Posts about gardening and related topics, such as canning and maybe other aspects of food preservation.
Do I have sufficient statistical power to test the effect of potato chitting, in my back-yard garden? Or is it laughable to think I might be able to learn anything whatsoever about the effect of chitting, from a single small-scale potato planting?
The upshot is in red below. Chitting has to make quite a bit of difference, in order for it to show up in this small sample. Continue reading Post G24-002, Addendum: Chitstistix, a power test.
Above you see the start of some ginger and turmeric plants. These are just a few ounces of off-the-shelf organic ginger and turmeric roots, from the grocery store, cut/broken into pieces, soaked for a bit, pressed into some damp potting mix, covered with more potting mix, then left on a 20-watt seed starting heat mat to sprout.
I ought to start seeing green sprouts emerge in a week or two.
I admit, these were an impulse item. I was at the grocery store, getting some potatoes (for chitting) and sweet potatoes (to get going, for slips for planting), and I noticed the ginger root. I’ve heard that it can be grown in my area (hardiness zone 7). So I picked some up. And if I’m doing ginger, I might as well do turmeric, as they are close relatives and have similar growing requirements.
My advice: Before you start these plants, start with a little math. My growing season is maybe 6 months long. (The Old Farmer’s Almanac lists my growing season as 186 days (reference). Most sources say that ginger requires a 10-month growing season. So, one way or the other, absent a greenhouse, these are going to be houseplants for about four months. One way or the other. Before I can plant them out in the garden.
I haven’t quite worked out how I’m going to manage that. But rumor has it that these will sprout in their own good time, so it’ll be a matter of some weeks before I’ll need to start dealing with that. If they sprout at all.
I mean, how hard can it be, right? Plus, all that delicious turmeric ale.
Finishing off my root/tuber/rhizome starts are my sweet potatoes.
I have sung the praises of the lowly sweet potato elsewhere (Post G23-065). It’s food that can look after itself. Once you get them started, you prune them to keep them from taking over. And dig up some food at the end of the season.
The only hard part is coaxing a handful of sweet potatoes to sprout, so that you can plant the sprouts. And even that isn’t hard, it just seems to take forever. Plop a few sweet potatoes into a box full of potting soil, keep it warm and moist, and wait. And wait. And wait.
So I start my sweet potatoes now — around Groundhog Day. Which seems ridiculous, given that they really don’t want to go out into the garden before May 1 or so, at the earliest. But it really does seem to take them months, every year, to begin producing slips. So in they go.
Aside from remembering to water them every once in a while, this is zero effort. You just have to remember to do it early enough, every year.
This post is a classic example of why nobody consults this blog for gardening advice.
If you are a back-yard gardener, and are considering whether or not to grow potatoes, you want advice. Directions. You want somebody to say do this, do that. Follow this approach and success is guaranteed.
But much internet-based advice for the home gardener is folklore. Frequently repeated, never tested. Certainly not tested by the folks who repeat it. Such folklore is sometimes helpful, sometimes merely harmless, and sometimes dead wrong.
What I’m supposed to say in this post is something like “it’s time to chit potatoes now, before you plant them”. That is, get them to break dormancy and sprout first, then plant the sprouted potatoes. And then I’m supposed to explain how I go about doing that.
As if I were somehow privy to the innermost secrets of potato-chitting.
What I’m actually going to tell you is this:
This year, I’m going to set up a little experiment to test the impact that chitting has, for my potatoes, here in Northern Virginia Zone 7.
But in this post, I’ll first explain how I go about growing potatoes in my back-yard garden. I ignore almost all the rules on proper potato etiquette. So it’s not clear what my advice is worth, anyway. But unlike your average garden blogger, I’m up-front about that.
Free advice is worth what you pay for it.
Even though potatoes are cheap, I grow them for a lot of reasons, but mostly because it’s easy and effective.
Deer won’t eat them. Neither, so far, will the bugs. In a good year, they produce a lot of calories per square foot. Within reason, you can harvest them whenever you’re ready. They keep well. They taste better than grocery-store potatoes. And around here, they’re done by mid-summer, and you can double-crop with beans or some other short-season crop. Last year, I planted late-season corn after my potatoes were done.
