Episode 260: repotting houseplants

Transcript

Episode 260

Jane Perrone
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Jane Perrone
Hello and welcome to On The Ledge podcast, where the re-potting don't stop! But yes, it's re-potting week this week; getting those roots out on display! I'm your host, Jane Perrone, and this is the legendary podcast about houseplants: it's On The Ledge! And as I've already said this week, we're talking about re-potting. It occurred to me recently that I've never done a show devoted to this topic, despite the fact it's so important. Plus, Dr. Scott Zona, botanist extraordinaire, will be here to answer a question about plant lifespans. If you follow my instagram - @j.l.perrone - you'll know that I have received my author copies of Legends of the Leaf. It exists! It's in the world! I'm going to sign 600, yes, 600 copies very soon, in the next couple of weeks, and so that means books will be making their way out into the world as well. Plus, if you've pledged for the book, you should have received an email offering you the e-book download, so you can read the book right now. If you've ordered the print edition as well, you can, of course, hold off and keep the suspense going, but if you want to dive right in, right now, to Legends of the Leaf and you've made a pledge, you will have that e-book download in your inbox, so check it out! Let me know what you think! This week's Legends of the Leaf fact for you concerns the Peace Lily. Now, I don't know if you've ever thought about this plant in the wild, but Spathiphyllum Wallisii, when it's growing wild in Colombia, like most plants has various creatures that will feed on it and one of them is the Amber Phantom butterfly. This is a beautiful-looking butterfly, with transparent wings, an orangey glow and these incredible eyes which help to camouflage its form from predators - and just to be clear, I'm not talking about its actual eyes, I'm talking about eye-shaped patterns on its wings here - and it lays its eggs on Spathiphyllum Wallisii and then these horny-headed caterpillars feed on the leaves. So, if you ever get to see Spathiphyllum Wallisii in the wild, look out for the Amber Phantom butterfly. It's not one that likes to be in the sun. Funnily enough, it likes to skulk in the shadows, especially at dusk, and feeds on rotting fruit on the forest floor. Do go and have a look, if you can, at a picture of one of these beautiful butterflies. I think it'll light up your imagination! So that's this week's Legends of the Leaf fact! I will be running a Legends of the Leaf giveaway next month, for a number of copies of the book. I'm not exactly sure how many, probably five. That will be open to anyone around the world and will include some On the Ledge stickers and a few other bits and bobs, so look out for that if you want to get your hands on a free copy! And the Sowalong continues apace. Thank you to everyone who's been using the hashtag otlsowalong on their social media posts. Planty Teacher is growing various vegetables and also some Bonsai, and Botaniqueer has been celebrating some Gonialoe variegata plants that were grown 57 months ago. Wow! They're looking good and it just shows you what you can do when you grow plants from seed. Kev's Orchids has got Sinningia calcaria seedlings, which are looking nice. That's a lot of seedlings there Kev! I hope you've got lots of pots for pricking out, when the time comes! One of my Patreon subscribers, Lisa, has sown seeds from an Amaryllis seed pod, and out of 40 or 50, nearly all have germinated, so that's a pretty good result! Now Lisa wants to know what is the most likely way this plant got pollinated, since it was indoors and Lisa didn't knowingly pollinate the plant. So could it be an errant-insect-from-outdoors self-pollination? Well, I had to go and look up Hippeastrum - as Amaryllis are more correctly, botanically known - pollination and find out how this goes about. Now, the answer is that Hippeastrums can pollinate themselves. It does happen. So that may have happened in this case, particularly if there was some insects around. I suspect the pollen may have easily transferred from one sexual organ to another on the plant. You can use a paintbrush and move pollen from one flower to another if you do want to deliberately cross pollinate, but it's quite possible that you have got a self-pollinated plant here. So it's just a question of time, to see what happens with those seeds and what you get. You might get a very different scenario and this is the joy of sexual reproduction, that you do get a whole host of different results from one sowing, often, so let me know, Lisa, how this goes. I suspect that you're gonna get loads of nice plants, but it may take a couple of years for them to get up to flowering size. Patience is all. This is often the case with houseplants. And over on the Facebook group, Houseplant Fans of On The Ledge, Andy has found that his Dioscorea Mexicana seeds planted in February have come up, and, oh my gosh, are they adorable! They are so cute! They are extremely heart-shaped, if you can imagine that, and they're tiny but perfect. I love these! Well done, Andy! Marcel has been growing Daliah seeds, which have come up. I've never grown Dahlias from seeds but that's looks great! And Alex's papaya babies are also looking amazing, sown in January. Wow, they look so fresh and good. Really impressive, Alex, well done! And then finally, Heidi has sandpapered, soaked and sown Lupin seed. Now, yeah, I've never sown Lupins. I have to say there's something about Lupins that gives me the willies! Does anyone know what I mean? I think they're very beautiful, but something about them just makes me come over a little bit peculiar, but I love this, that you've managed to do so much research that you found out the best way to sow, Heidi, and, indeed, some seeds do need to be nicked, or sandpapered. Some people just put them in their pocket to rub around for a little bit, to aid germination. So that's an interesting one. So keep sharing your On The Ledge Sowalong stuff. I'm hoping to bring you some more episodes with a seedy theme coming up, and it's fantastic to see all your great progress, so do keep posting that in Houseplant Fans of On The Ledge and also on Instagram, #otlsowalong.

