Category: Garden

 

Can you grow potatoes in your garden by planting grocery-store potatoes?  If you search the internet, you’ll find every possible answer to this simple question.

The correct answer is: It depends.  But not in some wish-washy, random, some-do, some-don’t, luck-of-the-draw kind of way.

It depends on whether or not those grocery-store potatoes were treated with the sprout inhibitor chlorpropham.  That substance keeps potatoes from sprouting by permanently damaging their ability to grow.  And it is commonly used in the U.S., for potatoes sold at the grocery store.

Key fact:  Potatoes labeled as “organic” cannot legally be treated with chlorpropham.

So, if you want to buy potatoes from the grocery store and plant them, buy potatoes labeled as organic.  In five years of doing that, I’ve never had that fail.

By contrast, planting non-organic potatoes from the grocery store may or may  not work.  It depends on whether or not they were sprayed with chlorpropham before being shipped off to the grocery store.  And there’s no way to tell, just by looking at them.

Separately, there’s more to this issue, because, unlike “seed potatoes”, grocery-store potatoes are not certified as “virus free”.  But I think that’s more of an issue for commercial growers than it is for the casual home gardener.

Details follow.

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The damnable thing about reality is that it keeps changing.  Just when you think you have some tiny part of it figured out, somebody upsets the apple cart potato bin.

I’m not talking about the pseudo-culture-wars  around the rebranding of the Potatoheads.

And I’m not referring to the consequences of the Federal Web Designer Full Employment Act.  This is the 1997 Federal statute requiring that every commercial and governmental website must make significant changes in layout and functionality, any time more than half of its users have figured out how to use it.

Nope, today’s rant is about spuds at Home Depot.  Bags of certified seed potatoes, for spring planting, prominently displayed for sale.  These were offered with several other items I’d never seen there before, including onion sets and, of all things, pomegranate seedlings.  (Apparently, hardy to USDA Zone 7 as figs are — with the occasional die-back in a hard winter.)

I don’t recall ever having seen seed potatoes at my local Home Depot, and I’m not quite sure what that implies.

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Why are those potatoes there, now?

I know why I grow potatoes.  I tried it in 2020, and I liked the results.  I grow a modest amount of potatoes because:

1. 1. They’re easy to grow.
   2. Deer won’t eat them (so far).
   3. They taste better than store-bought.
   4. You get a lot of edible calories per square foot of garden.
   5. They store well.

I figured that almost nobody in my area (northern Virginia) grew potatoes in their back yard.  For one thing, our heavy clay soil is far from ideal.  If you decide to get around that issue by going the “no-dig” route, your home-grown potatoes will end up costing more than store-bought (see Post #1073).

And it’s not as if the potato is some beautiful addition to the garden landscape.  It’s a scruffy green plant with nondescript flowers.  Not only are you supposed to clip the flowers off, you have to spend weeks looking at the dying foliage before you can dig up the crop.

And so, as of last year, this tiny part of my world made sense.  Potatoes are cheap to purchase, expensive to grow in our ill-suited soil, and not much to look at in any case.  And I couldn’t find seed potatoes locally.  It was all completely reasonable.

You don’t see snowmobile dealerships in Florida.  You don’t see masses of seed potatoes for sale in a Home Depot in the Virginia suburbs of Washington DC.

But now, my local Home Depot is offering several different varieties of pre-chitted seed potatoes. 

Those don’t appear anywhere on their website.  The only way to know that my local store has them it is to walk into the store and — surprise — they have enough bags of seed potatoes for hundreds of local gardeners to be growing potatoes this year.  What I’m saying is, it’s not like they decided to test the waters with a few packages tucked away on a shelf somewhere.  They have cardboard bins full of 1-pound bags of seed potatoes.

And they aren’t even cutesy, exotic spuds, the kind you’d market to the upscale gardeners in this area.  Home Depot is offering your basic red, white, and gold potatoes, just as you’d buy in the grocery store.

