collectible houseplants, with darryl cheng

SOME PEOPLE collect art, and others collect vintage cars or maybe stamps or coins. Darryl Cheng collects houseplants. And in his latest book, “The New Plant Collector,” Darryl suggests some gorgeous possibilities with detailed guidelines for figuring out how to make a good match for your growing conditions before you invest.

Ready to add some houseplants? Darryl, better known as @HousePlantJournal on Instagram, uses all the technical insights available to him to make the countless houseplants that share his Toronto home thrive. He’s the author of a previous book, “The New Plant Parent,” and creates the popular website, houseplantjournal.com.

Plus: Comment in the box near the bottom of the page for a chance to win a copy of the new book, “The New Plant Collector” (affliate link).

Read along as you listen to the March 11, 2024 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on Apple Podcasts (iTunes) or Spotify (and browse my archive of podcasts here).

collectible houseplants, with darryl cheng

Margaret Roach: You’re so busy all the time; you’re so productive. Another book.

Darryl Cheng: Yes. Yes. Very exciting.

Margaret: Yeah. And I’ve been reading the new book; it’s very enjoyable. And of course, now I want all the plants, but that’s another problem altogether.

Darryl: Yes.

Margaret: A couple of years ago, when your first book came out, we did a podcast together about your approach to matching each kind of plant with the right light conditions for its peak performance. And I see on Instagram you’re still at it, you have your light meter in hand a lot of times. You don’t go by a casual assessment of the conditions, but you really go by data and making solid matchups as I said in the introduction. So, just for those who may not know your approach, just give us your brief version of your thinking on light, and why you have that light meter a lot of times at the ready [laughter].

Darryl: Yeah. I mean, my background is engineering, so I sometimes call my blog an engineer’s approach to houseplant care. And so, if we just really just plain look at a plant as a kind of machine, it is really just a solar-powered sugar factory. And those little sugars are what gives sustenance to the plant. So when I approach how should I take care of a plant, really the first thing I consider is light.

And when I started using a light meter, before making my own, I realized that light levels varied dramatically based mostly on the size of your window or how close you put a plant to the window. And yet, most plant-care advice, houseplant-care advice in particular, never really addressed that critical difference between potential light levels so much as at least the way I did in my first book, and for sure the way I do in my second book.

Margaret: Yes. And it is a measurable thing. In other disciplines, light is something that is… Think of photography, for example [laughter]. I mean, it is something that is measured. So, you’ve availed yourself of that kind of knowledge, and it’s fascinating. So speaking of light, there’s been so many technical advancements, it seems like, in recent years in the products to help us light our plant-growing areas better.

I think I read about it on your website, I see these LED grow-light bulbs now that almost look like an old-style light bulb that you screw into a socket. It yields 150 watts of light, but only uses 12 watts of power, it’s an LED, it’s like maybe 20-something dollars. It’s not a fortune, and it’s not emitting a lot of heat and it’s not 7 pounds or something. You know what I mean? It’s really a lot of progress, isn’t there?

Darryl: For sure, for sure. And actually, technologically speaking, I would say we live in a golden age as a houseplant owner, because think 20 years ago before we had readily available white LEDs, the only LEDs were those kinds of weird purple-colored kind, and they were also very expensive. And so, today, as a casual owner of houseplants, if I wanted to keep, let’s say, a cabinet full of plants, but away from a window, those white LEDs, you can buy a 2-foot-long one, something that can fit inside the cabinet. And these light fixtures, the ballasts are not like the old days of fluorescents, which are really heavy and need lots of electrical work, but these guys can just stick at the top of a cabinet very easily.

And so, it gives a lot more opportunities for collectors like me to own these tropical plants that also they don’t have such high light requirements compared to… Well, I don’t know where we’re airing this podcast, but let’s say growing tomatoes in your basement [laughter]. Requirements are not nearly as high as for that kind of growing. So, it is kind of a golden age, especially now that we have white LEDs that are cheap and readily available.