Jane Perrone
Now it's time to talk re-potting and I want to talk first about how to know whether to re-pot because I think this is one of these topics where sometimes people get on a regular routine and they just think, "Oh, it's spring, I've got to re-pot" and then other people wait 'til it's a little bit late, the plant's already stressed because it's run out of room. And, if we can, we want to try to re-pot just before that point, just when the plant reaches the end of its tether, as it were, in terms of space in the pot and nutrients and substrate quality, and get that plant upgraded to a new pot or, indeed, not necessarily upgraded, maybe just trimming the roots and putting it back into the same pot is a good way forward for some plants at some times. So, how do you spot your plant looking a little bit miserable? Well, I'm just gonna go and get a couple of plants from the house so I can give you an idea of what we're talking about with a real example, which I always think is valuable. So hang on a minute, I'm just gonna pop and get some plants. Right, I'm back, and let's have a look at what we're dealing with here. I've brought three plants out to the office, which may or may not need a re-pot. I've got a Sinningia. I think it's Sinningia reitzii, although I haven't got a firm ID on it, I've got to wait for it to flower; a young Beaucarnea recurvata, the ponytail palm, and my lovely Hoya polyneura. So, where should we start? I think we'll start with the reitzii. This is a caudiciform plant that I grew from seed: #otlsowalong! The reason why I want to check this plant is because it's in a very small and, indeed, miserable pot that's got a big crack down the side of it. I have no idea what's going on under the surface. I can see it's throwing out new growth. Because it's a caudiciform, I don't necessarily want to over-pot it, but I'm also aware that this plant has been in the same pot for, gosh, probably three years, and the caudex, the fat base of the plant, is about half a centimetre smaller than the pot itself, so I'm thinking this may be time for a re-pot. There's only one way to find out and that's to have a look. The other thing that I'm noticing about this plant, is it's had a bit of growth die-back and I'm wondering whether that may be also related to a lack of space in the pot. So let's have a look and see what we can see with this one. I'm just going to roll back a bit. I've got my trusty plastic bowl to have a look at this plant, so without making too much mess. Now, when you're taking your plant out of its pot, if it's in a plastic pot, I tend to take this approach where I have a little bit of a massage of the pot before I even attempt to take anything out. Oftentimes, plants can get stuck to the side of pots, not so much with plastic as with terracotta, but it's worth giving the pot a bit of a massage and then you can see what's going on as you try to pull it out, and this one's come out absolutely in one lump. Now that's probably the first sign that it may be rootbound. And I'm looking underneath, this plant has got quite a fibrous, fine and fibrous root ball, so I'm not seeing any massive roots on the outside, but I can see there is a lot of root material holding this compost together and it also feels very dry and I'm wondering whether the plant is not putting on as much growth as it might because the soil has become, basically, hydrophobic, and I'm thinking this is telling me that it's time to give this plant a small upgrade from this cracked pot that I've got here, so that the plant maybe has a centimetre and a half / two centimetres around the edge of the caudex, between the caudex and the side of the pot. So not a massive upgrade, but just a little bit more room for growth. And I'm also going to think about maybe getting a very fine knitting needle and just very carefully, ensuring not to pierce the caudex, just putting some holes into that rootball, just to encourage air circulation. So that's probably number one. Plus number two is the Beaucarnea. Now, this one, this is a re-pot that I'm doing, not really because the plant needs a new pot, necessarily, but - sorry, it's got caught up under the . . . There we go! - not necessarily because it needs a re-pot, but because it's another caudiciform, and, somehow, this plant has managed to get in a weird position. So, basically, the caudex is lying to one side of the pot and it's at an angle, rather than being nice and upright, and maybe the bottom third being covered with soil, literally, it's sitting on the surface. So