32: Plant Propagation Transcript
Hallie: Hello and welcome to One to Grow On. A show where we dig into questions about agriculture and try to understand how food production impacts us and our world. My name is Hallie Casey and I studied and currently work in agriculture.
Chris: I’m Chris Casey, Hallie’s dad. Each episode we pick an area of agriculture or food production to discuss and this week we’re focusing on plant propagation.
Chris: All right. How do you propagate a plant?
Hallie: So many ways.
Chris: You plant it in the ground or you cut part of it off and splice it into another plant and that’s why speciation is all just made up nonsense because you can splice all the plants with each other and create new plants.
Chris: No? You can cross breed them.
Chris: Okay. But the splicing, isn’t why speciation is nonsense.
Hallie: We don’t really call it splicing. We call it grafting. You basically build a plant, but it’s still two separate sides of the plant. Like you can graft a potato and a tomato together and what you have is a topato or however you like.
Hallie: The bottom part grows potatoes and the top part grows tomatoes. Right.
Chris: But it’s not a hybrid.
Hallie: Yes, it grows and then it dies and that’s it. It’s not going to produce a new plant because it’s not in the genes. Basically, what just happens is the tubes connect and so they can transport water and nutrients up and down the plant.
Chris: Okay. Cool. But that’s not propagation.
Hallie: It can be part of propagation, but that’s not mostly what we’re going to be talking about. A peek behind the curtain, I taught this as a class. Big shout out to one of my previous students who took our listener’s survey.
Chris: There you go. Hey, Melissa.
Hallie: Yeah, she’ll know all of this information hopefully. I taught a class called plant propagation and I thought it would be fun to try and fit an entire semester into 35 minutes of podcast.
Chris: If you don’t know all the information by now, Melissa, you should have paid more attention in class.
Hallie: Okay. We don’t need to drag Melissa on the podcast.
Chris: I never paid attention in class.
Hallie: Melissa was an excellent student.
Chris: I believe it.
Hallie: We have sexual propagation and asexual propagation.
Chris: It’s like hot or not.
Chris: [Laughs]. Plants that are hot for each other. Plants that just don’t care and do their own thing.
Hallie: No, we propagate plants to serve our own purposes not necessarily to serve the plant’s purposes. Most plants that we asexually propagate can propagate sexually, but there are reasons why we choose to asexually propagate it instead.
Hallie: Because plants are living beings that have sexual cycles and reproduce via pollen and ovaries and they create seeds.
Chris: There is still some [inaudible].
Hallie: It’s just like how many, many living things operate, including plants.
Chris: When you say we choose to propagate them, asexually I feel like we’re subjugating them to our will against their preferences, even though they are plants and they don’t necessarily have preferences. I’m like, oh, we are bending these plants to our will.
Hallie: Yeah, we do that with most things. [Laughs].
Chris: That is true. We are humans. That is what we do.
Hallie: It sucks to suck.
Chris: [Laughs]. I don’t think we need to drag all of humanity in the show.
Hallie: No, I’m not dragging all of humanity. I’m like sucks to suck to like all the other living plants. Maybe you should have thought about that and then become the dominant predator, apex species or whatever.
Chris: So because they didn’t work hard enough at evolution, they just have to deal.
Hallie: Yeah, I’m just saying. It seems like we got here and we’re crushing it.
Chris: I feel like that’s a little heartless.
Hallie: Nothing’s going wrong. We’re doing a great job. We have sexual propagation. We have asexual propagation. Sexual propagation meaning seeds. That’s how we further that plant. That can include things like seed breeding, which is where we grow plants for the purpose of trying to make a seed that will grow a better plant.
Chris: Seed breeding, which we grow a seed for the purposes of trying to make a better plant.
Hallie: We grow a plant for the seed in hopes that that seed makes a better plant.
Chris: We grow a plant for the seed. Oh, so we select for a particular plant that produces the best seeds.
Hallie: Basically, sometimes we have plants that are crossbreeds or hybrids and so in that, we can be growing tomatoes, but if we’re growing like seed tomatoes, then we’re never growing those tomatoes really for the tomatoes, we’re growing them to cross pollinate them and create tomato seed.