Margaret: Yes. In the new book, you begin by offering us some guidelines for collecting plants should we decide to surrender [laughter]. And you call your guidelines, they’re “your ABCs of houseplant appreciation,” because a lot of plant possibilities out there, but we definitely need a way to filter intelligently. So, what are the ABCs?

Darryl: Sure. Yeah. So, the ABCs are A for aesthetics, so you can appreciate how a plant looks, right? Its beauty, the structure. Then there’s B for biology, and that is just appreciating how the plant grows, the way it sends out new leaves, maybe if it flowers, or even as you propagate, the way that it continues growing after you cut it back.

And C is  companionship. And that is quite simply that you can have a sentimental attachment to your plants. The example I always say is I have a particular rabbit’s foot fern that I really like. But if you just took it away and replaced it with the identical type of plant, it wouldn’t have the same meaning to me, because it’s not the one that I grew.

Margaret: Right. I have my grandmother’s Clivia. I mean, even if someone gave me a different Clivia… I saw that you got one in the fall, or last year sometime.

Darryl: Yes, yes. And I mean, it wasn’t from my grandmother, however, it was from a garden-club sale. So my local garden club, they always have plant sales. So then, when I saw the Clivia there, I knew I had to get one because I heard about how much this plant is often passed down in generations and how it’s just so prolific.

Margaret: Yes, it is. I suspect mine is 80-plus years old. It’s now many plants, it’s many, many plants. And that’s not an unusual story. I’ve met many other people who have ones that are old ones, but now it’s many large plants, not just one plant.

And speaking of companionship, and you just alluded to it speaking about purchasing yours at a garden club, there’s the Begonia Society or the Gesneriad Society, or the Orchid Society. One can also have human companionship, and make new acquaintances and get new knowledge through plants, through sharing plants, and going to plant events and so forth. So that’s kind of fun, too, whether we do that virtually or in person. Yeah.

Darryl: Yeah. For sure. And I also think I would hope that maybe because of in social media now that it’s very common to have like a plant account, that that has maybe given a resurgence to plant societies, because that’s the in-person version of plant clubs or online kind of thing.

Margaret: Yes. You make a good point in the book that in all things collectible, whether it’s antiques or whatever it is, the word “rare” is an interesting word [laughter]. It’s used to describe a collectible. And what it usually is, is a neon light flashing that says, “Expensive, expensive, expensive. We’re going to make you pay for this.” But it can mean a couple of things for plant collectors, yes?

Darryl: Yes. And in the book I try to make a good point, which is not my own idea, it’s actually from Mike Rimland from Costa Farms. He stated that there’s two different concepts of rare—for a plant, I mean. The first is rare just on the Earth, right? And so, these are the kinds of plants you really don’t want to be collecting in your home. You’ve got to leave that to professional conservationists, botanists and those kinds of things. It’s not something you want to have in your house.

But then there’s just rare in cultivation, in commercial cultivation. And that just means that maybe the plant is not widely cultivated, or it’s maybe very slow in the way that it’s cultivated, and therefore not a popular plant to grow in a greenhouse, for example. Because every plant that’s grown in a greenhouse requires time and space. And so, if you choose to have one that takes a long time, then it takes away the space from something you could sell faster.

Those are the kinds of plants that I think a lot of people are seeing online with “rare.”And I mean, yes, they are rare and special in the sense that you can’t just buy them at the grocery store. And the fun thing now is that when people realize that specific plants are ones that people really want, then if it happens to be easy to cultivate, then a mass producer will cultivate it, and then hopefully bring the price down and let it be available at your local grocery store.

Margaret: Right. Some plants that we could collect, and you have… I don’t know if it’s the back half or two-thirds of the book, how much of it is kind of almost genus-by-genus of plants you would recommend considering collecting and some of the special ones within that genus. And each one starts with an introduction, but then there’s almost like a chart that says, “This is what its needs are. This is what this particular kind of plant’s needs are.” And you speak about the light and the other things that it needs so that, again, we can make a good match and be realistic before we go out and acquire things that we then can’t make happy and have a disaster on our hands.