I start by buying organic potatoes from the grocery store. Organic, to avoid buying potatoes sprayed with a potent sprouting inhibitor (Post G22-004). From the grocery store, because I’m cheap, and it’s convenient, and so far, it works just fine.
There are some downsides to this. You have no clue what your varieties are. This year, mine are “red” and “gold”, per the picture above. If you live in the South, don’t bother with russets, as they take too long to mature for this climate (Post #G23-035). Other than knowing to avoid those, you have no idea if your grocery-store potatoes are early-season, mid-season, or main-season potatoes. (In the South, you would like to avoid long-season (main-season) potatoes, because potatoes don’t like Southern summer heat.) If you get a particularly good or bad crop, you can’t replicate the variety. And so on. Not to mention, no guarantee they are virus-free.
OTOH, given that I can typically get potatoes at the grocery store for around 80 cents a pound, as the price of seed potatoes, with shipping, approaches $10/pound, if you do this “right”, you have to have a pretty good yield, just to get your money back. It’s just a lot less stress to pick up a bag or two at the grocery store, than to obsess over which variety of ludicrously expensive seed potatoes to order.
I chit them near a window, at room temperature, starting on or about Groundhog Day. Just set them out, on a tray, and watch for sprouts to start. It’s less than totally decorative, but it’s close to no effort. This in USDA Zone 7, so adjust accordingly for your climate. This is roughly 10 weeks before the expected spring last frost date in this area.
See last section for discussion of chitting.
I plant on St. Patrick’s day, after cutting them into chunks the day before. St. Patrick’s, because I can remember the date. And because that’s about four weeks before our expected last frost date in the spring. Planted in the cold of March 17, it takes about a month for the shoots to emerge from the ground, so that, ideally, you’ll see those potato shoots just after danger of frost has passed.
Dig a little trench 4″ or so deep, chuck in the potatoes, cover them up, toss a little mulch on top. I aim for about a 1′ to 1.5′ spacing in all directions. Conventional wisdom says that if you plant them further apart, you’ll get fewer, larger potatoes. Makes sense, but I can’t say that I’ve tested that. You’re also supposed to “hill” them after they have grown a bit — just mound up a little more dirt onto the potato stems. Apparently the entire point of hilling is merely to keep the sun off the potatotes, so they do not form poisonous solanine (see Post G23-065, on why green potatoes can kill you, but green tomatoes won’t). Anything sufficiently opaque — dirt or mulch — will do.
That long time lag between planting and sprouting is a good reason to chit. If, somehow, your seed potatoes aren’t going to sprout, if you don’t chit, you’ll only find out about it a month or so after you planted them. Eventually — call it six weeks later — it will dawn on you that you aren’t seeing any potato sprouts, and you need to re-plant. Which, in the South, means you’ll end up trying to finish off your potatoes in the heat of summer, which is a bad idea.
I plant them in dirt. I’ve tried no-dig potatoes using straw (worked great, but straw bales are too expensive in my area, Post #1073), and no-dig potatoes using leaf mulch (dismal failure, but hey, the leaf mulch is free in my area, Post G23-041). Separately, for a variety of reasons, I’m not going to grow potatoes in containers. So dirt it is.
Why mess around with no-dig potatoes? Clay soil. Potatoes don’t like the heavy clay soils in my area, so it takes a huge amount of soil amendments (or bringing in topsoil, which I did for my raised beds) to get dirt that potatoes will grow well in. If you have clay soil, and want to try potatoes, do-dig is a lot less effort. In addition, you can use a year of no-dig to convert some lawn to garden bed, if you bury it deeply enough in mulch. Either way, in the right circumstances, no-dig is a way to reduce the total effort involved. (Also, the potatoes come out nice and clean.)
Why did no-dig potatoes in leaf mulch fail miserably, but no-dig potatoes in clean straw were a success? In hindsight, I think that it allowed the potato tubers to get too hot. I have since seen one excellent gardener (Self-Sufficient Me, on YouTube have a near-identical potato failure using no-dig in leaf mulch. Upon reflection, I think that the dark, compacted leaf mulch, in full sun, allows the potato tubers to get too hot, leading to few potatoes set, small potatoes, and knobby potatoes. Potatoes really do not like heat. If I do no-digs again, I’ll keep the soil temperature in mind, and either use deep, light-colored mulch, or set up a shade cloth over them.