Chris: Kind of like when your mom and I got together because we knew we would make the best children.
Chris: It’s not gross. It’s romantic and sweet.
Hallie: No, it’s not at all.
Chris: All right. Fine whatever. We’re selecting plants to have better or more resilient seeds or we’re selecting them for some particular characteristic to qualify as whatever good is for what we need it.
Hallie: Right. We breed plants. Oftentimes when we do that, it’s seed breeding that we do it for. There are different components of a seed. You have the seed coat, you have the endosperm, the cotyledon and the embryo. I feel like we’ve talked about this on the podcast before.
Chris: Those are all words that I remember. Cotyledon is the weirdest one. I do remember you talking about it.
Hallie: Inside of the seed, there’s a little embryo, which is what the plant becomes, but there’s also these cotyledons that become what you first see, when the little embryo pops up. It’s like two or one leaves. They’re not really leaves because they’re inside of the seed. They’re like a starchy reserve so that when the embryo starts to grow, it’s able to like pull starches out so it has energy. This is helpful to understand the different parts of a seed because sometimes we have to treat seed in order for it to grow.
Chris: Are these what microgreens are?
Chris: I remembered another thing. I’m so happy for me.
Hallie: That must have been when we talked about it. If you want to go back, we talked about microgreens on the last superfood episode.
Superfood four I think we talked about microgreens and that involves talking about cotyledons, but around the seed is a seed coat. Sometimes when we are planting seeds, in order to propagate a new plant, we have to treat the seeds because there is something that makes it impossible for the embryo to actually grow. We do things like imbibing the seed, which is where you soak them in water.
Chris: It’s not about just getting them drunk.
Hallie: We don’t get them drunk. We can soak them in water by imbibing them. We can also stratify them, which is when we put them in the freezer for a couple of days and that will break a seed’s dormancy or we can also what we call scarify the seeds, which is where you basically file them down with like a nail file or something.
Chris: I’m so confused right now.
Chris: I’m accepting what you’re telling me, right? We’re talking about getting the seed to start growing, one of the ways is soaking them in water.
Chris: They don’t drown obviously.
They just like the water and the other way you said it’s freezing them, which I associate freezing with going dormant, not with triggering production.
Hallie: Right. Basically, what you’re mimicking there is if you’re a plant and you produce fruit in the spring time and it’s lovely and it’s warm outside and the seeds go in the ground, you don’t really want those seeds to start growing until the next spring usually. So you’re basically mimicking a winter time period so they have a freezing. Then when that freeze ends, they’re like, okay, great. It’s warm now I will start to grow. Because if it was still cold or if it was still warm and there hadn’t been cold, these seeds are like, wait, it’s going to get cold and it’s going to get rough for me. I got to wait it out.
Chris: The freezer mimics the weather.
Hallie: The seeds are not that smart. They can’t notice that it’s inside of a freezer.
Chris: Fair enough. Then taking a nail file to them.
Hallie: Yeah, scarification. Sometimes we just put them in a big tumbler and we tumble them around so that the seed coats get scratched.
Chris: Like a rock polisher.
Hallie: Yeah, but basically this is mimicking being eaten and then pooped.
Hallie: Sometimes you actually have to ferment seeds to make them grow, which is wild. But usually, if you have some kind of seed with a really hard seed coat, it’s either meant to be a mammal, grabs it and then chews it and then spits it back out or it goes through the digestive system and there are a lot of acids in there that can break that seed coat down and then it’s ready to be.
Chris: Got it. The nail file mimics the process by which the seed coat gets broken down. There are seeds which in the wild go through a fermentation process before they start growing. Is that correct or is that scaring as well?
Hallie: Yeah, fermentation is kind of similar. That’s basically mimicking going through a digestive track where you are exposed to a lot of high acids.
Hallie: That is most of what I have for sexual propagation.