And so my world view is turned upside down.  Is this some new fad that has somehow passed me by?  Has there been some viral potato-based meme?  Is Yukon Gold the new black?  Has some post-pandemic survivalist instinct kicked in?  Or has there always been some quiet, underground population of potato fans in this area, and has Home Depot has finally decided to crack the lucrative home-potato market?

Change is bad.  Inexplicable change is worse.  What’s the take-home message when Home Depot is offering the seed stock for what amounts to cheap survival food, front-and-center in a mid-aisle display?

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Can you grow potatoes bought at the grocery store?  Answer:  Buy organic potatoes.

Please note, I’m not saying “should you”.  I’m answering the more basic question “can you”.  Internet advice is all over the map.  Some people swear it doesn’t work at all.  Some people swear it works fine.

The real answer is, it boils down to the type of sprout-inhibiting treatment that was applied to those potatoes.  And, as far as I can tell, the treatment that permanently prevents the potato from growing is not legal for use in potatoes  labeled as “organic”.

So, yeah, in theory, you can use organic grocery store potatoes, with a pretty good chance they’ll grow just fine.  You still risk importing potato viruses into your garden if you grow grocery-store potatoes.  But advice that you literally can’t grow potatoes from grocery-store potatoes does not apply to to the sprout-inhibiting treatments legal for use on organic potatoes.

Detail follows.

If you grow potatoes, in theory, you’re supposed to use “seed potatoes”.  The first time I tried potatoes, that’s what I did.  I bought some on-line from a seemingly reputable dealer.  It was an expensive failure.  None of my super-duper seed potatoes sprouted.  Given the cost (and the cost of shipping), I’m sure I’d have bought them locally if I could have found them.

Ever since that first flop, I’ve gone against standard advice, and simply bought eating potatoes locally and planted them. 

That’s risky because you might introduce some long-lived potato diseases into your garden soil that way.  For this reason, potatoes sold as seed potatoes must be certified as being more-or-less virus free, and commercial potato producers in most (possibly all) areas are required to plant nothing but certified seed potatoes (or something close to that, or deemed equivalent to that).

There is some internet chatter suggesting that it’s illegal for a home gardener to plant store-bought potatoes in (e.g.) Idaho.  But if you actually read the statute, that doesn’t appear to be the case.  In Idaho, it’s illegal to sell potatoes for planting that are not certified as disease-free seed potatoes.  (For what it’s worth, that’s also what the law of the Commonwealth of Virginia says.  And, I’d wager, that’s what the laws in every state say (e.g., Florida).)  But in addition, in it’s illegal for commercial growers in Idaho to plant anything that is more than one generation removed from certified seed potatoes.  But nothing in Idaho statute (or at least, that part of the statute) addresses home gardens.

But if you’re just a casual potato grower, probably the bigger risk is that your grocery-store potatoes may not grow.  By the time you get to late winter/early spring, it’s a good bet that almost all eating potatoes you can buy from almost any source have been treated with some type of sprout inhibitor or “anti-spudding agent”.  (Because, if not, given how they have to be stored so that they remain pleasingly edible, they’ll have started to sprout by that time, if not treated.)

In the U.S., commercial, non-organic food potatoes are most commonly treated with chlorpropham (reference).  This is basically a powerful herbicide, and there’s enough concern over toxicity that the EU and Great Britain banned its use starting in 2019 (reference).  It works by permanently damaging the ability of potato cells to reproduce.  Even contamination with low levels of it greatly impacts subsequent growth of the potato plant (reference).  And I noted that the concentration of Chlorpropham used in that last study was well below the 30 PPM limit on residues on food potatoes for sale in the U.S (reference, U. Idaho extension service.)

If you read about someone trying and failing to grow potatoes or getting a terrible yield, using food potatoes, or you’ve seen advice not to use store-bought potatoes, you’re probably reading about the effects of chlorpropham.  If that’s been applied, there’s no way to reverse the effects.  It fundamentally and permanently alters the ability of that potato to grow.  (And, see above, it even stunts any successive generations of crops grown from those potatoes, if you can get them to grow in the first place).

