What Is True Potato Seed: Learn About Potato Seed Growing
If you have ever grown potatoes before, you are familiar with the process of planting seed potatoes. The term “seed potato” is actually a misnomer and a bit confusing when, in fact, it is actually a tuber and not a seed that is planted. This confusion leads one to ask, “Do potatoes produce seeds?” and, if so, why isn’t potato seed used for growing purposes?
Do Potatoes Produce Seeds?
Yes indeed, potatoes produce seeds. As with most plants, potato plants bloom, but usually the flowers dry and fall from the plant without setting fruit. You’re more likely to see potato seed growing on plants in regions where temperatures are on the cool side; these cool temps combined with long days promote fruiting in potato plants.
Additionally, some cultivars are more prone to fruiting than others. Yukon Gold potatoes are one example. This potato seed pod or berry is referred to as a “true potato seed.”
What is True Potato Seed?
So, what is true potato seed and why don’t we use it instead of tubers (seed potatoes) to propagate?
Potato plants produce small green fruits (berries) filled with hundreds of seeds and about the size of a cherry tomato and with much the same appearance. Although they resemble tomatoes and are in the same family as tomatoes, the nightshade family, this fruit is not the result of cross-pollination with tomatoes.
The fruit, although similar in appearance to a tomato, should never be eaten. It contains toxic solanine, which can cause headaches, diarrhea, cramps, and in some cases, coma and death.
True Potato Seed Information
While potatoes grown from tubers or seed potatoes produce an exact genetic clone of the mother plant, those grown from true potato seed are not clones and will have different characteristics than the parent plant. True potato seed is most often used by plant breeders to facilitate hybridization and fruit production.
Potatoes grown on commercial farms are hybrids selected for their disease resistance or high yields that can only be passed on through “seed potato.” This assures the grower that the desired qualities of the hybrid are passed down.
It is possible, however, to grow potatoes from true potato seed. It is wise to use heirloom potato varieties, as potato seed pods from hybrids will not produce good quality spuds.
To grow potatoes from true potato seed, you need to separate the seeds from the rest of the fruit. First, gently mash the berries, then place in water and let sit for three or four days. This mix will begin to ferment. The resulting floating fermentation should be poured off. Viable seeds will sink to the bottom and should then be rinsed well and allowed to dry on a paper towel.
Seeds can then be labeled and saved in a cool dry place until planting season. The seeds should be started indoors in the winter since plants started from seed take longer to develop than those started from tubers.
True Potato Seed Has Many Advantages
From: ECHO Development Notes (EDN) | EDN Issue #67
From: ECHO Development Notes (EDN) | EDN Issue #67
ECHO has just purchased two hybrid varieties of true potato seed (Solanum tuberosum) to share with our overseas network. This important subject requires some explanation though before discussing the details of these two varieties.
For centuries people have propagated potatoes by planting potato tubers, or pieces of tubers, that have “eyes” from which sprouts will originate. These are commonly called “seed potatoes.” This name can be confusing because they are obviously not seeds. I prefer the less confusing name, “seed tubers.”
Another important term is “certified seed potatoes.” As potatoes are grown and the tubers harvested, stored and replanted year after year, diseases build up in the tubers. The result is that the yield of potatoes decreases over time.
In order to get better yields, farmers can purchase potatoes that have been grown under extra-watchful (and I presume government-inspected) conditions and contain almost no disease. These are called “certified seed potatoes.” Unfortunately, in many countries certified seed potatoes are only available if someone imports them. They are heavy, bulky and perishable, so transportation costs to import potatoes and then deliver to the farmer are considerable.
But potatoes do produce seeds, so to help distinguish these from “seed potatoes” the seeds are called “true potato seeds” (TPS). Yet it takes only 160 grams of TPS to seed one hectare (2.3 ounces/acre) and half that amount if seeds are used for transplants. That compares with over 2,000 pounds/acre of seed tubers.
Another advantage is that TPS is always ready to be planted. I recall one summer when my father ran out of seed tubers in our garden. We went to the grocery store and bought some potatoes and planted them. Only after they failed to sprout did it occur to us that those potatoes might have just been harvested in a warmer part of our country and had not been dormant long enough to sprout.
There are now companies that grow true potato seed under equally careful conditions and produce seed that is even more disease and insect free than certified seed potatoes. So why not grow potatoes from true seeds like other vegetables?
