This is a transcript of the Gastropod episode, Buried Treasure: Weeds, Seeds, and Zombies, first released on October 11, 2021. It is provided as a courtesy and may contain errors.

MARJORIE WEBER: The map!

DIGGING SOUNDS

FRANK TELEWSKI: How appropriate, it’s snowing. Oh, shoot. I screwed up. It’s that way.

NICOLA TWILLEY: Okay, there’s clearly some kind of treasure hunt going on. But what’s the treasure?

CYNTHIA GRABER: Weed seeds!

TWILLEY: Wait, Cynthia, are we making another cannabis episode already?

GRABER: No, Nicky, two was quite enough, thanks. These are the other kind of weed, weeds. So maybe I should have said “weeds seeds.”

TWILLEY: But weeds and their seeds are not usually thought of as particularly treasure-like, honestly. Why on earth would you go out hunting weed seeds in the snow?

GRABER: That is a very good question, and one we’re going to answer this episode. You’re listening to Gastropod, the podcast that looks at food through the lens of science and history, I’m Cynthia Graber—

TWILLEY: And I’m Nicola Twilley. And this episode, we tag along on a weedy treasure hunt as part of the world’s longest continuously running plant biology experiment.

GRABER: And as we head out at 4am into a snowy Michigan dawn, we also wondered: What is a weed? Why is one plant something we cherish and another plant something to attack with all possible force?

TWILLEY: It’s kind of a twisted story, because even while we’ve been locked in this deathmatch, weeds have helped us and we’ve helped them, despite ourselves.

GRABER: But the results can be kind of disastrous on the farm. Researchers say that weeds are the biggest problem preventing crops from growing to their full potential both in rich and in poor countries. Scientists estimate that if American and Canadian farmers didn’t use weed-killing chemicals, they’d only produce half as much food.

TWILLEY: Even with herbicides, weeds cost 33 billion dollars in lost crops annually in the U.S. alone. Globally, even a lowball estimate of how much of the world’s grain production is lost to weeds is kind of staggering—it’s enough to feed millions and millions of people.

GRABER: Weeds are obviously a really big story and a huge issue, and it’s something we’re going to be coming back to. In future episodes, we’ll tell you the story of the biggest name in herbicides, that would be Monsanto, and the ways in which our dependence on products such as theirs has created superweeds, as well as what some of the tools are to manage those superweeds today. But for now, a weedy adventure awaits.

TWILLEY: This episode was made possible thanks to generous support from the Alfred P. Sloan Foundation for the Public Understanding of Science, Technology, and Economics. Gastropod is part of the Vox Media Podcast Network, in partnership with Eater.

PRE-ROLL

WEBER: This is the Beal seed experiment. It’s the world’s oldest continuing planet biology experiment, and it began in 1879, which is 142 years ago.

TWILLEY: Marjorie Weber is an assistant professor of plant biology at Michigan State University. And she’s one of just a handful of people in the world who have been let into the secrets of the Beal Seed experiment.

GRABER: Which had them digging far earlier than anyone should be awake.

WEBER: It was started by this scientist who was named William Beal. And William Beal was a contemporary of Darwin. He would write letters to Darwin and he was an early plant biologist in the United States.

TELEWSKI: And so he was doing a lot of work with farmers at the time. We are the first land grant institution in the United States, which means that we support agriculture as a core to our mission, our university mission. And Professor Beal would meet with the farmers around the state of Michigan, helping them to increase their yields and increase their productivity on farmland.

TWILLEY: And that is Frank Telewski, he’s a colleague of Marjorie’s in the plant biology department at Michigan State and he’s the senior scientist on the Beal experiment.

GRABER: 142 years ago, William Beal did something a little odd. He collected a thousand seeds each of 21 different weeds. That’s 21,000 super tiny seeds!

TWILLEY: He divided them up into 20 different glass bottles, so that each bottle had fifty seeds from each plant. Every bottle had a weed blend—50 seeds from each of the 21 species, for a grand total of 1050 weed seeds per bottle. And then he filled the bottles up with some quote moderately moist sand.

GRABER: Beal buried all of those bottles on campus about three feet below the surface, on a piece of land that had never been plowed for farming. The bottles were left uncorked, and their mouths were slanted down so that the bottles wouldn’t fill up with water.

TWILLEY: And then he filled up the hole, drew a map so he could remember where his bottles were, and went away for five years.

GRABER: And then he came back and dug one of them up, just one of those twenty bottles. But why?

WEBER: Beal was interested in how long agricultural weeds can hang out in the soil. And he was interested in this problem that farmers were having where they were feeling like they’re pulling the same weeds out of the soil every year. And they just kept coming. And it was clear that there were seeds hanging out in the soil. And he was interested in: how long can they hang out there? And so he planted these bottles to answer that question, how long can weeds live in the soil of agricultural fields?