Now we come to the $100 question:  Can chlorpropham (CIPC) legally be used on U.S. potatoes marketed as organic potatoes?  This University of Idaho publication pretty clearly says no, it cannot:

Alternatives to CIPC are needed for both organic and export markets—where CIPC is not permitted.

(But if you really want to be sure, you have to consult the USDA National List.  If it’s a synthetic compound, and it’s not on the list, it’s not allowable for use in produce labeled organic.  And, to be clear, it’s not on the list.  So, not allowable for use in production of potatoes labeled as organic.)

Organic methods of potato sprout inhibition have turned to using substances that are Generally Recognized as Safe (GRAS), or that are themselves natural compounds, or that are on the USDA National List.  The sprouting of potatoes stored under normal conditions can be inhibited with ethylene gas, or by application of concentrate essential oils such as clove or mint oil, or by use of hydrogen peroxide (reference, reference).  You can also keep sprouting down by judicious choice of potato variety, or choice of varieties that can be stored at colder temperatures without loss of flavor/conversion of starches to sugars.

Here’s the key point:  Most organic methods of sprout suppression do not permanently damage the potato.  They will kill off the sprouts that are active.  Some temporarily inhibit new sprouting.  But they don’t prevent further sprouting, once they are stopped.  In fact, one of the main drawbacks of these organic methods is that they have to be re-applied if the potatoes remain in storage.  Here’s the key paragraph, from the University of Idaho publication cited above, emphasis mine:

These alternative compounds are not true “sprout inhibitors” that inhibit sprouting by interfering with cell division or some other biological process. Volatile oils and hydrogen peroxide are more correctly called sprout suppressants, as they physically damage developing sprouts with a
high concentration of the product in the surrounding headspace in the potato storage. Because of high volatility, these compounds leave behind little or no residue. Since new sprouts continue to develop, repeat applications are required at two to three week intervals or on a continuous basis.

Source:  Organic and Alternative Methods for Potato Sprout Control in Storage, by Mary Jo Frazier, Nora Olsen, and Gale Kleinkopf, University of Idaho, September 2004.

Courtesy of the same University of Idaho group, you can see what a potato treated with clove oil looks like.  The clove oil kills off the existing baby sprouts, leaving little black dead sprouts all over the potato.  But this will not prevent the potato from re-sprouting.

Source:  Potato Sprout Suppression from Clove Oil, By Nora Olsen, Mary Jo Frazier and Gale Kleinkopf

Based on the many, many bags of grocery store potatoes I looked at this spring, that picture looks awfully familiar.  I’m not sure whether you truly can tell whether a potato has or has not been treated with a commercial essential-oil sprout suppressant.  But I’ve noticed a lot of these little black dead sprouts on the organic potatoes at the supermarket.  And I’m guessing that what I’m seeing is potatoes that have been treated with these sprout suppressants, and not chlorpropham.

For my first-ever crop of potatoes, I got mine at my nearest farmers’ market, after my boxes of seed potatoes failed to grow.  That worked great.  Since then, I tend to cruise the bags of organic potatoes at by local grocery stores, looking for ones that are showing the very first signs of sprouting.  My experience is that if you can see those tiny little white (not black) sprouts forming, they’ll grow OK.  They are already in the process of recovering from whatever organic sprout suppression treatment was applied.  And getting them at the grocery store is both cheap and convenient.

In any case, potatoes are a crop where you have to get started early.  By the time I saw I could buy seed potatoes at Home Depot, it was too late for this year.  You’re supposed to “chit” the potatoes before you plant them, that is, get them to break dormancy and start sprouting.  That chitting process takes a month or two.  If you want to plant your spuds on the traditional date of Saint Patrick’s day, you have to buy them and set them to chit sometime around the end of January.  So I already had a couple of trays of sprouting potatoes in my kitchen by the time I saw the commercially-available product at the Home Depot.

Finally, I repeat, you can grow them this way.  Whether the casual gardener should do that is an open question.  This does not address the issue of potential spread of viruses harmful to the potato.  I’m not sure how common those are in food potatoes, but for sure, they are common enough that every state that I’ve looked at has standards that seed potatoes must meet.  Further, if you introduce a particularly harmful virus into your garden soil, my understanding is that it effectively ruins the soil for potato production for years.