Until recently the reason has been that TPS has great genetic variability. In other words, the genetic makeup of every potato grown from seed was unique. The Ontario Ministry of Agriculture and Food (Fact sheet 84-034, July 1984) states that in the 1800’s Luther Burbank planted TPS and carefully checked each plant. He selected one that was especially good that had a russet color. He named it the “Russet Burbank.” This continues to be one of the highest quality potatoes a century later (sometimes called Idaho baking potato in North America). In the early 1900’s competitions were held at some fall fairs in Canada for the best potato varieties produced by gardeners from TPS.
The International Potato Center (CIP) located in Peru specializes in potato research. (It is one of the international research centers in the CGIAR network–See ECHO’s book Amaranth to Zai Holes p. 39). One of their interests is TPS. Their small book True Potato Seed: Past and Present Uses by Malagamba and Monares (1998) provides a helpful perspective on use of TPS.
TPS has potential to extend the areas where potatoes can grown “where there is at least one season of approximately three months duration of climatic conditions favorable to potato cultivation.” (More on this later).
In warm regions there are three primary problems for potato growers. First, insects that transmit viruses from plant to plant present a much more serious problem than in major potato producing areas, which have milder climates. Virus buildup in the plants, transmitted in the seed tubers, quickly depresses production. Second, it is very difficult to store seed tubers in such warm climates.
A third problem is that “in many subsistence agriculture areas of the warm tropics, farmers do not grow potatoes because they do not have access to good [planting material] or have not found a way to store seed tubers under high temperatures.” Under such conditions, “direct transplanting of seedlings [from TPS] into the field appears to be a very suitable system.” “Once the seedlings have reached a desirable size, excellent growth and field performance are obtained by transplanting them either between the rows of a preceding crop–such as maize that is finishing its growth cycle–or in association with other crops of comparable growth habits. When storage conditions are favorable, part of the tubers produced from transplanted seedlings can also be utilized as planting material for the following season.”
In 1982 ECHO shared with our network the first TPS that was sold to gardeners in the USA. It was called ‘Explorer potato.’ The results were disappointing.
Explorer Potato, on the right, is small compared to a carefully controlled hybrid cross on the left. Photo from Ontario Ministry of Agriculture and Food.
The Ontario report cited above evaluated 'Explorer’ and found that there was considerable variability among plants in terms of type, size, skin color, shape of the tubers, size of the plant, days needed until maturity and cooking quality. In fact they required about 180 days to produce a crop. Tubers were about a quarter of the size that people expected. If these small tubers were stored till the next season and then planted, the harvest was then about normal. For those willing to put in this extra effort it was indeed a way to get a start at disease-free potatoes.
Until the hybrids we will tell you about came on the market, we recommended using TPS only as a start to disease-free seed tubers or as part of an effort to find a better potato for the region where you work. The latter can be done with minimal expense, as in the following account.
According to Hans Renia and Peter van Hest (“Botanical Potato Hybrid Seed is Ready for Market,” Seed World, January 1998, pp. 24,25) in the last decade there have been major advances in producing large quantities of hybrid seed and in the quality and uniformity of the product.
In 1995 the United States for the first time allowed importation of TPS. A company was formed that began to produce TPS in southern Chile where there are no major potato diseases. It is now owned by Bejo Seeds in the Netherlands. Now TPS are available at a reasonable price, in quantity, and have potential to compete with certified seed tubers.
In fact in 1997 in South Africa over 100 tons of harvested tubers from TPS plants were sold to the processor for the fast-food chain McDonalds, which has very high standards for their potatoes.
Aside from the question of seeds or seed tubers, is it even possible to produce potatoes in warm climates? Only in some situations. I called Peter van Hest with Bejo Seeds.
He said that potatoes will not produce tubers unless temperatures are less than approximately 70°F (21°C). Also they will not produce tubers if the difference between the day and night temperatures is less than 10 Fahrenheit degrees (5.6 centigrade degrees).
“Potatoes are also sensitive to day length. Potato varieties selected for temperate climates will set tubers during long days, [and probably during short days of the tropics too] but most tropical varieties will not begin to set tubers in northern latitudes until September when the day length is closer to 12 hours. In India we work with hybrids developed by CIP. In general a variety developed in and for the tropics might be better than one developed for higher latitudes. But CIP does not produce seed for sale, so it can be difficult to obtain enough for commercial use. Also CIP would be more concerned about general food use than quality and uniformity. ”
According to Dr. VanHest, “Our variety called 'Zolushka’ has shown wide adaptability in Indonesia and is an allpurpose potato suitable for many uses. The latest TPS varieties developed for the tropics by CIP might give a higher total yield (if you could find a commercial source), but ours would probably give a more commercially desirable product. Another good all-purpose variety is 'Catalina.’ It has proven versatile in the USA, South Africa, Egypt and Russia.”
