermometer 3" deep it was 65 degrees, air temperature 76 and soil in direct sun light 95 degrees. I wonder if the 95 degree heat triggers the potatoes to grow. I learned beans and corn need to be 65 or above to grow. In high school science glass we put wet seeds in 70 degree and 90 degree incubator the 90 degree seed grew roots in 24 hours the 70 degree seeds too 3 days. It seems logical potatoes might like the warm sun too. This morning I checked the potatoes in the pots they all rotted. No more flower pot testing I will put all the potatoes in the window and hope the sun warmed them up and they grow sprouts at each eye. I would like to have an incubator there is a lot of cold air near the window, it is 40 degrees and over cast outside. This is not a very scientific experiment. LOL.

There are other things to consider. Even if I can make potatoes sprout inside the weather outside might be the wrong conditions, chances are very good all the potatoes will die when moved from inside the house to outside. Mother nature knows best. One way of the other I am going to learn something about potatoes.

[jal_ut]

" Mother nature knows best. One way of the other I am going to learn something about potatoes."

When do you plant sweet corn there? Here it works well to plant potatoes the same time as the sweet corn. Plant the sets directly in the garden. No transplanting. Here we look for certified seed potatoes. It is not seed, but tubers certified to be disease free. Also at times there are plugs available that have one eye on them and have been dipped in something. I would not plant spuds from the grocery store. Well, if they have sprouts starting to grow, yes they will grow, but you run the risk of propagating disease too.

[rainbowgardener]

Gary, where in TN are you? I am in very SouthEastern TN in the Chattanooga area. There's only a total of about a six weeks worth of days where it is above 90 in a year. We average exactly ONE day a year when it hits 100 degrees F. I would have thought being in the most South part of TN, it would be as hot here as anywhere in TN.