And, when you get right down to it, it’s not like there’s a huge cost savings, once you get your local big-box stores selling seed potatoes.  Home Depot has certified seed potatoes $4 a pound.  If the only trusted alternative is organic potatoes at the supermarket, you’re probably going to pay $2 a pound anyway.  Had I known that Home Depot was going to be marketing these this year, I’m not so sure I’d have been buying and chitting organic grocery store spuds.

But, for now, it is what it is.  I had one complete flop using certified seed potatoes, and excellent success (so far) using farmers’ market and organic grocery store potatoes.  For now, I continue to grow mine from food potatoes.  I’m not sure that it’s smart, but so far, it works.  And that may change, now that my local big box has them ready-to-plant, right off the shelf.

Anyway, if you go the grocery store route, pick up a few bags, to spread your risks.  Leave them out to chit.  I figure, if they start putting out sprouts sitting in my kitchen, they’ll probably do just fine when I plant them in the garden.  If they don’t, eat them.

This will be the last time-lapse of peppers ripening.  Who would have guessed that this just wouldn’t be very entertaining.

Part 1:

Part 2:

 

Yes, sort of.  Slowly.  Here’s five days of ripening of a bowl of green cayenne peppers.

Tune in next week for the thrilling finale.

 

 

This is the gardening post I started to write yesterday.  We’ve finally hit full fall conditions here in Northern Virginia, with frost or near-frost conditions each night.  So this is a post about a few final things I learned in this year’s gardening.

In a nutshell:

• If you are planting sweet potatoes, plant lots of slips, rather than counting on the spreading of the vines to fill your beds.
• Radiant barrier works well to extend the fall season of low-to-the-ground crops such as lettuce.
• Might as well plant what survives well, rather than struggle to keep ill-suited crops alive.

Sweet potato nuances:  In times of famine …

“In times of famine, we’d be glad to have that.”  That’s the polite phrase my wife uses when I pull some undesirable bit of produce out of the garden.

It’s far nicer than “who in their right mind would eat that”, yet makes the same point.  It can be said equally of the undesirable (e.g., eggplant), the ludicrously undersized (e.g., pinky-sized carrots), and the only-partially-edible (e.g., spade-marked potatoes).

But before I diss the sweet potato as mere famine-food, let me sing its praises.  As far as I can tell, it needs absolutely no care whatsoever, other than keeping it watered until it gets established.  It grows like a weed, covering its beds and shading out any actual weeds.  It puts out lovely little morning-glory-type flowers (as it is in the same family as morning glory).  It produces a lot of calories per square foot.  You can plant it beneath taller plants (such as sunflowers or peppers) and it’ll cover the ground beneath and produce tubers.  And harvest is easy — peel back the vines, scrape the soil, and you’ll see the tops of the sweet potatoes, ready to be pulled.

The yield of calories per square foot is only slightly lower than potatoes (per this reference).  If I’ve done the metric-to-ridiculous conversion correctly, that works out to just about 100 edible calories per square foot for either of them.

I learned one important thing about sweet potato cultivation this year:  Plant lots of slips.

This year, I grew them on a lark.  I had a few store-bought sweet potatoes that had gotten moldy, and I decided to try to grow slips from them rather than just toss them.  One out of three moldy potatoes yielded slips. But I figured it wouldn’t matter, as they would spread, and could be easily propagated by cutting the ends of vines and re-planting them.

So I started with just a handful of slips, and I let those spread to fill out the allotted portions of the beds.  I had heard that the vines would put out sweet potatoes wherever they set down roots, as they spread out.  I figured that I’d end up with a bed full of sweet potatoes, despite starting with just a few plants.

That was a mistake.  Sure, the vines will put out additional sweet potatoes as they spread.  But each vine only puts out big sweet potatoes at the original rooting spot for that vine.  As it went along, it produced additional sweet potatoes at various nodes along the vine.  But all of those “secondary” sweet potatoes were much smaller.  