Darryl: [Laughter.] Exactly. Yes.

Margaret: Yeah. I think begonias are a great way to get into plant collecting. They look… Well, we used to call them fancy-leaf begonias. They look fancy, they are showy, they’re distinctive. There’s so much going on with just the foliage. And yet, they’re not always… There’s plenty that aren’t super-expensive and rare [laughter]. You can still get a great, beautiful assortment. You have one picture in the book, I think, that has a display of them on a table, and it’s gorgeous [photo, top of page]. It’s nicer than any floral arrangement to have a group of begonias altogether.

Darryl: Oh, yes. For sure.

Margaret: If I want to become a begonia collector, what kind of a home should I give them? Are they demanding light-wise? What’s their sort of profile?

Darryl: In particular in the begonia section, this section is a little longer because, in fact, a lot of my learnings of begonias comes from, as you mentioned, begonia societies. They have whole societies based just on the Begonia genus. And so, there are specific, I guess you could say, classes of begonias. But in the book I only talk about two main ones, which are the cane types and then the rhizomatous types. I split that up in the book. And as you mentioned, for all the chapters, the section that talks about their care, I think the important thing to note about how I describe the care is that I try and make it more parameterized.

What I mean is that for every environmental condition that I mentioned, it’s something measurable and concrete that you can actually assess for yourself in your own space. And even within the light section, for example, of the light in the environment section, I break it up into three categories or, I guess, contexts of lighting that you might have. So, if you’re doing it natural light through a window in your room, then I give some parameters for that. And if you’re going to do purely grow lights, I give another parameter for that, namely the parameters you need to actually achieve the same light level that I’m suggesting.

So, you need to measure it at the leaf and then keep the grow light on for 12 hours, let’s say. And basically, the point is then when you read this section, I would hope that it’s not vague or just giving you some broadly defined thing like “bright indirect light” and that you put your plant where you think it’s bright indirect light, but then you’d start… I would say, “If you’ve actually measured it, is it actually over 200 foot candles in most of the day or not?” But rather than give you a vague thing, I say it directly, “200 foot candles minimum.”

Margaret: Or else [laughter].

Darryl: Or else the plant will not do well.

Margaret: And you have a great chart, I think, on your website as well, that for a lot of kinds of plants gives some of the numbers and so forth. I mean, besides in the book, I feel like isn’t there a reference on your website as well? Yeah.

Darryl: Exactly. Yeah. In fact, I think if you just Google “bright indirect light requirements by plant,” my website will be somewhere. I mean, it used to be first all the time, but it’s somewhere there.

Margaret: That’s very helpful. It’s just very important for us to not just go shopping and go, “ooh,” and “ahh,” and grab at the pretty faces. But to say, “Hey, can I make a home for this plant?”

Darryl: That’s right. Yeah.

Margaret: I was going to say, I think begonias are a great thing to collect because I think our money… Obviously, there’s some very unusual ones that are rare and expensive and so forth. But compared to, say, the Monstera, the Swiss cheese plant, which have become a thing—and we’re talking a really serious investment in many cases because they become so collectible—I feel like you can still get into begonias and have a gorgeous collection without mortgaging your house or whatever.

Darryl: Yes, for sure. Yeah.

Margaret: The Monsteras, on the other hand, I was interested if you explain about the… Speaking of light, that you observe some varieties… They’re called “Swiss cheese” plants, so holes in the leaves or lacy leaves, or however we want to describe it. And that some are more inclined toward more of that openness in the leaf shape according to how much light they get as well. Is that correct?