TWILLEY: If you’ve ever tried to grow things, like veggies or even just a regular lawn, you know weeds can pretty much be the bane of your existence. For farmers, they’re even worse.

TELEWSKI: And in those days, they didn’t have large cultivating machinery like we do today, where you can go out and, you know, cultivate between the rows of crops to remove the seeds or spraying herbicides and doing herbicide treatments. Things were done pretty much by hand, or by horse and hand. And so it took a long time. You know, the old saying, “it’s a long row to hoe,” basically means, you know, you’ve got a lot of work ahead of you if you’ve got a long row to hoe. So. You know, I can see farmers probably asking Professor Beal, like, how long are we going to have to yank these weeds before we don’t have any more weeds coming up

WEBER: But I think William Beal also was just really interested in how plants worked ultimately. And it was a big mystery and it remains a big mystery how long seeds stay in the soil in what we call the seed bank.

GRABER: When I hear the words “seed bank,” I think about the places around the world that are saving seeds for the future. But that’s not what Marjorie is referring to—she’s saying that there are just a lot of seeds in the soil in general, in the seed bank, waiting to grow into baby plants.

TWILLEY: No one knows quite how many, and obviously it varies based on where you are, but the best estimate is a minimum of 120 million weed seeds in every single acre. Some estimates go as high as 1.4 billion seeds. In every single acre!

GRABER: And Beal set up this experiment to figure out just how long all those seeds can survive.

WEBER: We know that seeds can last a really long time in really pristine conditions. Like in very cold and very dry conditions. And we have, you know, instances, anecdotal instances of seeds that have lasted for thousands and thousands of years in the permafrost or in incredibly dry conditions. However, most seeds in the world are not in really dry and cold conditions. They’re in the seed bank. They’re just in the soil. And we don’t know how long they can last when they’re dealing with things like moisture and temperature fluctuations and microbes and all that stuff. And this experiment really gets it that.

GRABER: Microbes! Drink! And that’s one of the cool things about this experiment. The bottles are open, so moisture and oxygen and microbes can move in and out.

TWILLEY: So William Beal’s original plan, way back in 1879, was to dig up one of his bottles full of weed seeds every five years, and just see how many of the seeds still sprouted. The experiment was supposed to last exactly one hundred years.

GRABER: And then, about 40 years after Beal started his project, after seven bottles had been unearthed, Beal had retired, and the new scientist in charge of the project was like, you know, every five years plenty of seeds keep growing, so we should really extend the time between unearthing to see how long we can keep this thing going. So starting in 1920, they waited ten years between seed-bottle treasure hunts.

TWILLEY: And in 1990, which is actually after the experiment would have ended if they’d followed Beal’s original plan, the scientists at Michigan State said, some of these weed seeds are still coming up, let’s make this experiment even longer, and only dig up a bottle every 20 years. Which brings us to today.

GRABER: But to go back to the beginning of the experiment, how did Beal decide which seeds to put in the jar in the first place—how did he decide which plants are weeds?

RICHARD MABEY: There is no objective botanical description of weeds, it’s a cultural description.

TWILLEY: This is Richard Mabey. In case you’re not familiar, he’s a legend in my home country—he’s like a literary David Attenborough figure in the U.K. He’s a nature writer who has written a somewhat incredible 40—four-zero—books. Including one on weeds called Weeds: In Defense of Nature’s Most Unloved Plants.

MABEY: Basically, a weed is a plant that somebody doesn’t like. All kinds of definitions have been prescribed for weeds. One of them was, it’s a plant which nobody has found a use for yet. The most useful one is simply a plant in the wrong place, which is quite a kind of unemotional, objective description of the fact that some variety or species of plant has found its way into a place that somebody else objects to, and therefore calls it a weed.

GRABER: Sometimes those places are very far from the weed’s original home, and there are few or no natural competitors for it, so that’s one reason it might thrive and even maybe take over.

TWILLEY: But even though really the main thing weeds have in common is the thing we have against them, they do share some common characteristics.

MABEY: By and large, weeds thrive in areas of human disturbance. So classically, they’ve been in agricultural fields and gardens, in battlefields, on bomb sites, in industrial sites.

GRABER: But one thing to think about is that there really wasn’t such a category as weeds, at least not in the cultural sense, before we started farming.

MABEY: Before there was agriculture, before there was deliberate cultivation, which takes us back about, what, 8, 9,000 years in human history, there couldn’t by definition, be such a thing as a weed, because there were no cultivated crops for any wild plants to intrude into. So weeds as a cultural category began with cultivation.

TWILLEY: But that’s not the only reason that weeds and agriculture go together hand in hand—they’re like two sides of the same coin. Because the whole history of farming is disturbing the soil.

GRABER: Think of a farm, you might have had a plow in the past, maybe a tractor today, but one thing is for sure, it is generally a field of torn up and turned up earth. Which makes them perfect for weeds.