Here’s my harvest, from about 50 square feet of raised beds.  (The hammer is  there to give a sense of scale.)

By weight, I ended up with a roughly 60/40 mix of sweet potatoes of the size you’d see in the store, and sweet potatoes of the “in times of famine” variety.  Large enough that they’re probably worth the effort of peeling and eating.  But only just.

The moral of the story?  In my climate (Zone 7), plant lots of slips.  You can grow them the lazy way, by planting a few slips and letting the vines run to cover the allotted bed space.  But you don’t want to.  That gives you a few good-sized sweet potatoes, and a whole lot of undersized ones.  I’d have done far better to have had three times as many slips, and kept the vines one-third as long.

Would I plant these again?  You bet.  I’m just going to plant them a little smarter next year.  Stick them in the ground in the spring.  Come back in the fall and harvest a significant amount of food.  That’s pretty hard to argue with.

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Radiant barrier for late lettuce.

In April (Post #G21-018), I tested the idea of using a radiant barrier to keep raised beds warm at night.  And by tested, I mean tested.  I used data loggers to track temperatures overnight in beds with and without a radiant barrier cover.  The cover raised the bed temperatures by about 10F.

In Virginia, 10F should add about a month to the growing season.  In Vienna, VA, over the past 30 years, the median date at which nighttime temperatures reached 22F or lower was roughly December 8.  Compared to an expected first-frost date in the first week of November.

So, this fall, I’m putting that to use.  Beneath the radiant barrier above is a small patch of lettuce.  So far, practice validates theory.  My lettuce is still alive despite a couple of frosts so far this week.  I hope to grow that lettuce — albeit slowly (Post #G21-055) — into December.

In the end, I’m not sure this is any less effort than a hoop-house style greenhouse, set atop the bed.  (PVC pipes bent into semi-circles, anchored to the ground, and covered with clear plastic sheet.)  But I already own the pieces of radiant barrier, cut to size.  So radiant barrier it is.  It works.

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Final harvest before winter:  Peppers and other stragglers.

With frost coming, I did that garden ritual of picking absolutely everything that was left in the garden.  That yielded the artfully arranged jumble you see above.  Or the more orderly view of the same pile, below.

This year, overwhelmingly, what was left was peppers.  Green to the left, banana to the right, cayenne at the top.  (The cayennes are green, but in theory they will turn red now that they’ve been picked.)

I’m ambivalent about peppers.  They don’t produce a lot of calories.  But they pickle well, they’re OK in salads, and they have the outstanding advantage of taking care of themselves.  Nothing around here seems to bother them much.

The lesson learned here is that I didn’t start out to have a pepper-heavy garden.  With the exception of the eggplant and beans, these are the long-term survivors of what I planted back in the spring/early summer.  With the lesson being that if I’m aiming for the best yield per unit of effort, maybe I need to change my attitude toward a family of produce that manages to last the whole year with no effort on my part.

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Concluding remarks for the 2021 gardening year.

At the end of 2021, the only things left growing are some lettuce, and some garlic that I planted for harvest next year.  So now’s a good time to recap and tentatively plan for what I’ll grow next year.

Non-food crops:  Sunflowers, marigolds, zinnias.  These are nice for taking up the odd corners of the garden and attracting bees.  Zero upkeep other than watering the sunflowers in the driest part of the year.  The sunflowers require serious deer deterrents.  But they look nice, they feed the bird and the bees.  So why not grow them again.

Low-maintenance starchy root crops:  Potatoes, sweet potatoes.  Those are both a definite yes for next year.  So far those have been zero maintenance with good yield.  Fresh potatoes tasted particularly good.  I won’t bother with fingerling potatoes (turned out way too small).  I’ll plan to fill a bed with sweet potato slips, rather than count on the spread of the vines to fill the bed.

Tomatoes:  Yes, but.  I will continue to “follow the rules” as I did this year, including staking and trimming.  But I need to stagger the plantings by month so that I have them coming in all year.  I have a least-effort process for making small batches of tomato sauce down cold (Post #G21-046).  But if I’m going to end up making sauce, I should just go ahead and plant Romas or similar, as that should be much more energy-efficient (Post #G21-046).  The home-dried tomatoes were a big hit, so I will definitely do that again next year.  Given that, it’s well worth working out a practical way to do that with solar energy, in my humid climate (Post #G21-050).