Darryl: Yes, yes. I mean, I didn’t do a rigorous A-B test experiment, but I did do one very clear case example where I took the pup from a Monstera. When I say pup, I mean the very, very tiny little growth that comes off the side of a Monstera that has very small, heart-shaped leaves, so solid leaves. I took that off, potted it by itself, and then stuck it under a grow light where I would measure 1,000-foot candles, and it was on for 12 to 14 hours a day. And in that condition, by the time that little plant put out its fifth leaf, that fifth leaf already had a full set of fenestrations, like cuts on the sides, and then even some mid-rib fenestrations. [Darryl with a Monstera, above.]

Margaret: And that’s what they’re technically called, it’s fenestrations. It’s like positive and negative. Again, that’s why they call it the Swiss cheese plant.

Darryl: Right, right. Yeah. Fenestration, I guess, comes from fenetre, the French word for window. They’re talking about basically any holes or cuts on the leaf that makes it look like Swiss cheese.

Margaret: Right. We could spend some serious money here, or we could get a more basic one. But what I found fascinating also was in that section of the book, and I think it may have appeared in some other places as well, you talked about a gadget that I really didn’t know about, which is these moss poles. I’ve seen them, the old-style ones where someone in a greenhouse situation made a device to make a plant go vertical, but I didn’t… Now they’re a product even, aren’t they? So tell me about moss poles, because those come up in the book, and you train some plants that way.

Darryl: I think at the nursery, prior to the craze of people getting really into houseplants, the moss poles that were available at nurseries were simply long-fiber cocoa coir that was wrapped around a post. And if you were trying to grow, let’s say, a Pothos or a Monstera, up that type of moss pole, it’s actually very difficult to get the plant to root against it, because the coir doesn’t really hold onto much water. And of course, the inside of the post is hollow.

When I’m talking about the moss poles that I’m referring to in the book, and the way that a lot of my friends online, let’s say, have grown their really, really large Pothos, it’s actually a sphagnum moss filled inside a structure, like a plastic structure, and one side of it is a little bit open, let’s say, with a mesh of some kind. And that allows the vine to root into the sphagnum moss because, of course, sphagnum moss is like a sponge, so it’s easily moistened and stays moist. [A detail of the moss-filled pole; Darryl uses rubber clips to help the plants get achored on the moist medium.]

Margaret: So you made these. It almost looks like coated hardware cloth that’s painted or whatever. You made this pole and you stuffed it with the moss and then let the plant…

Darryl: Yeah. Yeah.

Margaret: Because that’s what I didn’t know, is if there was actually a commercial product now like the one you showed in the book, because I see there’s all the other ones that, as you say, are more solid. But I didn’t know if the kind that you recommend are also available, or if it’s a DIY kind of thing.

Darryl: So, there are several people who sell just the plastic outer part. You buy it and then it’s already precut and everything, and you just wrap it in, maybe fix it together with some zip ties. Yeah. So, there are products out there for people who want to grow like this. Because the reason why people want to grow an Aroid type plant up a moss pole is because then its leaves develop into the mature state much faster.

Margaret: Right. Well, it looked gorgeous, and you had a picture in the book almost like a room where there’s different varieties or different species standing next to one another, each one trained up a moss pole, and they’re stunning looking. They’re gorgeous. [Above, pothos and philodendrons trained up moss poles.]

Darryl: And so, that’s the appeal of doing that with your Aroid type plants.

Margaret: Well, I loved it. I adopted a Syngonium last… maybe two summers ago, two springs ago at the garden center. I was doing some mixed containers for the seasonal garden outdoor containers. And they just looked good, and I thought, I’m going to use them as the spiller over the edge of the pots with various other things. And then, at the end of the season, I didn’t have the heart to let them die. I’d never grown one before, but I potted them up and brought them in. And oh my goodness, they’re like a mile long [laughter]. How easy are they to propagate? In the book, you have some gorgeous ones that have pink-splashed leaves and so forth as well [below]. And a lot of nice ones.

Darryl: Yeah, for sure. I think learning propagation as a way of just fundamentally understanding it with your plants and seeing it as a constant thing that you do with a plant then allows you to really enjoy the plant in the longterm. In the book, for certain genus types, I have a kind of diagram. I don’t know if you noticed them, but a kind of circular diagram where the plant starts off in a presentable phase and it grows bigger and it looks even nicer, but eventually maybe it gets a little too gangly and starts to look a little less presentable.