We can talk about asexual next, which is the wild stuff. Sexual is the most common and the cheapest, but there’s tons more to talk about, but that’s the basics. If you’re gardening, always check your seed packet in case you need to imbibe, scarify, or stratify your seeds.
Chris: It’s like the opposite of the human world where the sexual reproduction is the wild stuff.
Hallie: No, dad. If we asexually propagate humans, that’s the wild stuff.
Chris: Oh, that’s fair. That’s a good point. I never thought about that. How would that look? I don’t think that this podcast is the forum for that kind of speculation, but now I’m curious. I mean, cloning, I guess.
Hallie: That’s exactly cloning. Precisely, exactly. Yes.
Chris: Wait, is asexual propagation in plants cloning?
Chris: All right. Well, you know where things get really wild?
Chris: In the break.
Hallie: Hey, let’s go.
Hallie: I have some excellent news. I would like to very much thank a very new brand new starfruit patron, Patrick.
Chris: Hello, Patrick.
Hallie: Welcome to our wonderful podcast family.
Chris: Welcome. We are so happy to have you along with starfruit patrons, Vikram, Lindsay, Mama Casey and Shianne.
Hallie: Thank you guys so much for all of your support. If you would like to talk with us, our amazing starfruit patrons, all of the rest of the One to Grow On community, you can jump in our Discord group or our Facebook group where we are posting lots of memes and jokes and plant facts and plant questions. So many plant questions.
Lots of houseplant support, gardening support, plant ID, all these wonderful things you can find. You can either go to onetogrowonpod.com/discord for the Discord group or onetogrowonpod.com/group for the Facebook group.
Chris: Facts, fun, memes like dandelions.
Hallie: Yes, come join us. We would love to talk with you.
Chris: Also in March, we’re going to do things a little differently.
Hallie: March is national agriculture month here in the US and we are partnering up with three amazing food and farming podcasts to bring you a little bit of different content. We’re going to be airing some of their episodes so you can learn more about their shows and how amazing they are. We’re going to be talking about this a lot on social media, so you can connect to other very cool people online who are talking about agriculture and food in very fun and interesting ways and doing amazing stuff. We’re focusing on indie producers, so it’s going to be a lot of people who this is their passion, just like me and dad. They really are trying to bring the very best stuff. You can look forward to that. The next episode is technically just at the end of February, but that is when we will start and then the two episodes in March will also be part of this. Until April though, if you want to connect with us, we’re going to be on social media and we’re going to be on our Discord and Facebook, so come join us at onetogrowonpod.com/discord or slash group for the Discord and Facebook group, respectively.
Chris: In April, we’ll be back on the air. But now it’s back to the episode.
Hallie: Dad, do you have a nature of fact for us?
Chris: I do. All right. The past few weeks I’ve been obsessed with this new video, which is not plant related, but it is nature related. It’s about the sun.
Hallie: Oh, I love the sun.
Chris: I love the sun too. I guess it is plant related because we can’t have plants without the sun.
Hallie: It’s everything related. We couldn’t have anything without the sun.
Chris: That’s true. But the Daniel K. Inouye Solar Telescope from the national observatory produced the highest resolution video and photos of the sun ever. The video is mesmerizing and you’ve got to check it out. We’ll have a link in the show notes, if you haven’t seen it already. It’s just about a 15 second video of what looks sort of like this hot boiling gas and each of these little boiling blobs on the video is about the size of Texas. They’re massive. Well, the sun is massive and each of these little cells is massive. We see this big white dot in the sky.
Chris: This is just sort of this close up, detailed movement of this plasma gas and fire out here on this giant ball of fire in space. It’s amazing.
Hallie: That sounds so cool.
Chris: It’s really cool. We’ll have a link in the show notes if you haven’t checked it out. We’re glad that you’re here and excited about agriculture. Be excited about space too. Space is cool.
Hallie: Spaces is so cool.
Chris: All right.
Hallie: Tara tarata ta! Nature fact!
Chris: Asexual reproduction. Production without sex.
Hallie: Oh, yes. Exactly or as you put it earlier cloning. This happens naturally in nature, which is where we got the idea to do it.