this is a plant that I think really does need re-potting. If I look at the bottom of the pot, I can see a little bit of root coming through. I don't think it's probably filled the pot, but I think I just need to give this plant a re-start because if it flops over like that and ends up getting damaged, then it's obviously not going to do the plant any good. So it will probably develop a better root system if it's better positioned in the pot and I can even see that there's some roots here, where it's kind of fallen over, which have been broken off, and so the plant can't grow unless it's got a really good root system. So I think this one needs a re-pot, not necessarily a bigger pot, I just need to give it a bit of a sort-out. So that's what I'm going to work on today, with this one. And it is a gorgeous little caudex, so I'm looking forward to seeing how that turns out. And, generally speaking, when I'm looking at plants that I'm considering for re-potting, one of the things I'm thinking about is also does the plant look generally dull, and not quite on form, in a kind of indefinable way? Oftentimes, that's telling me that it's time for a re-pot. This is what I'm experiencing with this Hoya polyneura. It's just looking a bit dull, and a bit not-quite-with-it! Now, this plant, when I lift it out of the pot, it's in a clear pot, I can see that there are a big bunch of roots coming through the bottom of the pot, but because it's in a clear pot, I can also see that the rootball's not completely taken over, but there are roots coming out at the bottom of the plot. And I can also see that, as I say, the leaves just . . . they're a bit dull, they're not quite as luscious as I would expect them to be. This is a plant that also has an Oxalis planted in the top of it. Deliberate? Probably not! They probably just got in there somehow, these tiny little, I think they're probably corms of Oxalis corymbosa aureo-reticulata, which is the lovely yellow-veined Oxalis, and everything's a bit dried out and sad on this plant, so I just need to give it I think a refreshing a refreshment of its potting mix, and a slightly larger pot. And I think it will also be a good opportunity to give the plant a good wash down as well, check for pests, remove dust and just generally give it an MOT. But that's what I'm looking for, a kind of a dullness to the leaves, or the leaves not feeling as firm as they should do. That's often an indication that it's come time to re-pot. The other thing you might find when you're looking at plants that need re-potting, is that when you water, the water just runs straight through, and this would be the case with both of these caudiciform plants I've got here. Unless I soaked these in a bucket for an hour, I suspect that the water would just run straight through because that soil has become hydrophobic and that just means it's shaking off the water rather than absorbing it, and when it becomes super-dry, this is sometimes what happens, particularly when the compost has kind of slumped down in the pot and there's not enough air spaces left. So look for water running straight through, look for roots coming out the bottom of the pot, and then when you do take the plant out of the pot, you can check what's going on around the root ball. I'll stick a photo in the show notes of a really rootbound plant, to show you how bad this can get. You know you can get to the point where there's no soil visible, particularly on chunky-rooted plants like spider plants - Chlorophytum comosum - and Dracaenas, like Dracaena marginata, and Sansevarias. You end up with just more root than substrate, and at that point, it's really time to take action and get re-potting done. The other symptom that's always a factor with re-potting, is wilting. So, if you see a plant visibly wilt - obviously the classic one for this is the Peace Lily, Spathiphyllum - you know, it wilts and you water it and it wilts very quickly again, just remember wilting can be a sign of water-logging, as well as a plant that's pot-bound, but it's always worth looking, if your plant just keeps wilting, looking at the rootball and checking whether it does need a new lease of life through re-potting. But, like I always say, go ahead and check everything first before you go ahead and re-pot because sometimes plants have got something else wrong and it's not anything to do with the need to re-pot. So we're going to move on to Question of the Week now, but when we come back from that, I will be heading to re-pot these plants and you can come along with me!