Separately, regarding fertilizing potatoes, I dump enough leaves on the garden each year that I don’t have to worry about adequate soil nutrients such as nitrogen. But potatoes, in particular, are supposed to benefit from adequate potassium in the soil. It’s good for their skins. (And, correspondingly, potatoes in the skin are a high-potassium food.) It’s easy enough to test your soil for potassium with one of those $10 soil test kits from the hardware store, and if lacking, to spread minute amounts of potassium chemical fertilizers before you plant a potato bed.
Weed and water them, just like any other plant in the garden.
I pull off the flowers as they form. This, because the internet tells me to do so. This process aligns the potato plant’s chakras or something. I have no clue whether it makes any difference or not. Just FYI, potatoes have pretty white flowers.
I harvest them when the tops die back. Or I want the garden space for something else. Once they start laying lying down and looking straggly, that’s a good sign that they are done for the year, and can be dug up at my convenience.
Note, however, that potatoes do not like heat. In a warm-summer climate like Virginia, those tops are going to die back sometime around mid-July, no matter whether the tubers underground are finished or not. If I could pick my varieties, I’d grow early-season (short-season) potatoes. But given that I grow mine from grocery-store potatoes, … whatever happens, happens.
If I’m lucky, I’ll come in at the low end of the yields posted above. Not sure if it’s the climate, the soil, the gardener, or the lack of care. Just be aware that a lot of the miracle yield claims you’ll see on the internet are complete, total, and intentionally misleading bullshit. When in doubt, check with your local extension service to see what you can reasonably expect in your area.
Why chit? Conventional wisdom says this will lengthen your growing season by perhaps a week or two (reference, University of Utah). I.e., put you a week or two head of the game, compared to planting without chitting. In the South, that’s a good thing, as potatoes don’t like heat, and they are going to die off in the heat of mid-summer, ready or not. Plausibly, you’ll get an extra week of growth before the heat kills off your potatoes, and that should translate into higher yield.
But, as with so much advice for the home gardener, everybody repeats this, and seemingly nobody tests it. There’s surprisingly little hard evidence on the benefits of chitting potatoes, and what evidence there is is mixed (per the Guardian newspaper).
If you search the internet, you’ll see disagreement on almost every aspect of chitting. The only thing I’m sure of is that it’s optional, because commercial growers don’t chit them. But seemingly experienced gardeners disagree on:
As a one-time professional user of vague, observational data, to me, this signals that the benefits of chitting, if any, are probably modest. If chitting had some huge benefit, people would have noticed.
In fact, I’d say there’s a case to be made that “chitting” was invented as a way to control the inevitable sprouting of potatoes in some climates, absent climate-controlled spaces. You’d bring your potatoes out of the root cellar, into the light, to green up the sprouts and control the rate of sprouting, so that they’d still be viable when planting time finally came around.
So this year, I’m going do to a little experiment. I’m taking half of each bag of potatoes, pictured above, and chitting them. And leaving the other half in the fridge for the next six weeks. This, now done, via the classic one-potato, two-potato randomization.
I then weighed the two randomly-assigned samples, and used a coin flip to determine which was to be chitted, and which was to be stored cold for the next six weeks.
I’ll be planting the chitted and un-chitted spuds, in more-or-less similar plots, on St. Patrick’s day this year. I’ll track their progress and, absent catastrophe, will weigh the final yield sometime mid-summer.
I realize there’s a lot of potential for random variation in this, despite my best effort to draw from the same batch of potatoes, randomize, and then plant as nearly identically as possible. I nevertheless think this can be informative. If, at the end of the season, I can barely tell the difference between the chitted and unchitted spuds, then I think that’s a pretty good clue that chitting has a relatively modest impact on yields. At least, in my climate, my garden, with my spuds, this year.
So, the null hypothesis is that chitting makes no difference. I’ll see if I can plausibly reject that. Expect results sometime around the 4th of July.
Wait, haven’t you already read this post? Continue reading Post G24-001: It’s Groundhog Day. Again.
This is a quick followup to post #1921, where I dumped some winter pond maintenance bacteria into one side of my tumbling composter, to see what would happen. The question was whether or not that would keep my composter working in the cold of winter.