Zolushka.’ Photo from Potato Products International, Ltd.
Is there any value to TPS in higher elevations of the tropics where potatoes are already a major crop? Chances are that diseases build up less quickly in such regions, but sooner or later either seed tubers or TPS will need to be used to maintain maximum yields. The factors of expense, transportation and storage already discussed may or may not favor TPS.
Because climate is likely to be more suited to storage than in warm climates, a few farmers might grow TPS through a couple seasons to produce seed tubers with minimal disease content–better than local potatoes used for replanting but still not “certified” seed tubers. Another option is to grow TPS plants at closer spacing and harvest large numbers of small tubers to be stored for planting the next season. In fact, very small tubers are now commercially available and can be less expensive to import than large seed tubers.
How to obtain seeds. ECHO has purchased seed for both 'Zolushka’ and 'Catalina.’ These are pelleted seeds, which means each tiny seed is enclosed in a material that makes it easier to handle. Those working with agricultural development programs in developing countries can obtain a free packet of each for trial. Others can order for $3.25 per packet plus $1 per order. The European Union does not permit importation of TPS, so European workers in the tropics should be sure to give your tropical address.
Two varieties are available. 'Zolushka’ has medium early maturity. It produces round-oval, medium to large tubers of uniform shape, shallow eyes, smooth white skin, cream/white flesh. Yield is good to very good. Broad range of adaptability over years and environments. Occasional growth cracks. Texture is fairly firm on boiling, little discoloration before or during cooking. Highly recommended for chips and fries.
‘Catalina.’ Photo from Potato Products International, Ltd.
'Catalina’ has medium/late maturity. It produces flat oval, fairly large, very uniform and attractive tubers with smooth white skin and shallow eyes, cream/white flesh. Fairly firm texture on boiling relatively free from discoloration before or during cooking. Occasional purplish spots in flesh in up to 3% of tubers if improperly grown (but these have no effect on health or taste).
What should I do if the potatoes do very well? We have been waiting to feature TPS until there were both good varieties AND commercial sources. (There is little point in doing a variety trial if you cannot purchase seeds nor save your own seeds). You can purchase additional packets from ECHO or purchase seeds in quantity from the Bejo seed company [not listed in 2015]. They also have subsidiary companies in India, Australia, Chile, Guatemala and Russia. Other varieties are available in some of these countries.
Meanwhile, if your trial does well and people like the potatoes, you can either consume the crop or save it to grow even more potatoes next year. Experience will soon tell you how many years you can save your own seed tubers before disease builds up and yields drop.
ECHO Staff 2000. True Potato Seed Has Many Advantages. ECHO Development Notes no. 67
The edible part of the potato plant is a tuber connected to the roots of the plant. While you can cut up the potato into plantable chunks and get more potatoes, the tubers themselves are not seeds, even though the ones you plant are called seed potatoes. The true seeds of the plant appear only rarely, in round, green seed pods. It shouldn't be surprising that these seed pods look like tomatoes because potatoes and tomatoes (Solanum lycopersicum) are members of the same plant family. Despite the similarity to tomatoes, these pods are not edible at all in fact, they’re poisonous due to the large amount of solanine they contain. Tomatoes, unlike annual potatoes, grow as perennials in U.S. Department of Agriculture plant hardiness zones 10 and 11, although they're usually treated as annuals.
The Absolute Beginner’s Guide to True Potato Seed (TPS)
There is a lot of information on this website about growing potatoes from true potato seed, but I often hear from people who are interested but who don’t have the time to read all of that material. If you have heard about TPS and are wondering if it is something that you would enjoy trying out in your garden, this should help you to make the decision.
If you have grown potatoes before, you probably started them from tubers. Somewhat confusingly, we call the tubers that you plant “seed potatoes.” The potato plant also makes actual seeds, which we call “true potato seeds” or just TPS. Seed potatoes are no different than the potatoes that you eat, with the exception that they are usually grown by specialist seed potato growers who pay particular attention to managing disease, since potato tubers can carry a lot more diseases than crops grown from true seeds. In contrast, true potato seeds come from the berries of the potato plant. The berries form when potato flowers are pollinated. Many people have never seen berries or even flowers on their potato plants, for reasons tied to climate and cultivar.