MABEY: A lot of the things that we understand as weeds began their life in the wild as denizens of very unstable, disturbed places, things like floodplains, volcanic scree, anywhere where the soil is in a state of permanent disturbance and plants have evolved to cope with that. So as soon as humans started creating disturbed soils as a part of their advance toward civilization, these canny plant species jumped in, finding these places were exactly like the ones that they’d evolved in the wild.

TWILLEY: I mean, who can blame weeds for not realizing we hadn’t disturbed all that soil just for them. But actually, Richard says the relationship between weeds and farming goes back even further. Obviously our crops are descendents of weedy plants—after all, the things we grow for food thrive in disturbed soil.

GRABER: And then those weedy plants actually helped make our kind of weedy early food plants better.

MABEY: Just before agriculture, in the kind of late Mesolithic, the late hunter gatherer stage, there was a period when hunter gatherers began to form settled communities just for short periods of time.

TWILLEY: And a key element of any settled community is somewhere to put the trash: a midden, as they’re called by archaeologists. That trash pit would have ended up a mix of human waste, bits of food—vegetables and grains that had been discarded.

MABEY: And any kind of plants that they weren’t interested in. And it’s in these middens, well-fertilized, pretty disturbed pieces of ground where interesting cross-pollination started to occur. So in that kind of melting pot of gathered plants and weed plants, new varieties that were to become the cultivated plants of the future began to emerge. So weeds even at that stage had a pretty crucial role in reinvigorating the gene pool.

GRABER: The early farmers wandered out to the middens and found tastier, hardier, basically better crops for us to eat!

TWILLEY: And have we ever thanked the weeds for that? And that’s not all weeds have done for us. Richard doesn’t think agriculture itself would have made it without weeds. Because without weeds, the thin soil of the Middle East would have vanished before farming became a way of life.

MABEY: I’d come to regard weeds as kind of the sticking plasters of soil. We may deride them, but if they weren’t growing in some places, the soil that we are trying to cultivate would just be blown away.

GRABER: But just which plant was a weed and which one was a crop?

TWILLEY: That hasn’t always been so clear.

MABEY: The line has been fantastically porous both ways. So things which were denigrated as weeds at one time, have later become cultivated plants. Cultivated plants become weeds when they become too successful and aggressive. So the flow is both ways.

TWILLEY: Richard says oats and carrots both probably became crops by first growing as weeds among existing crops. Farmers noticed them and saw their potential, and so they elevated them from weed to crop.

GRABER: And some plants that once upon a time had been cultivated as food eventually fell from grace.

MABEY: Well, there’s a global weed called fat hen. And it got in very early into cultivated crops. But it was rather treasured there, certainly, in Europe in the Middle Ages. It was deliberately fostered as a leaf vegetable. It’s actually rather delicious. It’s a little bit like a rather tiny spinach. I’ve eaten it often myself. So that plant was valued for its culinary virtues. But increasingly, as agriculture became more intense, its persistence in fields of things like sugar beet, a very close related family, became obnoxious to farmers. So it became reclassified as a weed rather than as a pretty useful intruder.

TWILLEY: But even though the line was porous, weeds as a category have always been categorically bad. They’ve literally been demonized.

MABEY: Yeah, a lot of weeds were attributed to the devil. I mean, you can go through the English folk names of plants as I’m sure you can in the United States, and find many that are literally devils weeds or devils worts.

GRABER: But of course this demonizing weed trend didn’t start with the English coming up with plant names. Richard told us you can see images of hoeing to get rid of weeds in ancient Egyptian wall paintings. And in the story of the Garden of Eden, one of the points is that Adam and Eve were cast out of the garden and no longer had easy access to food, they had to work hard and contend with thorns and thistles.

TWILLEY: And we’ve been contending with them and bemoaning their existence ever since. There are even royal proclamations outlawing particular weeds, going back centuries.

GRABER: But these laws haven’t been particularly effective. And in fact most of what we do isn’t great, and actually often ends up helping weeds grow better. Richard told us this is a process that’s been going on probably since like the earliest days of agriculture.

MABEY: One of the early ways in which weeds were eliminated was by putting the seed corn of the next year through some kind of filter, some kind of sieve, which would only permit the seeds that were the correct size for the crop to pass through.

TWILLEY: Obviously the hope was that the weed seeds wouldn’t go through, and you’d be left with just the crop.

MABEY: But of course, seeds are highly variable in size, and those weed seeds that just happened to be the same size as the crop seeds went through. And so the process of sieving had effectively guaranteed the survival of that genetic strain of the weed whose seeds were the same size as the crop seeds. So they went on into the next generation, and many generations after that, as well.

TWILLEY: Sneaky sneaky. This back and forth where we came up with different ways to eliminate weeds and then they end up backfiring because the weed adapts—that still continues to this day.