Now, one month later, the short answer is, not. There is no detectable difference in the level of (un-decomposed) compost, between the treated and un-treated sides.
The upshot is that the only way I’m going to be able to keep that composter working throughout the winter is to heat it. A little passive-solar-heated shed didn’t do the trick. These cold-loving bacteria didn’t do the trick. And having an electrically-heated outdoor composter is a total non-starter, for me.
At this point, I give up. I just won’t compost kitchen scraps over the winter.
You might reasonably think that a post featuring my rotting kitchen scraps is a new low for this blog …
… though I’d bet there are some in the Town of Vienna who might disagree. But that’s water over the dam.
In any case, you’d be wrong, because today I treated half that pile of rotting kitchen scraps with cold-water pond … eh … stuff. That converts this pile of rotting (or, more precisely, non-rotting) garbage from a mere oddball gardening obsession into an exciting citizen-scientist experiment.
Anyway, as promised in Post #1917, I leveled up the two compartments in my tumbling composter and added cold-water pond treatment to one side. This stuff:
The idea being that a big dose of psychrophilic (cold-loving) bacteria might jump-start my kitchen-scrap composting.
Composting activity has pretty much ground to a halt, due to the cold outdoor temperatures, despite my having built a little insulated solar shed for the tumbling composter.
Methods: After leveling up the two sides of the composter, I added about a third of the bottle to one side of the composter, in several small doses, tumbling the compost vigorously with each dose. And added a packet of something advertised as enzymes to break down cellulose (though that seems more than a bit far-fetched to me, for reasons I won’t go into). I’ll tumble it daily, maybe add another treatment in two weeks or so.
In a month, I’ll check to see whether or not the level of compost in the left (treatment) side has dropped materially below the level in the right (control) side.
This is my last-ditch effort to get my tumbling composter to continue working through the winter. This pond treatment cost $30, so I figure I ought to try to get my money’s worth. If the stuff doesn’t work for this use, at least I can affirmatively document that it doesn’t. Hence running this as a controlled experiment, instead of just dousing the whole batch of compost at once.
I’ll be surprised if it works. But that’s what experiments are for.
Results in a month.
Source: Maps are from USDA. I added the line marking the boundary between hardiness zones 5 and 6.
… and nobody cared.
Which is a good thing. I think. On balance.
On the one hand, it’s good that they released it. That’s my take on it, knowing the controversial history of the USDA hardiness zone map.
On the face of it, the red lines on the map above simply mark a data-defined boundary. Below that line is the area where winter temperatures should be expected to stay above -10F. That’s based on the 30 years of local weather data, prior to the map date. As the U.S. winter nighttime temperatures have warmed, those lines are moving north about 5 miles per year, in Missouri. And, as I understand it, at roughly that rate, averaged across the entire U.S.
Back to the here-and-now, if you look at the illustration above and immediately say, hey, what happened to the circa-2002 map? Why did they skip a decade? Then you get an interesting story.
The answer is, Republican administration. The Bush Jr. administration just somehow couldn’t quite seem to get around to allowing the public to see the updated version of that map. The widely-held presumption is that they withheld the information precisely because it showed what I’ve highlighted above: the USDA hardiness zones are migrating north. That’s easily-grasped evidence of the early impact of global warming on the U.S. And so that information was suppressed.
(This, despite the nonsensical CYA language that the USDA insists on including in the footnotes to the description of the map methodology. They seem to say that “climate change” requires 50 years of data, and since each individual map only covers 30 years, you can’t infer that this is the impact of climate change. Despite the fact that the underlying span of data across the full set of maps is now more than 50 years.)
On the other hand, I think those changes ought to get more press coverage. This isn’t natural variation. This is a clear and understandable signal of global warming’s initial effects. And as slow as these changes are, relative to a human lifetime, there’s nothing on the horizon to suggest that they are going to stop any time soon. Five miles a year doesn’t sound like much, until you realize that the U.S. is only 1000 mile north to south, and that things will move a lot faster once global warming really gets rolling. And that it’s fairly hard to grow corn and wheat in a sagebrush and cactus desert.
So, even though I’m still in Zone 7, I think this deserves more press than it has gotten. And I think that the Bush-administration suppression of the circa-2002 map needs to be remembered, right alongside the temperature data.
