Years ago, I was looking for some “definitive” information on how to grow potatoes. I consulted an old copy of Organic Gardening Magazine. In it, they had done a side by side comparison of a bunch of different potato growing techniques, including putting them in a bin and continually adding material as the potatoes grew. (You know the memes on this, where you open the bin at the end, and a gazillion potatoes fall out). Turned out, the highest yields came from simply planting the potatoes in the ground, so that’s what I’ve always done.

Side note, because someone is likely to mention it. I’m familiar with the Ruth Stout method of growing potatoes, mentioned way back in the 1960’s in her 1963 book, Gardening Without Work. You simply put the potatoes down on a bed of really deep mulch (minimum 8″) and then cover the potatoes with more mulch. When you harvest, you simply pull the mulch back from the potatoes. No digging required. It’s essentially a “no dig” method of growing potatoes.

I did learn early that too much “hot” fertilizer can cause scab on the outside of the potatoes. Scab is harmless but unsightly, and if you are the kind of person who likes to eat potato skins, like I do, you’d like to avoid it. I stopped fertilizing with freshly composted chicken manure, and most of my scab issued disappeared.

And I’ve been plodding along growing potatoes for the last 20 years or so, somewhat successfully. Never quite getting them hilled up enough to prevent a few green skinned ones. Never quite nailing how to fertilize these hungry relatively deep rooted plants without over doing it. Never quite getting the watering regime quite right (I never cut off the water soon enough and end up harvesting muddy potatoes). They say an average yield is 10 fold what you have planted. So for every 1 lb of potatoes you put into the ground, you should get about 10 lbs back. I GUESS I’m in that range?

I’ve battled gophers and the occasional potato beetle, struggled with the occasional late frost that set the plants way back or grown a huge tuber only to discover “hollow heart”, which is a bit of discoloration and a hollow cavity in the center of the tuber that forms from overly rapid growth. I’ve failed to “hill” my potatoes and ended up with WAY TOO MANY green ones. I’ve stored my potatoes in the wrong place outside while “curing them” and ended up with WAY TOO MANY green ones.

I’ve always resisted the idea of cutting up potatoes and letting them scar over before planting them, as it seemed like an opportunity for disease and rot to enter. So the tuber I got was the tuber I planted, regardless of size. And I’ve more often than not planted some of the left over potatoes from the previous year (cause let’s face it, seed potatoes are EXPENSIVE)! Usually some of the WAY TOO MANY green ones, even though all the books told me that this was the WORST thing to do because of cumulative disease build up in the tubers. I’ve never SEEN disease issues from this, so I’ve just kept doing it.

Mostly, I’ve struggled with storage. My beautiful potato crop comes in, often as early as late August, and then by January, I have sprouts in my pantry that are sometimes over a foot long. I don’t have optimum storage facilities on my homestead. My potatoes end up living in my garage pantry, which is insulated, but subject to varying temperature fluctuations depending on the outside weather. I have zero control over humidity.

The blue varieties I’ve grown seem to be the worst culprits for breaking dormancy early, followed closely by the red varieties, and then the yellow and russets. Pouring through potato growing information and seed catalogues, which never seems to be well organized, I’ve struggled to understand which varieties have the longest dormancy in not ideal storage conditions, and resigned myself to pressure canning or freezing potatoes in January so that I don’t lose the rest of the crop.

I’ve always felt like something was missing in my knowledge of growing potatoes.

Last November, I attended the annual Washington Tilth Alliance Conference, and sat in on an inspiring presentation by Brendon Rockey of Rockey Farms out of Center Colorado. Because of a previous job, I knew exactly where Brendon’s operation was located, and as part of the San Luis Valley, the unique climate it represented. Rockey Farms specializes in seed potatoes.

A recent two part series by the YouTube channel Lazy Dog Farm, in which he interviewed Jim Gerritsen from Wood Prairie Organic Farm in Maine, further increased my potato growing knowledge. Wood Prairie grows organic seed potatoes for mail order sale. They specialize in potatoes with great taste that do well under organic production conditions.

I feel like I FINALLY have a better handle on how to grow potatoes well.

Information I’ve Been Missing

What is the relationship between days to maturity and storage length. Should I simply avoid any potatoes that are considered early (70-90 days) or mid (90-110 days) season if I want my potatoes to store into early spring?