MABEY: One of the most dramatic examples of that occurred in Southeast Asia when they tried to introduce a discriminatory factor in rice crops, some of the weeds of rice crops, some of the wild grass and rice species that grow with rice crops look almost identical. So there was an attempt to genetically tweak the rice crop. So they had a slight pink hue and could be picked out by the weeders and left. But of course, inside the genetic variety of the wild weedy grass and rice crops, there was also pink tinges.

TWILLEY: So for a little while, this worked: the rice was pinkish and the weeds mostly weren’t. And then, because all the weeds that weren’t pinkish got removed, the pinkish weeds took over.

GRABER: Foiled again! One of my favorite examples from Richard’s book isn’t actually about agriculture, it’s about lawns. He writes that our lawn mowers cut grass to a certain height, and so the unwanted plants that now thrive on American suburban lawns are all just under that height so the lawnmower can’t hack them down.

TWILLEY: Those pesky weeds. But you have to admit, this adaptability is pretty impressive even when you’re being frustrated by it. Darwin was fascinated by the fast-track evolution of weeds. He kept a weed garden at his house in Kent where he carried out the first real experiments on the competitiveness of weeds—starting with which ones came up in the plain dirt patch he dug up.

GRABER: There are a lot of things that help weeds thrive in a disturbed patch like Darwin’s. Plants we consider weedy can produce a huge number of seeds—one weed called mullein, which is one of the ones Beal put in his bottles and is still considered pretty nasty today, each full-grown plant can produce around 400,000 seeds. Wheat only produces about 100 seeds per plant.

TWILLEY: Another weed that’s in the Beal bottles and is still considered a weed today, although it’s not necessarily as problematic as it was back then, is called shepherd’s purse. And it has a super ingenious technique for success—its seeds are coated in a thin gummy film like the seal on an envelope, and when that film gets wet, it becomes sticky, so it sticks to the feet of birds and spreads far and wide.

GRABER: Some weeds survive by acting really quickly. Tumbleweed seeds, for instance, can germinate in just 36 minutes when the time is right. But some weeds survive by taking it really really slow—this approach is called dormancy. They kind of hibernate in the soil.

MABEY: And dormancy is probably a characteristic of all plants which live under unsettled conditions. It’s to a plant’s advantage to gradually evolve seeds which have this capacity.

TWILLEY: This ability to just sit in the soil and not germinate for years and years and then one day pop up—it’s one of the keys to weeds’ success. And one of the ways they drive farmers completely mad. If you think about it, if you’re a plant, having your some of your seeds able to germinate and take their chances on the field the first year, and some kind of sitting on the bench or in the soil, in reserve, able to go out and compete years later when conditions might have improved—it really boosts your odds of surviving to the next generation.

GRABER: Beal and Darwin were in touch at the time, and this question of how long weed seeds could hang out dormant in soil before springing back to life—this is exactly what both of them wanted to know, what Beal set up a project to figure out, and what Marjorie and Frank and their colleagues headed out into a cold Michigan dawn to discover. Coming up after this word from our sponsors.

MID-ROLL

WEBER: It was late—well, it was early Thursday morning. So I woke up at 3 a.m., I put on a wool sweater, you know, some long underwear. It was cold, it was raining and sleeting a little bit. And I snuck out of the house quietly—trying not to wake up my family. I drove to a secret rendezvous point on campus and met up with the rest of my science colleagues that are part of this secret experiment. And we pulled out the map and we went to the location where the bottles are buried.

TWILLEY: All this cloak and dagger business is partly because the way Beal set up his experiment is that the location where the seed bottles are buried is not public information. For the sensible reason that the experiment would be completely ruined if random people decided to randomly dig them up.

WEBER: These bottles are not worth anything. You know, they’re not expensive, but the science is really worth something. And we just don’t want people going out and searching for them.

GRABER: Nobody outside a special tiny circle is allowed to know the location.

WEBER: We’re not allowed to tell friends and family where the seeds are.

GRABER: Of course there’s a problem with keeping the location secret—universities build new buildings all the time. That happened to another long-term experiment.

WEBER: There was a similar seed experiment at Ohio University and it was put in the ground after the Beal experiment. There were enough bottles there that they were going to be dug up until like 2900 or something like that. And they totally built a building on it.

TWILLEY: And that was it. The experiment was lost.

GRABER: They’ve guarded against that happening at Michigan State.

TELEWSKI: The good news is that the folks who manage the campus in terms of development, the folks in infrastructure, planning and facilities, know where the bottles are. The people who need to know where the bottles are, know where the bottles are.

TWILLEY: So, good, someone on the Michigan State facilities team knows at least roughly the general area not to dig. And then traditionally, a map has been handed down from one scientist to the next to show them exactly where to dig, when it’s the right time to unearth another bottle.