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Jane Perrone
Now, Question of the Week this week comes from Sally and it piqued my interest because, like so many planty questions, I really didn't know the answer! Sally wants to know whether plants have a defined lifespan. So what she's referring to here is, assuming a plant doesn't get eaten, or flooded out, or destroyed by a pest, doesn't get destroyed by drought, how long can a plant live and what are the things that determine how long it goes on for? And Sally knows, from a nursing background, that there's something called apoptosis - which I think is a word we should all be using in conversations today! - that is a factor in living organisms - programmed cell death is another term for it - and Sally was wondering whether this was involved in the process of plants reaching the end of their days. So, I didn't know the answer, but luckily enough, I have a number of useful experts on speed-dial, including the wonderful Dr. Scott Zona, who joins me now to talk about this. Scott, this is a good question! I'm hoping that you've got a really interesting answer for this and it's not one of those "We just don't know!" questions!

Scott Zona
No, it's it's a fantastic question and there's actually a lot to unpack in there! So let's talk about something that I think probably most of your listeners, most gardeners, know, is that some plants are annuals, they only live for a year, or less than a year and they do their life-cycle and then they die. Some plants are biennial; they live for two years and then they die. But I think your listener's probably talking about perennial plants, and perennial plants live for many years and reproduce. Most of them reproduce on a yearly basis for many years. And the question of how long can a perennial plant live is a really interesting one. We certainly know of things like the bristlecone pine, in western North America, that lives for thousands of years. I think the oldest living one is not quite 5000 years, but it's 4.8 or something like that. It's almost 5000 years, a single individual! So we know that individual plants can live a long time. There are some studies of other plants in the wild, some palms, for example, that can live for centuries. And in some places, like places like Singapore or Florida, lightning takes out palms and, you know, otherwise they would live for even longer, but they get taken out by lightning strikes. So the question of how long can a plant live? Well, obviously, it varies according to what species we're talking about, but really, plants can live a long time and I don't want to say they're immortal, but, you know, I've had plants, I've had an orchid that I had since I was a teenager, and so, you know, that was, I don't know, thirty, forty years before I finally had to give it up, when I moved north. But yeah, they could live a long time. And barring things like disease and natural disasters and, you know, forgetful owners that forget to water their plants, plants can can live for, you know, many, many decades. And, you know, you hear plants passed on from owner to owner, or from one generation to the next. And then when we get into the question of clonal plants, then it gets really interesting because clonal plants, plants that reproduce asexually through clonal reproduction, through rhizomes, and, you know, producing a new plant, those clones can live even longer than individual plants. So although individual members of the clone may only live for, you know, a few decades, or maybe a few hundred years, the clone itself can go on for thousands of years and so we have examples, again, from western North America, the creosote bush, Larrea tridentata, and sigle felici, down in the southwest deserts, and the largest Larrea clone is thought to be over 11,000 years old! So, yeah, plants could live a long time. Now, your listener also mentioned programmed cell death, or apoptosis, which is a great word. It's a fun word to say! Programmed cell death plays a role in plants just as it does in animals, and probably an example that your listeners will will recognise are the leaves of Monstera deliciosa, you know, the holes and splits in the leaves, that's caused by programmed cell death. As the leaf is developing, you know, when it's very, very, very small, in the bud, parts of the lamina will die and that will result in a leaf, when it's mature and fully expanded, with these holes in it, and that's a pretty unusual case of programmed cell death. In fact, Monstera and its relatives, and, what's the other one? The, it's an aquarium plant, Aponogeton madagascariensis, the one, that really lacy-looking leaf - that also arises through programmed cell death, but that's unusual. The programmed cell death that happens in every plant is what happens in the development of the vascular system. The xylem, which transports water and minerals throughout the plant, xylem cells, individual cells of the xylem, are dead at maturity. They have no cytoplasm. They're just basically empty cells that are connected, sort of like pipes that conduct the water, and they're dead at maturity. And that's because of programmed cell death. So there's an example of programmed cell death that happens in all vascular plants. Whether programmed cell death is involved in the senescence and ultimate death of an individual, like an annual plant, is that programme cell death at the end of its lifespan? Yeah, it gets a little conflated when we're talking about individual cells and then the whole organism, but yeah, it's, I think, certainly, programmed cell death is involved in abscission of leaves and so I suspect it is involved in the death of a whole plant, like an annual plant, at the end of its lifespan.