Source: USDA. I removed some details from the map (e.g., degrees C scale) to make it clearer. Thus, I must say that: a) the map is not the official USDA Plant Hardiness Zone Map, and (b) the USDA-ARS and OSU logos are eliminated. If you want to see the full official map, follow the link.
The map above shows the coldest wintertime temperatures in each year, averaged across 30 years of data. The 2023 map literally uses weather data from 1991 to 2020.
The map provides guidance as to what perennial plants can usually be expected to survive the winter, unprotected, in each location.
That’s guidance, not certainty. As the owner of a lime tree, I am acutely aware that citrus trees will typically die back to the ground if they go below about 28F. Plausibly, you need to live somewhere near Zone 10 or higher (e.g., Florida) before you can expect your citrus trees to survive reliably, out-of-doors, unprotected. Even so, the occasional freeze will hit Florida, so significant frost damage to Florida citrus groves seems to occur every few decades or so (reference).
More generally, if you ever buy a perennial plant from an on-line nursery, they’ll let you know the hardiness zones in which the plant is expected to survive. Or they’ll give you information such as “hardy down to 0F”, and leave it up to you to know what USDA hardiness zone you live in.
It’s not hard to get your hands on the underlying data from which these maps were created, for example, via NOAA. I’ve plotted the annual wintertime lows before, for the weather station at Dulles Airport. Here’s 60 years of wintertime lows, as recorded at Dulles.
The obvious upward trend that you see above is pretty much the norm for most of the U.S. So it’s no surprise that the revised USDA map shows those plant hardiness zones creeping northward.
In fact, my location (Vienna VA) graduated from Zone 7A (expected annual low of 0F to 5F) to Zone 7B (5F to 10F). I was firmly in the middle of 7A, now I’m barely at the edge of 7B. That’s reasonably consistent with the increase in wintertime minimums shown in the Dulles data above.
One final footnote is that, due to the nature of C02-driven global warming, the northward creep of the hardiness zones exaggerates average warming.
The reason for this is simple: The largest impact of global warming is on nighttime temperatures. (E.g., via Scientific American). And on winter temperatures (E.g., via Axios). By inference, the biggest impact of all should be on nighttime winter temperatures. And, typically, the annual low temperature in an area is set during the course of some winter night.
If nothing else, knowing this is a quick way to dismiss denialist arguments that, somehow, the observed warming on earth is due to changes in the sun. (That, despite direct satellite measurement of solar irradiance, dating back to the 1970s, showing no such thing.) The fact is, the warming is more pronounced at night, and in the winter, both times of limited sunshine. Heuristically, if enhanced atmospheric C02 is a blanket, that blanket matters more when it’s cold and dark.
The real lesson here isn’t the map, per se. Anyone who cared to analyze the publicly-available weather data — as I did above — would already have a strong expectation that the official USDA climate zones would continue to move northward, in this most recent update of the USDA map.
Really, the big lesson here is the missing circa 2002 map. There was a time when Republicans so thoroughly insisted in keeping their heads in the sand, on global warming, that they found excuses not to update this map.
Has that changed? Are Republicans on board now, with the idea that global warming is real? I doubt it, but there’s no way to know. The last two iterations are both dated to periods with Democrats in control of the administrative branch of government. So, as to whether or not a Republican administration would allow this to be updated on a once-a-decade schedule, I guess we just won’t know until we see it. Or not.
At what point is an on-line deal so good that you decide not to buy it?
And if so, why?
In the modern U.S.A., with markets dominated by cheap Chinese goods, is there still any such thing as a price that’s too low to be believable?
I have to write this one fast, as this amazing deal I’m looking at won’t last long. I must order now, or I might miss out on the deal of a lifetime. Continue reading Post #1891: If the on-line deal seems too good to be true, what do you do?
Time to wrap up the 2023 gardening year. These are the highlights.
Continue reading Post G23-068: Life in mustard and okra, ten lessons from my 2023 gardening year.
That’s “lime & green tomato”, not “lime-green tomato”.
Unlike every other on-line recipe page on the planet, I’m going to give you the recipe first, then yak about it afterwards.
Continue reading Post #1864: Lime green tomato zucchini bread