GRABER: Frank was tapped back in 1999, a year before a bottle of seeds was unburied in 2000. He was only the 8th scientist ever to guard the secrets over the past century, and he’s still the guardian of the experiment, but he’s already appointed his successors.

WEBER: Traditionally it’s been passed down from one person to another. But this time, Frank Telewski decided to pass it on to three people.

TWILLEY: Originally, Frank just chose one person, his colleague David.

WEBER: He chose David Lowery first, and came into David’s office and said, Can I show you a map? And then, I think it was like a matter of months later that Frank had his stroke. And so if Frank had not done that and if, you know, things had turned out differently, then that would have been the end. There’s no way we would have been able to find them.

GRABER: Frank has fully recovered and he’s doing really well.

WEBER: But it was kind of this reality check of like, wow, he almost didn’t pass on the information and the map right before that happened. And then he kind of was like, I think we need to have more than one person, two at a time at least, knowing where these bottles are.

TWILLEY: Close call.

GRABER: But even with the map—and with a larger team reading the map—there isn’t a huge sign on the ground to tell you where the bottles are hidden.

DIGGING SOUNDS

TWILLEY: On a cold spring morning earlier this year, Marjorie, Frank, and the rest of the crew started digging where they thought the bottles should be.

WEBER: We’re so excited. Yeah, you are getting down there. That’s like 13 inches.

MAN: OK, let me go in with the hand trowel. There’s a sand layer. Please be here, please be here.

GRABER: They dug for a while—down to the depth that according to the map, the bottles should have been

WEBER: We’re kind of like looking for the bottles, we’re looking for the bottles. And it became clear like, oh, man, where are the bottles? We could not find them.

TELEWSKI: Oh, shoot. You know what? You’re right.

WOMAN: What did we do?

TELEWSKI: I screwed up. It’s that way. I was hoping we could hit it on a first try. Semi-embarassing, but 20 years was a long time ago.

TWILLEY: In the confusion of the early hour and the darkness, Frank had got turned around. They had been digging in the wrong place.

TELEWSKI: And usually I’m a much better map reader than that. So it was a little frustrating, a little embarrassing for me.

WEBER: So then we had to dig a new hole. At this point, you know, the birds are starting to chirp and we’re starting to get pretty stressed out that we’re not going to find the bottles. People were getting really cold, morale is very low at this point.

TELEWSKI: It was kind of chilly, but it wasn’t terrible. You know, it’s a Michigan spring morning.

WEBER: We’re taking turns digging. And it happened to be my turn to dig. I was on my belly lying on the ground with my whole upper body in this hole, like covered in dirt. I was using my hands to sort of sift through the sandy soil because at—once you get close down to the area where the bottles would be, we didn’t want to use a shovel anymore because we were afraid we would break the glass of the bottle with the shovel and then like you would be the person that ruined the experiment after all 140 years, like my nightmare. OK, OK, Marge, don’t mess this up.

WEBER: So we think they’re right here. SCRAPING SOUNDS Ohhh, I think I found it. CHEERING Oh, it was a rock.

GROUP: Noooo!

WEBER: Yeah, I’m serious. I’m sorry. It was a big rock. I don’t know why Beal would put a rock down here.

WEBER: I found a rock at one point and I announced that I had found the bottles and everyone was like, Yay! And then I was like, Oh, it’s a rock. And then people were like swearing. It was very dramatic. And then, then I found them and I didn’t want to. It was like the smooth clear—it was clearly a glass bottle under there. And I didn’t want to announce it until I was like, totally sure. So I was feeling and I had this kind of big grin on my face, my head in this hole.

WEBER: Okay, now I for real found it.

MAN: Yeah?

WEBER: Yeah, I definitely did. Yeah, look at that!

TELEWSKI, SINGING: And in the naked light I saw, half a dozen bottles, less not many more.

WEBER: It’s not a rock! It’s not a root. It’s a glass bottle. You can reach down there and touch it, Frank, if you want to. Don’t throw your back out.

TELEWSKI: Wow!

WEBER: Yeah.

TELEWSKI: Ohhh, wow. Hello, bottles! Ohhh thank you.

WEBER: And I said, I found them, and everyone cheered, and I got out and before I excavated the bottle, I let everybody on the team just kind of like get in there and see it in the ground and look at it, because everyone, there’s just a big sense of relief of finding it. And it looked really cool nestled in there. You can see it. Like it was buried treasure in there.

WEBER: Yeah, seriously. Okay, so should I just carve it out? Like I’m an archaeologist? Okay.

TELEWSKI: The Monty Python seeds. IN A HIGH PITCHED VOICE I’m not dead yet! I’m getting better! I’m going to sing! LAUGHTER Oh thank God.