Jane Perrone
Thank you so much to Scott for answering that question. And Patreon subscribers at the Ledge-end and Superfan level can hear an extended version of our chat, where we get deeper into the subject of plant lifespans, in the latest episode of An Extra Leaf, my bonus podcast for Patreon subscribers. Right, let's head out to the potting shed. It's time for some repotting, using the potting shed for what it was intended for. I've come out to the shed for this potting up. It's been sunny today, so the shed has warmed up nicely. We are at 25 degrees centigrade in here right now, which is great because it means that the potting mixes in here have warmed up to room temperature, so I'm not going to shock any of my plants when I re-pot them. I've got my cup of red bush tea and it's a bit of a mess out here, but I'm just going to work with it. So, the first thing I need to do when I've got my pots that need re-potting, is to make sure that root ball is soaked. So I've got these plants that I talked about earlier, the Beaucarnea, the Sinningia and the Hoya, and I'm just gonna give them a really good soak in some room-temperature water for about half an hour, so let's get going with that.

Jane Perrone
Now I need to just intervene here, to say I did record myself potting up the Sinningia, but it rained so hard that you could hardly hear me! So you'll just have to imagine me re-potting the Sinningia and we'll move straight on to the Beaucarnea! Oh, suddenly the sun's come out! I've had a few slurps of tea and the rain has stopped. Hurrah! That's delightful. So, now I've got this Beaucarnea and I'm going to do before and after shots in the show notes. You can see what it looks like before I sort it out and I suspect with this one, as I say, that we're going to be in a situation where I'm going to end up putting it back into the pot it's already in. So I've got some more potting mix if I need it, but I don't think I will. I'm going to be careful on this one because, as I say, it's a bit precarious on top of the pot. I thought that was a slug in the bottom of the pot there, but it's actually a ball of Leca, so that's good. Right, taking it out of the pot, we're going to have a look and see what the situation is with the roots. This is a real danger time, re-potting, for some plants that have thin, fibrous root systems and you sometimes hear from people that they have potted something on and the plant has suddenly collapsed. It's quite common with the very thin, fibrous-rooted plants, where people just aren't careful enough with that root ball. Things with massive, fat roots like Dracaenas, it's not a problem, but for things where you've got delicate, fibrous root systems - we're thinking also of things like String of Pearls, Curio rowleyanus, you need to be really, really careful. And if you're in doubt, for something that isn't succulent, like, a fern, you can stick the whole pot and plant inside a clear plastic bag, once you've re-potted, just to give the plant a bit of support while you're dealing, or while it's dealing with the shock of re-potting. We just want to make that shock as limited as possible, really. So, on this one, I just want to have a little bit of a removal, there's an excess of potting mix here that does not have roots in it. I just want to see what the roots are doing. The roots all look healthy and fine. If you aren't, if you're re-potting something and you find roots that are sort of wizened and look dead, or look slimy, cut them away because they're not going to help support the plant. With this plant, I can see that it's got a good healthy root system, but it just needs a little bit of sorting out because it was just sitting so oddly in the pot. It had been, it was on a windowsill, I think it had been knocked when the curtain was being opened and closed. So we're going to give this a bit of a reset. Beaucarnea recurvata is very tough and it can survive all kinds of different conditions, but I'm going to give this one some new substrate and I'm going to put in a few of the Leca balls, to add to the perlite and the charcoal that's already in this peat-free potting mix, and I'm gonna use that to re-pot, so, again, I'm going to get a tiny bit of my wool insulation, you could use anything, you could use a bit of kitchen towel, you could use kitchen paper, whatever you call it, you could use a paper coffee filter, you could use a bit of newspaper, you could use literally a leaf, I have, in the past, used, like, a dried leaf from a leathery plant like a Photinia, from the garden. It'll break down. It's not going to cause the plant any problems and it works really well just to, again, this pot's got loads of holes in the bottom, so I don't want the substrate which is, you know, quite, reasonably fine in parts, to fall straight through. So now I'm going to just test out where this root ball's going to have to be in order for the caudex to be kind of half-covered but also central and not on-the-lean, and then I'm just going to put a tiny bit of substrate in, it's always best to kind of do it gradually because it's a pain to have to take substrate out. So I'm now popping the caudex on the top and working out that that's about the right height. I just had a change of thought, I was just wondering if I'm going to put this in terracotta. Actually, I think I'm going to put this in terracotta, just thinking as I'm talking here, the reason being that then I won't need to have a cache pot and, actually, the beautiful caudex can be displayed. So I