  • Yes! The later maturing varieties generally hold their dormancy longer than the early varieties (though dormancy is controlled by a whole host of factors, many of which are weather related and out of the growers hands). So plant early and mid season potatoes for fresh eating and the late maturing ones for longer term storage.

What really is the optimum planting depth and spacing of my potatoes?

  • Planting depth: 1 to 4 inches deep (more shallow for colder climates, more deep for southern parts of the US). I’ve been planting my potatoes WAY too deep.
  • Plant spacing: 10-12 inches apart, except for fingerlings, which, weirdly, should be 14-18 inches apart. I’ve been planting my potatoes too far apart.

What is the optimum planting time for potatoes in my area?

  • When your soil, 4″ down, reaches 50 degrees in the early morning, before the sun warms it up. I find the easiest way to predict soil temperature if you don’t have a thermometer is to use this soil temperature map for your zip code (this site is a GAME CHANGER). For our area, soils reach the 50 degree range in early to mid April. I prefer to plant later because there’s less chance of a hard frost killing off the above ground growth later in the month.

Do determinate vs indeterminate varieties really matter? (I only just learned that potatoes come in determinate and indeterminate types a few years ago, and it seems impossible to find a definitive list of which varieties are which).

  • In short, no. Most commercial varieties are determinate (they do all of their growing at once and then die back, rather than continue to put on potatoes throughout the growing season. The key here is that POTATOES ARE A COOL SEASON CROP! When daytime temperatures are over 90 degrees, the plants tend to die regardless of whether they are determinate or indeterminate. So for our area, with its trending hotter longer summers, there’s no point in seeking out indeterminate varieties. I’m also considering throwing a shade cloth over the row as our temperatures start to raise.

What’s with disease issues? Does it really matter if I don’t buy certified seed potatoes every year?

  • Potatoes are wildly susceptible to various viruses, spread from plant to plant by insects with piercing sucking mouth parts; most frequently by aphids. As these viruses collect and proliferate in the potato plant, they slowly decrease the yield of the actual potato. Because these viruses accumulate in the potato tuber itself, which is essentially a clone of its parent, planting previous year’s potatoes means you are accumulating more and more virus over time. You may never actually SEE any signs that your potatoes are infected with viruses. You will simply see smaller and smaller potatoes as the years go by. These viruses are harmless to humans.
  • Evidently, before tissue culture of seed potatoes became common, some varieties experienced “running out”, where the propagation of the variety did not yield viable sized potatoes due to accumulated viral loads.
  • Here’s a bit of a behind the scenes look at how commercial seed potatoes are grown. Seed potatoes are propagated vegetatively rather than from actual seed (you CAN grow potatoes from true seed, but that’s a whole other blog post). The tubers we harvest actually grow out of the plant’s stem, rather than from the roots. Along the stem there are lateral growth points, or buds. Each of these buds has a meristem (a small populations of rapidly proliferating cells that can produce all the adult organs of a flowering plant). Meristems have no vascular system and therefore are less prone to viral, fungal and bacterial infections. These meristems are grown as a tissue culture in a lab until they form small “plantlets”. This tissue is tested repeatedly for disease infection to ensure they are disease free. They are sometimes called pre-nuclear.
  • These plantlets (think the size of an alfalfa sprout) are then grown out in greenhouse conditions, where disease spreading insects can be excluded, to grow “mini” tubers. These plants are sometimes referred to as nuclear, and are the most disease free seed tubers you can buy. These mini tubers are then grown out in open field conditions to produce the first generation of “seed” potatoes. Most states limit the number of generations these potatoes can be grown out and sold because each subsequent generation will have more virus accumulation. Higher elevation and colder climate sites have less insect pressure and therefore often have a slower disease build up.
  • When you buy seed potatoes, you are normally buying “certified” seed potatoes. While the criteria for this certification differs from state to state, it does ensure that the potatoes you are receiving meet certain criteria for variety, size, are free from various diseases and mechanical damage (though not necessarily viral diseases), and that the specific generation of grow out is included in the information on the box. See HERE for USDA details. Washington Dept. of Ag Certification Program HERE.

Wouldn’t it make sense that the larger the starting tuber, the more potatoes you’d get?

  • Yes, you do get more yield when you plant a larger potato, but you also have to buy more seed potatoes to plant the same size patch, as larger potatoes don’t go as far, so its a trade off.

Do I really need to cut up my seeds into individual “eyes”?