GRABER: These are small bottles, narrow and maybe a half a foot long. They’re flat, kind of like a glass whiskey flask, and they look like they’re full of sand. Remember, each one bottle has more than 1000 seeds in it, there are 50 of each of the 21 species of weeds. Marjorie left four bottles in the ground and slowly, gingerly excavated one.

WEBER: The bottle is open at the top. And so when you pull it out, you have to be really careful not to pull—or not to spill the contents, because it’s kind of sideways lying in the ground.

TWILLEY: Then the seeds got carefully taken back to the lab and carefully planted and watered and set up in a growth chamber. And the team got to go home and shower.

WEBER: I walked into my house. My kids are having breakfast at the dinner table. Like they had just woken up and I’m covered in mud. And my four year old daughter is like, Mom, where were you? And I was like, guess what? I was out in the middle of the night digging up a bottle that’s been in the ground for over 100 years and it has seeds in it. We’re going to plant the seeds, we want to know if they still grow after 100 years. And she was like, What did you really do? LAUGHS And she didn’t believe me. She’s actually been mad at me like all week because she keeps asking me, Like, what did you really do? Like, why won’t you tell me? And I keep telling her, That’s what I really did. Like, that’s my job. I did that as part of my job. And she’s like, No.

GRABER: If you happen to be listening, it’s true, that’s what your mom did! So, we mentioned before, there are 21 different kinds of seeds in each bottle. Some of them aren’t a big deal these days, like evening primrose and clover, which some farmers are now sowing on purpose in their crop rotation.

TWILLEY: But lots of them are still problematic today. Ragweed is in there—that’ll be well known to those of you who suffer from allergies, but it can also reduce the yield of a field of soybeans by up to a third. There’s one called malva, or round-leaved mallow, which sounds kind of lovely, but it outcompetes other crops for light and water, and it’s resistant to most herbicides.

GRABER: Over time, nearly all the seeds have stopped germinating. The only one that germinated fairly quickly last time, twenty years ago, was a plant called mullein, which as we said is still considered a nasty weed today.

WEBER: However, we know that some seeds need different conditions to germinate. Like some seeds need to go through two winters to germinate. They need to get the conditions to germinate twice, basically.

TELEWSKI: I know what Jan Zeevaart and myself, after we did the initial germination, we exposed the seeds to an artificial winter for six weeks and then we put them back in the growth chamber. And lo and behold, that’s when the Malva germinated. And the Malva hadn’t germinated for probably I think it was like, you know, 90 years or something like that, before we got to see it germinate.

TWILLEY: One of the weeds is called American burnweed, and as the name implies, it does well in landscapes that have been burned. So this year, for the first time ever, one of the Beal team is going to apply a smoke treatment to the seeds, to see if they can persuade any burnweed to germinate. The last time that came up was nearly a century ago, so it will have been gone a while.

GRABER: And they also have other new tools to try, even if absolutely nothing germinates, either in the first attempt, or with the double winter, or with the smoke. For instance, they want to try to find some zombies.

WEBER: And once in the cold room, Margaret Fleming, who’s the seed scientist in our group, dumped out a little bit of the sand into a petri dish and sorted through. And she pulled out a couple of seeds of a species that hasn’t germinated in about 100 years. And she’s going to look to see if those seeds are truly dead or if they are what we are calling zombie seeds, which is that they’re still like, you know, doing a lot of the stuff seeds do inside. Like they’re still biologically active, even though they can’t quite complete the process of growing into a plant.

GRABER: But meanwhile, the team is just constantly checking on what they hope might, just might, push up out of the soil and turn into a baby plant. Within a week, they should have an answer.

WEBER: There’s a time lapse photography set up on them, which is kind of fun this time. And we’re just peeking in on them every day, making sure they have the right level of moisture. And then we’re waiting for them to start growing. And it could be that this year is the year that nothing germinates. Like maybe we’ve reached the end of the longevity of these species. And that would also be really interesting. I mean, I think some people might be disappointed when they stopped germinating, but I think it would also be really neat to have an answer to how long these things stay alive in the soil.

TWILLEY: It’s funny though, in a way, everyone’s rooting for the weeds!

TELEWSKI: We don’t know what’s going to germinate. We hope something germinates. I hope that my colleagues who are taking over the stewardship of the experiment have the same opportunity I had 20 years ago to have that excitement, to walk into that growth chamber and see tiny little seeds sprouting. I remember that, that was probably, for me, the most memorable moment.

GRABER: So, will the weeds sprout again? Coming up after this break.

MID-ROLL

DAVID LOWRY: We’ve now reached the outer door, which contains our growth chamber. DOOR SQUEAKING OPEN, BACKGROUND HUM There’s something germinating in the Beal seed experiment! This is—oh my gosh, I didn’t expect to see anything today. This is—wow. Oh my God. Okay.