think I'm going to do that. I happen to have, thankfully, thank goodness I did some cleaning, various really lovely terracotta pots that are empty here, that have been all freshly cleaned with hot soapy water. You can put a dash of bleach in there as well, if you want to be extra secure, but just make sure you rinse them thoroughly in clean water when you've finished. Now, ideally, this terracotta pot should be soaked before I put the plant in here, because then it means that the plant will be well served with moisture in the new pot. However, I'm not going to do that and it will be fine because I'm going to give the plant that good drink once it's in the new pots and now I'm going, again, just take that out of there. You're allowed to change your mind, right!? This is the thing, you know, you have these ideas and things come to your mind! It's okay! So now I'm going to reassess because this is a slightly larger pot, so I'm going to reassess what I'm doing with the ... actually, I'm just looking now. This is about a size ... Okay, I found the right one now! Flakey Jake that I am! Right, okay, so I found the right pot! This is the right size now and I'm going to put some substrate in the bottom here. This is a slightly different shape from the plastic pot it was in, so I need to bear that in mind, but this is going to look good because I'm going to bring this caudex as the focus for the plant and it's going to look really nice. So I'm gonna just start back-filling now, mindful of the fact that caudex needs to be proud. And if this goes wrong, there's nothing wrong with taking the whole lot out again and starting again because you want to get this right, especially with a caudex plant. It's worth taking time over re-potting, if you can. You know, if you work in a nursery, you're re-potting at a rate of knots, but you know, this is meant to be a mindfulness activity you get joy out of, so try to do it in such a way that it's pleasurable. If I wasn't recording this, I'd have some music playing, I've got my cup of tea, all is good with the world! Right. So now I'm just going to press down and tap down to make sure that caudex is roughly where it should be. If you find it, she says, looking around her hideously messy shed, aha, okay, here we go! I've got a little, soft toothbrush here and because that caudex is part of the show, I'm just going to very gently brush the soil away from the caudex. It's not going to totally work because it's a little bit damp, but it will allow the caudex to be visible and make it look nice as it grows. So you can use an old, soft, clean toothbrush, or an old soft clean makeup brush, or paint brush, for this purpose. It's very useful when you're re-potting plants. This does need a good spray. So this is going to go into another basin and the pot is going to get soaked. This is kept inside at room temperature, which is about 18 degrees centigrade. So this plant has already been watered over the winter, and will be continued to be watered. It suffered a bit from the fact that this caudex has been lopsided and it's got some dried leaves, but the great thing about this plant, the ponytail palm, is it does grow up into a trunk. So it's going to be fine and I'm liking the look of that. The question I'm asking myself now is do I add a top mulch of something? I don't think I have what I would really like to use. I don't want to use Leca because that's too big basically, the Leca I've got is quite large. But I do have, at the bottom here, just a little bit, I've got some bright pink aquarium gravel, which would look cool, but I'm not going to use that because it doesn't really fit with the rest of my decor. And in the bottom of this bucket, under some pieces of slate, I've got some grit, which, we're going to use this and I think that will just finish it off and give it a nice look. It kind of matches the pot and will stop soil splashing up onto the caudex if I water from the top, which I sometimes do because I can't always soak the plant. So that's that one potted up and that's going to be, now, taken for a sink. I just need a sip of tea, if I may!

Jane Perrone
Right, last plant on the agenda is this Hoya, so let's have a look at this fellow. I've got an empty plastic pot now, which is going in the plastic pot clean pile. And let's have a look at this. Now this is a Hoya polyneura, as I said. Now, unfortunately, the plastic pot this is in has become very brittle, as plastic pots do over time. So this will need to be replaced. We're just going to have a look. This has been soaking in water, so the root ball is nicely wet. I just want to get rid of these pieces of plastic into the bin and look for a new pot for this plant and if I have any clear pots, I will use them. Let's just see if I do have any clear ones left. Let's compare the sizes of this one. So I'm going to put the old pot inside the new pot and yes, I've got it slightly deeper and about two centimetres overall wider in diameter, so that's what I'm going to use. So this one has got two plants in it, as I said: the Oxalis and the Hoya polyneura, Fishtail Hoya. When the roots have come through the bottom of the pot, it's tricky because you don't, ideally, want to lose those roots that have formed, but if they don't go through the bottom of the pot, you may end up losing them. Now, in this case, what I'm going to do is because the pot is already broken, I can actually cut the pot out of the equation. I'm just going to grab my big Chinese scissors. So I can cut the pot up here