Chris: Real quick, the banana is a clone. All bananas are clones of one another. Is that something we did or is that something that the banana did itself?
Hallie: Bananas do do that. We basically selected for the banana we wanted and then propagated that a lot.
Chris: Got it.
Hallie: But bananas also do do that.
Chris: Sorry, still reading my book. I got to know.
Hallie: Examples of natural occurrences of asexual propagation includes things like tubers, rhizomes, bulbs, corms, tuberous roots, keikis.
Chris: That’s a lot of words. I feel like I know what a tuber is.
Chris: That’s a potato.
Hallie: Exactly, that is a potato.
Chris: I feel like I know what a root is, a part of a plant. I don’t know why it’s in this example, but you also said corm, which is not corn.
Hallie: No, corms.
Hallie: Rhizomes and bulbs.
Chris: I have a friend named Keiki.
Chris: I don’t know what it is here. We talked about rhizomes once.
Hallie: Which is?
Chris: It’s a kind of root sort of.
Hallie: Modified stem tissue.
Chris: I almost said modified group, modified stem tissue, but it’s usually underground, right? It shoots out and new things sprout out of it.
Hallie: It’s either right below or right on top of the ground. It’s like what grass has. That’s rhizomes. Bulbs example is like onions, irises, garlic. Those are bulbs.
Chris: Your grandmother used to get bulbs all the time and grow them, tulips.
Hallie: Corms are very similar to bulbs. We’ll just say that basically they’re the same as bulbs. Tubers roots, tubers, meaning akin to a tuber. They’re slightly different because technically they’re root tissue, whereas tubers are stem tissue. But other than that, they’re very similar.
Chris: Like bubotubers. I don’t know. Harry Potter reference, anyway.
Hallie: Do you know how we propagate potatoes?
Chris: We put them under the sink until they sprout little leaves on them.
Hallie: Basically, yeah.
Chris: Wait, really?
Hallie: Well, kind of, but not really. On potatoes, you have the little eyes, which is where if you leave them out for too long, they’ll start to grow. You can just take like a sharp knife and cut those eyes out and you leave them for a bit of time. Sometimes you put some sulfur powder on them and then you plant them and they grow.
Chris: That sounds so violent.
Chris: You cut their eyes out.
Hallie: You cut their eyes out.
Chris: You cut their eyes out then you put some sulfur on them and then they grow. Is it pure sulfur or is it a mineral like a salt?
Hallie: It’s like a mineral salt yeah. You don’t always put it on there depending on how wet it is. The sulfur can help prevent bacterial infections if it gets really wet, but it’s not always necessary. You also do have things like keikis. Keiki is specifically a term for orchids, but it’s basically what we call an adventitious root. We have it on other things too. Have you ever seen like a spider plant? Do you know what a spider plant is?
Chris: You have said so many things that I just don’t know about. I’ve seen an orchid. I did not know they were clones of each other.
Hallie: Well, they’re not always. They do have flowers and so they can grow seeds.
Chris: I know you said something that sounded like advantageous.
Hallie: Adventitious roots. Have you seen a spider plant before? Do you know a spider plant?
Chris: I don’t remember.
Hallie: Spider plants have these long thin leaves, but they also shoot out little babies. They’re very common.
Chris: They’ve got little leaves. A little baby is flying out.
Hallie: Pretty much. They’re a very common houseplant. If you Google a picture of them, you’ve got to have seen them somewhere, but they are a very common plant that is very obvious. They have adventitious root tissue. Basically, you have above ground plant stuff and they start to grow roots in hopes that they will take root somewhere.
Chris: The tissue that’s above the ground grows the roots and hopes that the roots will find the ground again. That is adventitious.
Hallie: For the spider plants, how they do this is you have a one big, main plant and sometimes they will flower and grow seed, but they prefer to grow colonially so they’ll shoot out these little babies and these little stands that go like, boom! It’s still attached to the plant, but on the top part of the babies are leaves. Then on the bottom there’s a little bit of root tissue.
If you shoot the baby out and it lands on the ground, it starts to grow on its own.