TWILLEY: This is David Lowry, he’s another of the Guardians of the Beal Seeds. And he was the lucky one who spotted the very first little tiny green shoot from one of the seeds, 8 long and tension-filled days after they dug them up in the middle of the night.

WEBER: He sent a picture around and we all—you know, I’m sure, opened it immediately and gazed at it. And then there was this flurry of emails back with things like “Woooo” and “Yay seeds” or “We have seedlings!”

TELEWSKI: Yeah, I think my email message was all caps, “WOOHOO!” LAUGHS

WEBER: So we were all very excited. And then all of us got to go over, over the next chunk of the next 24 hours or so, and check them out and stare at them.

TELEWSKI: To see a little plant poking its head up and spreading out its two green cotyledons to start taking advantage of the light and photosynthesizing, after being buried in the soil for a 142 years is pretty amazing. I mean, you know, Professor Beal himself counted that seed out amongst 50 others and placed it in the bottle. And then, never to be seen by human eyes again until now. So it’s, it’s heady. It’s really neat.

GRABER: The first seed that germinated was the same plant that first germinated 20 years ago, mullein—its scientific name is Verbascum.

TWILLEY: By the time we followed up with Frank and Marjorie, there were already eight little baby weeds. And a few days later, there were 11, And by now, after the cold treatment, there are 20, one of which seems to be a different species.

TELEWSKI: And we want to put those seedlings into the greenhouse that have germinated and grow them up, get a positive ID on them, that’s very critical, and also allow them to flower and collect seeds off of them.

GRABER: They’ve certainly already learned something about how long these species can lie dormant and then bloom again. But that’s just the beginning.

WEBER: We’re going to do a lot of things, I think we’ll probably make herbarium specimens with some of them. We will save tissue from some of them so that we can do things like look at their DNA if we need to get a better ID on them using molecular techniques. We’re also interested in the morphology of the plant. Do the flowers look different than the modern individuals that are growing now? In other resurrection experiments, they have seen differences in the flowers over time. Some of those have been a lot longer than you know, than the one we’re looking at. I think the 32,000 year old seeds that they found in the permafrost in Siberia, those, the flowers had evolved quite a bit. That’s quite a bit longer time but, you know, there have been a lot of generations that have gone on for the species in between when the bottle was put in the ground and now. So there is opportunity for evolution to take place over that time.

TWILLEY: All still to be revealed. But so far what they can say is: mullein has some pretty impressive dormancy skills. 20 out of the original 50 seeds that Beal put in those bottles in 1879 have come up in 2021!

TELEWSKI: Well, there’s a seed that’s been hibernating for 142 years. What can we learn? And maybe by studying Verbascum, we can actually begin to address and answer those questions about long term metabolism in those seeds.

GRABER: This is really exciting science. And Frank and Marjorie and their colleagues are already bouncing around the idea of setting up another long-term study, but they’d do it a little differently this time. They’d first set up the baseline germination, they’d figure out what percentage of mullein seeds or any other ones would germinate the first year after they’re planted. That’s something Beal didn’t do. They’d also plant two sets of bottles in parallel, where one set is used to study germination and one set, the seeds themselves, are studied without germination, doing DNA analyses and so on.

TWILLEY: But, even though there’s a lot to be learned, Marjorie told us that it’s hard to do this kind of science. Most funding is targeted toward immediate results. That’s how science moves forward and how professors get tenure and how research mostly works. It’s easy to forget that long term experiments have value too—they can teach you something about the world you can’t learn any other way. That’s why Beal’s Seeds are unique compared to any other plant biology experiment.

WEBER: We have something in this experiment, which they can never have, which is just time. Like they can do all sorts of fancy experiments with all sorts of fancy tools. But they can’t make time pass faster than it just passes.

GRABER: And assuming, well, assuming no absolute catastrophe, they and their scientific successors will have that Beal study for another eighty years, 20 years for each remaining four bottles.

TWILLEY: Like we said, a lot of the seeds in Beal’s bottles are still problematic today. Some of them have since developed resistance to modern herbicides, many of them are listed as noxious weeds under state and federal law. So quite a few of them are still frustrating farmers a hundred and forty plus years after Beal buried his bottles.

GRABER: Weeds have a way of just getting under your skin. You have an idea of what you want to grow—sometimes it’s what you need to grow to make a living, sometimes it’s just what you want to surround yourself with in your garden—and those weeds really don’t give up. Even Richard who’s a champion of weeds sometimes finds himself a little put out.

MABEY: CHUCKLES The only plant that I get enraged about is ground elder, or grelder as we call it in this household, trying to make it sound like a medieval witch. And that is a weed and a half. Because it is ineradicable and it does smother any small garden plants that you want to grow.

TWILLEY: Grelda aside, Richard knows that, fundamentally, it doesn’t make sense to fight weeds to the death. But, since Beal buried his bottles, that’s precisely what farmers have tried to do. Industrial agriculture has just escalated the fight with toxic herbicides. Those worked for a while, but weeds are increasingly becoming resistant to all our chemicals—they’re super weeds.