Cucumbers and summer squash.  I’m going to give those a pass next year.  I expected these to be mainstays of my garden.  Instead, after one year of bliss, they turned out to be nothing but trouble.  I how have a garden area infested with cucumber beetles and targeted by squash vine borers.  I may consider growing parthenocarpic (self-fertile, no-bees-needed) cucumbers under netting.  But honestly, once you reach that point, it’s like Mother Nature is telling you to grow something else.

Butternut squash.  Those are a definite yes.  They seem to grow well, produce a reasonable yield of calories per square foot, and keep well once harvested.  And they’re tasty.  I can even keep the powdery mildew off them if I’m willing to put in the effort (Post #G20).  The traditional Waltham variety has beaten all others that I’ve tried.  And they all taste the same.  So I see no reason to plant anything but that.

Green beans.  Despite early failures, those are definitely on the list.  For some reason, my first two plantings got hit by common bean mosaic.  Only the last planting had a significant yield.  They are labor-intensive to pick, but when they grow, they produce a nice steady yield.

Peas.  Of course, peas.  No work, some yield.  Every year, I am tempted into growing “bush type” peas, figuring they need no support.  Every year, I regret that when I end up with a tangle of peas that is difficult to harvest and impossible to weed.  So my pledge is never to grow peas without support again.  No matter what.

Beets, rutabagas, turnips, radishes.  Maybe.  I’m taking radishes off the list.  Even if they grow to size, I just don’t like them enough to bother to grow them.  Beets have been a total failure due to failure-to-sprout.  But I now know this is a common problem in heavy soils, and I’ll try something new next year.  Rutabagas and turnips were a near-total-failure this year, for reasons unknown.  But the turnip varieties that grew were tasty — not at all like the turnips of my youth.  So these remain on the list, if only because, in theory, you can get an early spring crop of them.  I’m not going to bother with a fall crop because, unlike the spring crop, the fall-planted ones were devastated by insect or insects unknown.

Lettuce:  Yes.  I never had any luck at all in the past, but this year, the lettuce seemed to thrive with no intervention on my part.  Zero calories, but nice in salads.  I’ll go for both a spring and a fall crop again.

Peppers.  Well, I guess so.  I mean, they are edible, they produce a nice steady crop, and (this year, at least) they seem to grow with no intervention on my part.  They make a nice lacto-fermented pickle when there are more than can be eaten at once.  Now that I know that I can grow them, rather than pick up the first seed pack I see at the hardware store, I’ll do a little more research on sweet pepper varieties.

Others.  I’ll probably try okra again, but only if I can get my hands on some of the high-yield varieties.  Four mature Clemson Spineless never gave me enough pods at one time to do anything with.  Eggplant, I may try for a late-spring planting.  A planting for fall harvest yielded a lot of leaves and little in the way of anything edible.  I have a few herbs that may overwinter, and I have garlic started for harvest next year.  I may try walking onions next year.  Not that I’m particularly fond of them, but every other variety of onion I have tried has failed.  I’m still undecided on pumpkins, if only because they need a lot of space and a lot of time to mature.  If I plant them again, they are going in early, in the back corners of the yard.  And then if they survive, great, and if they don’t, so be it.

That’s it for this garden year.  I don’t anticipate posting anything about gardening until next year.  If then.

 

Source:  Weather Underground, 10-day forecast for Vienna, VA accessed 10/19/2021.

This is the first year that I specifically planted vegetables in late summer, for fall harvest.

I didn’t adequately anticipate how slowly vegetables grow as we move into fall, here in Zone 7.  I’m still growing vegetables, but I’m certainly not growing a lot of vegetables.

Given that growth appears to have slowed to a crawl in my garden, I’d like to have some guess as to just how slow a crawl that is. Continue reading Post #G21-055: The slow fall garden