Why not just grow potatoes from true seed then? That’s the tricky part. Potato varieties are clones. When you plant a tuber of, say, Yukon Gold, you are really planting part of the same original plant that was first grown in the 1970s. Each generation of tubers is just more clones of that plant. Clones are predictable, which is a good thing for agriculture. True potato seeds, on the other hand, are the sexual progeny of the potato plant and, just like human children, each one is different. Every seed in every berry will produce a plant that is new and distinct from any other potato it is a brand new variety with newly jumbled up genetics. That potato is unique to your garden. When you grow potatoes from TPS, you are breeding new varieties. Even if you are only growing out seeds produced by someone else, you get to choose which varieties to keep and which to discard, based upon what matters most to you. You can keep them and replant the tubers indefinitely. You can name them, share them, or even sell them if they are particularly good.
Seed Potatoes vs. True Potato Seeds
|Seed Potatoes||True Potato Seeds|
|Tubers are genetic clones of the parent plant||Seeds are genetically unique progeny|
|Results are predictable and uniform||Results are unpredictable and diverse|
|Tubers can be planted directly in the soil||Seeds are started indoors, similar to tomato|
|Tubers can carry a lot of diseases||Seeds carry few diseases|
|Tubers last about a year||Seeds can last 50 years in the freezer|
|Selection is limited, with less than 100 varieties available commercially||Selection is very wide, with access to many unusual types|
When you grow potatoes from true seeds, you will usually get a wide range of results. Some plants may produce nothing, while others can produce a tremendous yield. Most will be somewhere in the middle. Depending on what seeds you start with, you may get unusual colors and shapes that you would never find at the grocery store. Most of the seed potatoes that are available to gardeners are the same varieties that are used in large scale agriculture. They tend to be optimized for best production in potato growing regions and they have traits that best suit growers and processors, rather than consumers. If you live in potato country and you are totally happy with grocery store spuds, TPS might not be for you. You aren’t likely to get better varieties with commercial traits than the ones that already exist. On the other hand, if you are trying to grow potatoes in an area where the commercial varieties don’t do very well or you find grocery store spuds a little dull, TPS is probably just what you are looking for. Just have a look at the kinds of results that we get from our true potato seed mixes:
There is incredible depth to the potato. If you are looking for something that you can grow in your garden that will never show you the same thing twice, you would probably enjoy TPS. If you have only been exposed to grocery store potatoes, you have barely scratched the surface. TPS gives you access to a whole new dimension of flavors, colors, and textures available in Andean potatoes and there are also nearly 100 species of wild potatoes, many of which can be crossed with domesticated potatoes to introduce new traits. The process of growing potatoes from true seeds can seem intimidating, but if you can grow tomatoes from seed, you can grow potatoes from seed. There are some common mistakes to avoid when growing TPS, but once you get past those, growing potatoes from seed is easy. If you find it interesting, you can also get very deep into the technical details of potato breeding and learn more than you ever imagined. You could probably spend a lifetime exploring potatoes from TPS and never get bored. I could, anyway.
The easiest way to get started growing potatoes from TPS is to start from seeds. If you are in a favorable climate, you might be able to save seeds from potatoes that you already grow, but this is a bit tricky for most people. The plants that you grow from TPS are much more likely to form berries than plants grown from commercially available seed tubers. Once you get started, you can easily save your own seeds and keep growing.
Start your seeds in flats or pots no more than eight weeks before your last frost. For most people, it would probably be best to start them four weeks before the last frost to keep from planting them out too early. Grow them under lights. Ambient light is not enough for potato seedlings. Keep the temperature between 50 and 70 degrees. Too hot or too cold and they will be slow to emerge. When the seedlings are about six inches tall, harden them off and then transplant outdoors, burying them up to the top set of leaves. You can make starting TPS more complicated than that, but for your first attempt, it should work just fine.
You can buy many kinds of true potato seeds in our store. For absolute beginners, I recommend the Wide Tetraploid True Potato Seed Mix. If you are ambitious, there is a lot more available at our true potato seed page.
Our Potato Growing Guide covers planting, growing, and harvesting one of our favorite vegetables! Also, see tips on how to store potatoes to keep them fresh—and some homemade potato recipes.
Potatoes can be planted very early in the gardening season—as you soon as the frost is out of the soil and you are able to work the soil!
Folklore offers many “best days” for planting potatoes:
- Old-timers in New England planted their potato crops when they saw dandelions blooming in the open fields.