  • Each “eye” on a potato grows a stem, and that stem creates a whole new plant. Studies have shown that the ideal size “seed” potato is from 1 1/2 to 2 3/4 oz. (About the size of a large chicken egg). So cutting up your larger tubers into approximately 1 1/2 to 2 oz squarish pieces, each with at least one eye, and spreading them out when planting will give you the highest possible yield for the lowest pounds planted. 1 lb of potatoes should plant 8-10 feet.

What is Chitting or Greensprouting and should I do it?

  • Greensprouting is the process of waking the potato up from dormancy. To greensprout a potato, warm up the seed potatoes to room temperatures, while keeping the plant in the dark, for 7-10 days. Once sprouts emerge from the eye, expose tubers to light and drop temperatures to 50-55 to slow growth. This process has been shown to cut 10-14 days off of your time to stem emergence once planted. Once the stem has emerged, the plant has a tremendous ability to fight off rot. So greensprouting is definitely a win/win for both disease protection and time to harvest.

When is the optimum time to harvest my potatoes?

  • You may have heard that if you see blooms on your plants, there are potatoes forming underneath. This is a critical time for growth of your potatoes and adequate moisture is extra important! You can, of course, reach around under the plant and pick a few ping pong sized potatoes here and there once you see your plants blooming, but they won’t reach optimum size until the plants have died back on their own. This can range from 70 to 130 days depending on the particular variety. So for me, if I plant April 15th, harvest can range from late June to late August. Pay attention to those maturity estimates!
  • Even that last week between starting to look sad and fully dead can see a decent increase in tuber size, as the tuber pulls back the energy from the plant into itself. Most importantly, the more fully mature the potatoes are when you harvest them, the longer they will keep in storage! So don’t feel like a bad gardener if you don’t get your potatoes dug right away (if you can keep the gophers from eating them all before you get them out of the ground!)
  • Some varieties simply hold dormancy longer than others, due to a whole host of genetic and environmental factors. A few reportedly long storing varieties include:
    • All Blue
    • Baltic Rose
    • Burbank Russet
    • Butte Russet
    • Elba
    • German Butterball
    • Katahdin
    • Kennebec
    • Prairie Blush
    • Red Chieftain
    • Red Cloud
    • Red Pontiac
    • Rose Finn Apple Fingerling
    • Russian Banana Fingerling
    • Sapro Mira
    • Yukon Gem
    • Yukon Gold
  • Your mileage may vary. I have not found All Blue, Red Chieftain or Red Pontiac to do particularly well under my storage conditions.

What IS the ideal way to store potatoes for home use to keep them from sprouting?

  • You’ve probably anways heard to NOT refrigerate your potatoes. This is because under refrigerated conditions, some of the starches can turn to sugars, and that increased sugar can cause an unwanted darkening of the potato when its deep fried. I personally wouldn’t care about a color change and rarely deep fry potatoes anyway. This increased sugar does not affect coloration when potatoes are boiled or roasted.
  • According to the University of California Davis, 40 degrees F with high humidity and good airflow is the ideal storage condition for fresh eating. Conditions that don’t generally exist on the homestead. I’m starting to think the best answer is to store potatoes in an extra refrigerator in my garage.

My issue is that I don’t have access to large amounts of straw/mulch for inexpensive prices (I plant up to a 100 ft row of potatoes, so I’d need a LOT of mulch, and I’d need to reapply several times during the growing season to prevent green potatoes). The one time I did use straw as a mulch, I germinated about a gazillion weed and grass seeds that became a nightmare to pull out. I love the idea, and if I had a giant pile of mulch to utilize, I’d absolutely give this more of a go. But it does require deep soil fertility to be successful. Potatoes have surprisingly deep roots and are heavy feeders. If the mulch you are planting in isn’t already well composted, your potatoes are gonna be hungry and your yield small.

So there you have it. A much deeper dive into the ins and outs of growing potatoes for long term homestead use. I’ll be doing a better job of selecting my potatoes for an early and then a late harvest this year, and I’ll bite the bullet and go ahead and order seed potatoes through the mail. I’ll likely order from Fedco (they carry close to 50 varieties). I’m looking at Yukon Gem or Caribe for an early variety, perhaps Kauka Gold, Elba and Katahdin for late varieties. I also like Pinto as a fingerling.

© Miles Away Farm 2023, where we’re Miles Away from perfecting our potato growing techniques, but are willing to keep experimenting. Want more content? Sign up for a monthly newsletter to your email inbox HERE