And then I tell you that you should propagate it however it’s supposed to be propagated, whether by stem cutting or leaf cutting. Then for a while, the plant may not look so presentable, but hopefully it’s coming back around to look nice again. That’s the idea to say that yes, your plant may not always look the greatest, especially right after you’ve pruned it off for propagating, but that there’s always a path to get it back to looking presentable again.

Margaret: Yeah. And I was going to say, speaking of things that need to look presentable again, hopefully, hopedully: I’ve grown begonias, rhizomatous and cane begonias, for a million years. But something about this year, it’s just funny. I mean, in the same house, it’s not any different. They summered outside, like they usually do in the same place, blah, blah, blah. Didn’t change anything else. But boy, they really have taken a beating. They are really unhappy this year.

And I think, O.K., I’m going to do—especially with the ones that have the rhizomes that look like caterpillars spilling over the edge of the lip of the pot—I’m definitely going to be doing some serious haircuts, I think. Cutting back into the plants and seeing what happens. But it’s time for that, I think; a little cleanup for those of us who summer our plants outside and then bring them in and they tend to decline a little bit, because I don’t have all the lights you have. I do want to get some of them, though, because I think it’s…

What I was going to ask is: Because you have these supplemental lights and more ideal conditions 12 months of the year, are you feeding year-round? Because I don’t feed in the winter because the conditions are such low-light, relatively speaking. Are you feeding year-round?

Darryl: Yeah. When I talk about fertilizing for houseplants, especially the ones that don’t go outside, that means they could have a growth spurt in the middle of December. Like if I see a bunch of new leaves coming out of the stems, then I know it’s actively growing, and therefore I will be using fertilizer. And I do it such that I actually have the slow-release pellets in the soil, which means every time I water, it releases a little bit of fertilizer in there. And so, therefore, every time I water those plants that have the granules, they are getting fertilized every time I water.

Margaret: O.K. But in the offseason, are you adding it to your watering can as well?

Darryl: For some plants, if I don’t have the granules in them, then I will be putting a liquid fertilizer into the-

Margaret: Because they’re in a high-light situation, or an adequate-light situation; they’re not suffering like some of my poor babies in my [laughter]…

Darryl: Well, yeah. And of course, now that I live in a house, there are… My huge Monstera, for example, is outside in the spring and summer. But then now, it’s in my basement under a rather weak grow light just to keep it alive until winter. And so, for that one, I’m not fertilizing because I don’t expect any growth to come out right now.

Margaret: O.K. Well, Darryl Cheng, I always love talking to you because I just love that you are so thoughtful about, again, making good matchups with your plants and about just being such a good plant parent [laughter]. I think so many of us have learned so much from your work and what you’ve shared on social media and from… I mean, you have everything from a course, to you do consultations by email, and helping people with their sick plants and all kinds of things. And now the new book. So, congratulations on that. And I hope I’ll talk to you again soon.

Darryl: Thank you so much. Yeah, for sure.

(All photos from “The New Pl;ant Collector,” used with permission.)

enter to win a copy of ‘the new plant collector’

I’LL BUY A COPY of “The New Plant Collector” by Darryl Cheng for one lucky reader. All you have to do to enter is answer this question in the comments box below:

Is there a houseplant you lust after (or one you have that is your very favorite)? Tell us.

No answer, or feeling shy? Just say something like “count me in” and I will, but a reply is even better. I’ll pick a random winner after entries close at midnight Tuesday, March 19, 2024. Good luck to all.

(Disclosure: As an Amazon Associate I earn from qualifying purchases.)

prefer the podcast version of the show?

MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 15th year in March 2024. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. Or play the March 11, 2024 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes/Apple Podcasts or Spotify (and browse my archive of podcasts here).