Hallie: That’s what adventitious root tissue is. When we are propagating plants for our uses, oftentimes we will take cuttings. A good example of this is the potatoes, like we were talking about. You just cut them up and you’re basically separating them and creating a new plant from a smaller part of a plant. But we can also create plants from cuttings by inducing root growth. The same way that it happens naturally with these keikis and these spider plants. We can take a cutting of something like a pothus ivy and then induce root growth. You did that remember with Jerry?
Chris: Yes, I took the leaf. I believe you said it was above the nodule.
Hallie: Node. You took I think it was two nodes of pothus plant.
Chris: I put that in water. How did that induce because I didn’t do anything?
Chris: When you say induce root growth that makes me think that I should be doing something.
Hallie: Oftentimes, that is how it works. Pothus ivy is just very happy to just do whatever.
They just kind of do their own thing. With many plants, you have to add some kind of hormone. There are five major hormones that plants have. One of them is called oxygen and oxygen controls root growth. If you take a piece of a plant and you put a little oxygen on there, then it’s more likely to grow some roots for you because you’re kind of signaling with these hormones like, hey, here’s the place for the roots.
Chris: Does the oxygen have yolks?
Hallie: Oh my God!
Hallie: That was the worst joke you’ve ever made.
Chris: You said oxen. I thought about, babe, the blue ox out, plowing the field because you also said induce root growth and it made me think of Pitocin for inducing labor. But I guess in the broadest sense, the concept is not dissimilar.
Hallie: I guess in the very broadest of senses.
Chris: You’re giving some sort of hope hormone to get things going.
Hallie: That’s very true.
If you would like to do cutting at home of any plants, we advise that you use a sharp knife. We meaning like the larger plant community I guess. You want to use a sharp knife because one, it’s safer for you. Two, you’re less likely to have any issues with bacterial infection or fungal infection or something like that if your plant is less wounded if you get a nice sharp cut. It’s very similar to people. If you use a rusty old knife to do a surgery, it’s not going to be as good as if you have a clean sharp knife so you want a clean, sharp knife. You want to cut the base of your cutting at 45 degrees. This maximizes the area of exposed stem tissue on the inside gooey bits that touch rooting hormone. If you cut at 45 degrees, you have more surface area than if you cut it straight across so you get more rooting hormone contact. You also give it more room to build up starches and build up what we call callus tissue, which is the most dramatic. Meaning able to differentiate into other plant organs.
Chris: Got to maximize the gooey parts.
Hallie: Maximize gooey parts by cutting it 45 degrees for many reasons.
Hallie: You can cut many different things. You can also layer.
Chris: What do you mean?
Hallie: Layering is also kind of like the spider plant. Here’s what you do. Imagine this.
Imagine you have a bush. You can picture it?
Hallie: You have a bush. You take one of the stems. About midway up the stem, you take all the leaves off for like a two inch section. You take the stem, you pull it down to the ground and you bury that part that you took the leaves off of under the ground.
Chris: You don’t break the stem off. You just kind of bend it down.
Hallie: Bury it and then you let it grow for like two months. Then you cut it off and it’s got the roots on it.
Chris: The parts where the leaves come out turn into parts where the roots come out, I guess.
Hallie: You can put oxygen on that part when you bend it down and put it under the ground to tell them this is the roots area now.
Chris: Yolk docksin.
Hallie: Oh my God.
Chris: Then you cut the top of the stem off and then that sticks up and becomes a new bush.
Hallie: It’s like a whole separate plant.
Chris: Wow! That’s amazing.
Hallie: It’s very cool. You can also do air layering, which is where if you have a tree you cut into the tree to wound it and then you put a little oxygen on there and then you put some potting soil that is damp on it and then just wrap it in saran wrap and wait a couple of weeks. Then you can just cut the whole branch off.
Chris: Just to be clear, this only works with plants.
Hallie: It would not work with people.
Chris: Right. Can’t. Never mind.
Hallie: That’s layering. It’s very similar to cutting except for the plant stays attached until the end of the process. The last step is cutting it off. We used to do have micropropagation.