- The Pennsylvania Dutch considered St. Gertrude’s Day (March 17, aka St. Patrick’s Day) to be their official potato-planting day.
- Many Christians believed that Good Friday was the best day to plant potatoes because the devil holds no power over them at this time.
See more information about planting potatoes below.
Planting Dates for POTATOES
When to Plant Potatoes
Potatoes prefer cool weather.
In Northern regions, some gardeners will plant the first crop of early-maturing potatoes in early to mid-April, 6 to 8 weeks before the average last frost date or as soon as the soil can be worked they can survive some cool weather but the threat of frost is a gamble. If there is a threat of frost at night, temporarily cover any sprouted foliage with mulch or an artificial covering such as old sheets or plastic containers (and be sure to remember to remove the coverings in the morning).
- To avoid frost, consider starting potatoes 0 to 2 weeks after your last spring frost. You may plant earlier, as soon as soil can be worked, but be aware that some crops may be ruined by a frost or overly wet soil.
- The soil, not the calendar, will tell you when it’s time to plant. The temperature of the soil should—ideally—be at least 50°F (10°C). The soil should also not be so wet that it sticks together and is hard to work. Let it dry out a bit first. Like other seeds, potato seed pieces will rot if planted in ground that’s too wet.
In Southern regions, potatoes can be grown as a winter crop and planting times range from September to February. Where winters are relatively mild, you can plant a fall crop in September. In central Florida, gardeners plant potatoes in January and in Georgia they plant in February.
Preparing the Planting Site
- Potatoes grow best in cool, well-drained, loose soil that is about 45° to 55°F (7° to 13°C).
- Choose a location that gets full sun—at least 6 hours of sunlight each day.
- Grow potatoes in rows spaced about 3 feet apart.
- With a hoe or round-point shovel, dig a trench about 6 inches wide and 8 inches deep, tapering the bottom to about 3 inches wide.
- Spread and mix in fully-rotted manure or organic compost in the bottom of the trench before planting. (Learn more about soil amendments and preparing soil for planting.)
Preparing seed potatoes for planting. Photo by tanyss/Getty Images.
How to Plant Potatoes
- In each trench, place a seed potato piece (cut side down) every 12 to 14 inches and cover with 3 to 4 inches of soil.
- If your garden soil is very rocky, put the seed potato pieces directly on the ground. Sprinkle with a mix of soil and compost. Cover them with straw or leaves, hilling the material up as the potatoes grow.
- The best starters are seed potatoes. Do not confuse seed potatoes with potato seeds or grocery produce! Select seed potatoes which have protruding eyes (buds).
- Use a clean, sharp paring knife to cut large potatoes into pieces that are roughly the size of a golf ball, making sure that there are at least 2 eyes on each piece. (Potatoes that are smaller than a hen’s egg should be planted whole.)
- If you are cutting up potato pieces yourself, do so 1 to 2 days ahead of planting. This will give them the chance to “heal” and form a protective layer over the cut surface, improving both moisture retention and rot resistance.
- 12 to 16 days after planting, when sprouts appear, use a hoe to gently fill in the trench with another 3 to 4 inches of soil, leaving a few inches of the plants exposed. Repeat in several weeks, leaving the soil mounded up 4 to 5 inches above ground level (this is called “hilling” and is explained more here.).
- After the potato plants have emerged, add organic mulch between the rows to conserve moisture, help with weed control, and cool the soil.
Check out this excellent video to see how to plant potatoes.
How to Grow Potatoes
A critical part of growing potatoes is to not let their tubers (i.e., the potato crop) be exposed to sunlight for too long. Exposed tubers will turn green and produce a toxic compound called solanine, which makes them bitter, inedible, and potentially nausea-inducing.
To combat this, we employ a technique called hilling.
Hilling is simple: As a potato plant grows, it produces a main stem with leaves and flowers aboveground. Meanwhile, underground, tubers form on secondary stems that branch off from the main stem. In order to prevent shallow tubers from being exposed to sunlight and to encourage the plant to keep producing more tubers, a few inches of soil are periodically “hilled” up around the base of the stem. This is typically done three to four times during the season.
Tips for growing and hilling potatoes:
- Do the hilling in the morning, when plants are at their tallest. During the heat of the day, plants start drooping.
- Maintain even moisture, especially from the time when sprouts appear until several weeks after they blossom. The plants need 1 to 2 inches of water per week. If you water too much right after planting and not enough as the potatoes begin to form, the tubers can become misshapen.