MABEY: Just upping and upping the stakes against them has simply, as you say, produced superweeds. So we have to learn to live with them in much more intelligent, and let’s hope productive, ways.

GRABER: Richard had one idea of a solution to offer us, a way to live with weeds, which is an approach to farming and to gardening called permaculture. Basically it’s an approach to cultivation that treats a field as an entire complex ecosystem, not a monoculture.

MABEY: That is, you put plants or seeds in with minimal tillage. And you only control the weeds to the extent of, let’s say, topping them so that they don’t produce too many seeds. That stops weeds evolving to be fiercely competitive, and it allows them to do the valuable bits of their job, which is fixing nitrogen for the soil, fixing CO2 for the soil, helping to circulate nutrients, helping to establish mycorrhizal networks under the ground for the cultivated plants to tap into. So permaculture, as a method of producing crops, relies on not trying to drive the weeds into extinction, which invariably as we’ve seen results in them just getting cleverer. But instead, trying to learn to live with them, reducing their competitiveness as much as you need to, but not more than that, and hoping that their contribution to the piece of land in which they’re growing, their many contributions, will actually be beneficial to the crop.

GRABER: Richard’s being positive about what weeds can contribute to a field, and they can contribute these benefits, but they can also be a real pain. They can grow faster than what you want to grow and shade it and keep it from getting enough sun.

TWILLEY: They can use up soil nutrients and water and prevent them from going to the plant you want to grow. Some weeds even put out chemicals through their roots that are harmful to the crops they’re growing next to.

GRABER: And some weeds are themselves toxic to us, and if they happen to be growing among crops and we accidentally eat them, well, that’s not so great!

TWILLEY: We can’t live in peace and harmony with all weeds. Still, for Richard, once we stop fighting weeds tooth and nail, and learn to live with them where possible—once we stop expecting to be able to get rid of them, and instead work out how to manage them for the best—well, then maybe we can actually appreciate them. Or at least respect them. After all, we have a lot in common.

MABEY: We were an invasive species, we are an invasive species. We have traveled across the planet, away from the environment where we first evolved in Africa. We are the original invasive species. So there are many ways in which humans as a mobile, cosmopolitan, traveling species are similar to weeds.

TWILLEY: Also like a weed, Homo sapiens outcompeted and likely contributed to the downfall of other early humanoids. And our impact since then has hardly been limited to our own kind.

GRABER: We’ve also caused the disappearance of a lot of other animals and plants as we take over ecosystems. And the crops that we plant in monocultures all around the world are also kind of like weeds themselves.

MABEY: Because if you look, if you came from outer space, and looked at these plants, you would say they were the most successful weeds on the planet. Because they’ve managed to get everywhere, to be looked after everywhere. The way they are not like weeds, of course, is that we don’t call them weeds, it’s as simple as that.

TWILLEY: This more philosophical mindset can be hard to adopt when you feel like your food supply is being threatened, but maybe it’s the key to a better relationship with weeds.

MABEY: Sooner or later, we’ll have to find an alternative way of coexisting with them. And I don’t think in any field of, I won’t say human endeavor, but of living endeavor, the idea of trying to wipe out your competitors ever ends happily.

GRABER: And maybe they even have something to teach us.

MABEY: I suppose one could view them as exemplars of adaptability, of a willingness to make the best of very sad, bad situations, a tremendous frugality in eking out resources, in recycling, they are some of the most economically efficient organisms on the planet, and maybe that can be a lesson.

TWILLEY: OK, we may not be doing another weed episode but we are definitely doing another weeds episode. This story is not over. And not just because we haven’t used the M word yet. Monsanto, I mean.

GRABER: Stay tuned, more weeds to come. Also, we wanted to give a shoutout this episode to some of our newest special Gastropod superfans, who support the show at a particularly high level: Demi Vis, Avi Velez, John Yurek, Kim Behzadi, Jordan Bar Am, Jonathan Harris, and Marissa Finer. Huge, huge thanks to you all. As you know, we have a strategic partnership with Eater and Vox, but we are still totally independent—they don’t pay our salaries, we rely on you. If you listen to other similar shows, you’ll hear a staff of maybe eight to ten people, but Gastropod is just the two of us, with our part-time producer Sonja Swanson—so thanks to all of you who can help support our work in whatever way possible.

TWILLEY: And a huge thanks to Marjorie Weber, Frank Telewski, and the team at Michigan State, as well as to Richard Mabey, and to Rob McFarlane for connecting us. We have a link to Richard’s brilliant book, Weeds, on our website gastropod dot com.

GRABER: We will be back in two weeks with tales of candy that’s supposed to be… corn? Peanuts that taste like bananas, and the history of trick or treating. ‘Til then!