Chris: Oh boys. Like microgreens only with propagation not greens?
Hallie: It’s wild. Basically, this is in a very controlled, clean room situation. You’re in like a lab.
Chris: Not the wild kind of wild, but the crazy kind of wild.
Hallie: Like the crazy kind of wild where it’s just like wild. It’s like buck wild. You take a very, very small part of a plant. It can be leaf tissue. It can be stem tissue. It’s not usually root tissue because it’s harder to get leaves to grow from roots than it is to get roots to grow from leaves and you have to have both parts to get a whole plant. Basically, you take a very small amount of it. Probably, if you were to imagine if you did a hole puncher on a leaf, like that amount.
Chris: Wow. Just a tiny bit of plant tissue.
Hallie: A small bit of plant tissue and you basically put it in a grow room and it grows a whole new plant.
Chris: You don’t have to do anything to it?
Hallie: You do. You put it in algae and the algae usually has some oxygen. It’s basically like in a little Petri dish. Then once it’s grown up a little bit where it’s big enough where you’re able to pull it out, then you can pull it out and put it in some potting soil. Then you put that in a grow room with lights and water.
Chris: I feel like the oxygen would have to be really tiny to fit in the Petri dish.
Hallie: No, this is not a good joke.
Hallie: I’m not engaging with this.
Chris: All right. You take a hole punch, punch a hole in a leaf. You put the little piece of plant confetti in the Petri dish and you make a new plant from it. That is pretty wild.
Hallie: It’s buck wild. It’s very cool. We do it a lot for science. Sometimes we do it for woody plants where you have a very high market value because it’s expensive to have grow rooms and stuff like that. You also need much more specialized labor. You could probably layer a bush. You understand the process. You could go out berry part of a branch and get any plant. But to work in a lab and to really handle those chemicals, it’s a lot of infrastructure. You need specialized labor. It’s very expensive. We do it for science. We do it for things that are more expensive so that you can afford to spend more, to get like really clean, good plants.
Chris: I have two thoughts. One is this means in that tiny bit of plant, there’s enough information for an entire new plant.
Hallie: Yes, there’s a concept for that actually it’s called total potency. It’s the idea that from one cell you could grow a whole plant.
Chris: That’s an amazing term. That plant has got total potency. That’s awesome. From one cell.
Hallie: That’s the concept.
Chris: My other thought is I assume it has, but has this not worked for the American chestnut?
Hallie: No, the problem with the American chestnut is not that we can’t grow more chestnut trees. It’s that if we do grow more Chestnut trees, then there is fungus that will then still get to them. It’s more an issue of breeding with the chestnuts than just growing more of them. This fungal blight is just so ubiquitous. We’re having a hard time getting resistance into the actual species.
Chris: Got it. Real cool. Now we know how to make new plants.
Hallie: Do you feel educated?
Chris: I do feel educated.
Hallie: Do you feel like you should have taken a whole semester to learn all of this?
Chris: I don’t know. Melissa, let us know what you think. I bet you knew all of this stuff already and I bet everyone in plant propagation this semester can listen to this episode and get A’s.
Hallie: Maybe so.
Chris: All right.
Hallie: Knock, knock.
Chris: Who’s there?
Hallie: Petri dish.
Chris: Petri dish who?
Hallie: There’s oxygen in your Petri dish.
Chris: You said mine was a bad joke?
Hallie: I’ll leave the jokes to you. Fine.
Hallie: It was off the cuff, okay?
Chris: So were mine.
Chris: Thanks for listening to this episode of One to Grow On.
Hallie: This show is hosted by me, Hallie Casey and Chris Casey.
Chris: It is produced by Catherine Arjet and Hallie Casey.
Hallie: Our music is Something Elated by Broke For Free.
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Hallie: You can find all of our episodes as well as more information about the show and the team on our website, onetogrowonpod.com.
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Chris: Be sure to check out the next episode in two weeks.
Hallie: But until then, keep on growing.
Chris: Bye everybody.