- The last hilling should be done before the potato plants bloom, when the aboveground part of the plant is at least a foot tall. Hoe the dirt up around the base of the plant in order to cover the tubers as well as to support the plant.
- Practice yearly crop rotation with potatoes.
- Potato Scab: Most likely caused by a high soil pH. Remember: Potatoes like acidic soil (do not plant in soil with a pH higher than 5.2). Dust seed potatoes with sulfur before planting. Some readers suggest adding pine straw on top of the potatoes when planting for natural anti-bacterial elements.
- Colorado potato beetles need to be hand-picked and predatory birds will often eat them. While they’re in the nymph state, they can be controlled with diatomaceous earth (food grade) which is a non-toxic way to control pests in the garden. If they continue to be a problem, a few sprays of Spinosad, an organic pesticide, will get rid of the beetles. Always use products at dawn or dusk to avoid harming beneficial insects.
- Flea Beetles
- Early/Late Blight
When to Harvest Potatoes
- Regular potatoes are ready to harvest when the foliage begins to die back. (See each variety for days to maturity.) The tops of the plants need to have completely died before you begin harvesting.
- “New potatoes,” which are potatoes that are purposefully harvested early for their smaller size and tender skin, will be ready for harvest 2 to 3 weeks after the plants stop flowering. New potatoes should not be cured and should be eaten within a few days of harvest, as they will not keep for much longer than that.
- Toughen up potatoes for storage before harvest by not watering them much after mid-August.
- Dig up a test hill to see how mature the potatoes are. The skins of mature potatoes are thick and firmly attached to the flesh. If the skins are thin and rub off easily, your potatoes are still too new and should be left in the ground for a few more days.
- Potatoes can tolerate light frost, but when the first hard frost is expected, it’s time to get out the shovels and start digging potatoes.
How to Harvest Potatoes
- Cut the brown foliage off and leave the potatoes for 10 to 14 more days before you harvest. This allows the potatoes to develop a thick enough skin. Don’t wait too long, though, or the potatoes may rot (especially in moisture-laden soil).
- Dig potatoes up on a dry day. Dig up gently, being careful not to damage the tubers. Avoid cutting or bruising potato skin. Damaged potatoes will rot during storage and should be used as soon as possible. The soil should not be compact, so digging should be easy.
- If the soil is very wet, let the potatoes air-dry as much as possible before putting them in bags or baskets.
- Don’t leave the potatoes that you have dug in the sun for long after they have been dug up from your garden, otherwise your potatoes may turn green. Green potatoes have a bitter taste due to the presence of solanine, and if enough is eaten, can cause vomiting and diarrhea. Small spots can be trimmed off, but if there is significant greening, throw the potato out.
- Allow freshly dug potatoes to sit in a dry, cool, dark place (45 to 60°F / 7 to 15°C) for up to two weeks. This allows their skins to cure, which will help them keep for longer.
- After curing, make sure you brush off any soil clinging to the potatoes.
- Whether you dig your own potatoes or buy them at a store, don’t wash them until right before you use them. Washing potatoes shortens their storage life.
- After curing, do not put potatoes near apples the apples’ ethylene gas will cause potatoes to spoil and go bad.
If you’re buying potatoes to eat within a few days, storage is not an issue. You can store anywhere.
For long-term storage, potatoes need the following conditions: ventilation, cool temperatures, high humidity, and no light. Storing potatoes in your home isn’t easy unless you have a root cellar. Most home temperatures are kept at 65 to 75 degrees F and potatoes need be stored at cool temperatures to avoid sprouting.
Recommendation for Home Storage
- Store at cool temperatures (42 to 55 degrees F). Warm temperatures encourage sprouting and disease. Storage options include: an extra refrigerator set a few days higher than normal an unheated entrance, spare room, closet, attic, cabinet, basement, or garage insulated to protect potatoes from freezing.
- The room must have high humidity. Potatoes are 80% water so it’s too dry, potatoes wither and dry out. Options are a damp cellar OR you can elevate humidity by storing tubers in plastic bags that are perforated (with many holes cut in the side) to provide fresh air OR / AND placing large pans of water in front of air source.
- Avoid all light to prevent greening. The location must be dark or use dark-colored, perforated plastic bags with many holes cut in the side to allow for air movement.
- Potatoes need ventilization. Even after harvest, potatoes still use oxygen and give of carbon dioxide so they must have fresh air. Never put potatoes in airtight containers Use perfermated bags as mentioned in steps above.
The fruit (metaphorically speaking) of a very happy potato plant!
There are more than 100 varieties of potatoes! In the home garden, most people grow tan-skinned or red-skinned potatoes with white flesh.
To chose a potato to grow, think about how you like to eat them.
- Russets and long white potatoes are used to make baked, boiled, or fried potatoes.
- Round white potatoes are used for either boiled potatoes or potato chips.
- Red-skinned potatoes are often used for boiling or for potato salads.
There are also speciality potatoes in many shapes, sizes, and colors, including all-blue potatoes as well as potatoes with red or yellow flesh. We also love All Blue Potatoes! They’re delicious and, well, they’re truly blue!
- ‘Irish Cobbler’: tan skin, irregular shape (great heirloom potato for delicious mashed potatoes!)
- ‘Norland’: red skin, resistant to potato scab
- ‘Mountain Rose’: red skin and pink flesh, resistant to some viruses
- ‘Red Pontiac’: red skin, deep eyes (easiest and most adaptable red potato there is to grow)
- ‘Viking’: red skin, very productive
- ‘Chieftan’: red skin, resistant to potato scab, stores well
- ‘Katahdin’: tan skin, resistant to some viruses
- ‘Kennebec’: tan skin, resistant to some viruses and late blight
- ‘Elba’: tan skin, large round tubers, resistant to blight and potato scab
See our page on how to choose the best potatoes to grow in your garden for more information on recommended varieties.
Wit & Wisdom
- Before planning your garden, take a look at our plant companions chart to see which veggies are most compatible with potatoes.
- Did you know: Potato promoter Antoine Parmentier convinced Marie Antoinette to wear potato blossoms in her hair.
- Grated potatoes are said to soothe sunburnt skin.
“What I say is that if a man really likes potatoes, he must be a pretty decent sort of fellow.”
– A. A. Milne, English writer (1882–1956)
True Potato Seed Information - Do Potatoes Produce Seeds - garden
Posted by Organic Heirloom Gardens on Feb 7th 2018
The seed potato debate is older than any of us…. cut or whole? Big or small? Some are very passionate about their opinions on this subject. You will find people on either side of the issue have their reasons for this method or that. You even have companies out there (we won’t name any names) making claims that WHOLE seed potatoes when planted will produce 20% more than pre-cut…….Is this true. Well it can be in a way but the statement is a bit misleading. First off the word "more" is subjective to the reader's interpretation. It could mean more weight, it could mean more quantity of potatoes in number. Heck the way it reads it could mean MORE of anything you wish, like Star Trek garden gnomes or flying pandacorns. )
Any good politician would be applauding right now. To say that “THE ONLY REASON a seed potato would produce more weight or quantity of tubers is because it is whole” is absolutely FALSE. There are many factors that play into total yield in weight, quantity, and size of potatoes. The least of which is if the potato seed is cut or whole.
So let's get to the truth as it pertains to home gardens and break this down in a way everyone can understand without reading hundreds of pages worth of research papers. We will try to stay out of the weeds (so to speak) because the data is actually rather extensive believe it or not. Which of course begs the question what some claims made about seed potatoes are based on. Especially claims from companies that are supposed to be able to provide an informed recommendation to their customers.
Keep In Mind: This is for home and small gardens. Most studies were conducted for large operations. They are geared towards using every ounce possible for planting and using an automatic potato slicer for being uniform all around in order to make the most possible profit and least possible loss. Think of it like you making a burger and McDonald’s making a burger. If you make a ¼ pound hamburger and it actually ends up weighing ½ pound then you don't eat it all you just wasted meat and money yes, but not much. If McDonald’s messes up their weight by even ½ ounce on every burger for one day, they just wasted literally TONS of meat and money. That is why these studies are so precise and overplay factors that really just are not life changing for the home gardener.
Cut Or Whole Seed Potatoes?
- Pros - less chance of disease, more stems emerge, more food for emerging plants
- Cons - slower to emerge, too many stems in one area can cause crowding, eyes not pointing up
- Pros - more potatoes to plant, plants emerge quicker, eyes pointing up
- Cons - more disease prone if not healed properly
An in depth study on Russet potatoes states:
“Cut seed produced a higher yield of tubers > 51 mm diameter in comparison to all whole tuber seed sizes, with the exception of the 28 and 56 g sizes. In terms of total yield, the 28 and 42-g whole seed tubers yielded significantly less than all other seed sizes examined”.
Whole & cut seed will both produce potatoes to harvest though varying in size and yield.
What we are seeing is that the cut seed was producing a higher yield of LARGE tubers over 51mm at harvest in comparison to ANY sized whole seed potatoes in the study except 2 sizes.
In terms of total yield weight, cut seed produces just as much as whole seed on average.
As a matter of fact, two sizes of the whole seed produced “significantly less” in total yielded weight than any other seed in the study. There goes the 20% more from WHOLE potatoes huh? BUT WHY? There has to be more at play here than “cut or whole” affecting yield.
Note: Always allow cut seed potatoes to “heal” or “scab over” before planting. After cutting let them sit out for several days until they dry some on the outside and form a new “skin”. The leathery dry surface that forms helps protect the cut seed from disease.
Potato Eyes & Stems
Now when it comes to eyes and stems per plant there is a question to be asked…….
Do I want BIG POTATOES or small potatoes?
A study at the University of Idaho College of Agriculture states:
“For Russet Burbank, an average of 2.5 to 3.5 stems per plant is considered optimum for maximum performance in commercial plantings. The number of eyes per seed piece influences stem numbers per plant.”
If you want BIG POTATOES for baking, etc. then you want your whole potato or cut piece to have 2-4 eyes facing towards the sky. If you already have stems sprouting from the eyes you want to get 2-4 stems per piece or per plant. This is going to give each stem plenty of room to produce large potatoes.
If you want small potatoes you want more eyes per whole potato or cut piece of seed. This of course will produce more stems. You want 5-8 stems per plant, all facing towards the sky. This is going to produce more potatoes per plant but they will all be smaller.
Size/Weight Of Potato Seed
Nora Olsen, Ph.D., extension potato specialist at the University of Idaho Kimberly Research and Extension Center and president of the Potato Association of America tells rodalesorganiclife.com:
“We do not recommend planting a seed piece or whole tuber smaller than 1.5 ounces,” “If you plant a whole seed or seed piece below this size, the resulting plant may not be as vigorous and large as desired and may yield fewer and smaller tubers.”
This basically tells you all you need to know. The seed (whether whole or cut) needs to be over 1.5 ounces. Many times it is stated between 1.5-3 ounces, but it can be over 3 ounces as long as it has the number of stems you are looking for.
Again as a home gardener you do have to realize that much of the data in the studies you will find goes into things we are not as concerned about. None of the papers were geared towards anyone planting under a few hundred acres. SURE, we want to be efficient and buy less seed to plant more land! However it does get a bit tedious. If you were planting 1000 acres it would matter if you were cutting all of your seed pieces to between 1.5 and 3 ounces but guess what? I bet you are not planting 1000 acres. A 5 ounce piece with the correct number of stems will do just as well or better than a 3 ounce. You use more seed material is the only downside.
So. Seed always over 1.5 oz., between 1.5-3 oz. best, but over 3 oz. still works…….Got it!
Potato Row & Plant Spacing
Planting For Larger Potatoes But Less Quantity
- Row Spacing @ 36 inches
- Plant Spacing @ 11-14 inches
Planting For Smaller Potatoes But More Quantity
- Row Spacing @ 27 inches
- Plant Spacing @ 7-9 inches
- Don’t always trust what you hear or read until you examine the data.
- Understanding who the study is made for will help you to understand the data better.
- A seed potato can be various sizes.
- You can plant whole or cut seed potatoes with equal success.
- Larger seed potatoes can be cut into pieces to make several smaller seed potatoes.
- The number of stems per seed helps determine size of potatoes that grow.
- The weight of a seed (whole or cut) should always be over 1.5 ounces.
- 1.5+ Ounces with 2-4 stems per seed, plant space 11-14”, row space 36” for BIG POTATOES.
- 1.5+ Ounces with 5-8+ stems per seed, plant space 7-9”, row space 27” for small potatoes.
It is possible to grow potatoes from seed, and plant breeders do this to create new varieties. Using potato seeds instead of seed potatoes is akin to fruit tree growers using fruit seeds to grow trees instead of grafting scions onto rootstock. Seed potatoes give you potatoes that have the desirable qualities of specific varieties, while potato seeds give you potential new varieties that you could play around with, hand-pollinating plants that you wanted to try breeding. Growing potatoes from seeds can be difficult, and the University of Illinois Extension even calls it “a troublesome and unrewarding exercise.”
Suzanne S. Wiley is an editor and writer in Southern California. She has been editing since 1989 and began writing in 2009. Wiley received her master's degree from the University of Texas and her work appears on various websites.