and that means I won't lose any of the roots. I'm going to have to chuck this pot anyway, so I may as well just cut the pot away instead of losing those precious roots because roots are what it's all about. That is the fundamental business of houseplants, is the roots. Whatever we think of the foliage, we need to be respecting our roots. I love these big Chinese scissors, because they're just so heavy-duty but they are scissors. So, cutting through the bottom of the pot. Now, it's a shame because this was a good pot, but it's just not working. All right, there we go. Only lost a tiny bit of root there. So that's going to go and be sorted out. I don't know if that's going to be recyclable or not, but it's done good service. And now I can look at this root ball and see what I'm dealing with. And it's a nice, healthy root ball, loads of root growth on this Hoya, and the Oxalis, well, the Oxalis is doing fine as well. So I'm going to do exactly the same as I did before. I've got - what have I done with it? - I say I've got my wool... Drop the wool at the bottom, a sparing amount. This is just the stuff that comes with when you get food deliveries, often you get this stuff and people often offer it on Facebook locally and have a big sack of it and I'll just say "Yes, I'll have that please!" and then I can use it on my compost heap, the birds love taking it for bedding, for nesting in the spring, and I can also use it for bedding for my wormery and I can also use it for things like this, also lining hanging baskets. Multiple uses, it's free, it's totally biodegradable, so an excellent thing to use if you have it available. So now I've got my compost mix again, I'm just going to add a little bit more Leca to this, give it a stir around, make sure it's still looking nice and chunky and airy. And I'm going to add a little bit of this cat litter as well and this has already got some perlite and some charcoal in here as well. So I think this Hoya's going to love this. I think somewhere it might have a little bit of peduncle action for me, which is great, and hopefully this will put a bit of a spring back in its step, to go on and do well for me. So now I've put the root ball in and I'm making sure that it's roughly where it should be, level-wise, because I don't want to be slamming it down hard and taking all the air out of the root ball. So I want to make sure that from the first time I put it in the pot, it's at the right level and then I'm just topping up with my fresh compost and the old tap routine comes in and tapping the side of the pot, tapping it down on the tray and making sure that it's all nicely situated. That is not bad at all. I'm probably, on this plant, going to add a top layer of Leca and, inevitably, the plant is going to get a little bit messy with something like this Hoya, I will probably just go now and wash it off in the shower and let it clean off the leaves so that the leaves aren't going to be affected by reduced ability to photosynthesise. But this is pretty much ready to go. It's going to need a new cache pot, I think, because the old cache pot's not big enough, so we'll look for one of those, but I'm pretty happy with that. Just going to add a little bit of Leca to the top, just to avoid mess really. I'm running out of Leca here. Let's just access a bit more Leca. Ah, there's my make-up brush! Haha! And there's another one! I've just found two make-up brushes, one after the other! Okay, in goes the rest of the Leca, on the top. I mean people say "Oh, it stops fungus gnats". It doesn't really. They're very, very clever at finding soil and they will find soil, but it does make the whole thing neater and I'm just using my scrap of wool just to wipe down the sides of the pot and make sure that it's nice and neat. So there we go! That's my three plants re-potted and ready to go and it's a satisfying feeling! I'm also going to try to record in my database that I've done this because it's good to know when things have been re-potted. And before I put this back, once I've given it a wash, I'm also just going to check with a hand lens, closely look at the leaves and just check for pest damage, signs of pests and also those peduncles that I'm looking forward to. I thought I'd seen some but, gosh, I don't know. I haven't had any flowers out of this Hoya yet, but I think it's one of my absolute favourites. It's quite a cool-loving Hoya, so, a bit like Hoya linearis, it's quite a high-altitude, cool-loving Hoya, so it does really well in my kitchen where there's not really any heating in there, so it does quite well in that room. Time for a wash-down and then away you go! Right, let's head back to the studio!

Jane Perrone
Well, I hope you gathered some kernels of information from that. It's reminded me how much I need to tidy my shed! So that's a job I'm going to start this weekend. I'll be back next Friday. And if you've got any questions about re-potting in the meantime, if I didn't answer your re-potting question, do get in touch. I'm eager to help. It's what I love to do. It's my meat and drink. But until next time, I wish you and your plants many, many wonderful things. Bye! The music you heard in this episode was 'Roll Jordan Roll', by The Joy Drops; 'The Road We Used To Travel When We Were Kids', by Komiku, and 'Dizzy Spells' by Josh Woodward. The ad music is 'Candlelight' by Jahzzar. All tracks are licenced under Creative Commons. Visit the show notes for details.

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Get the lowdown on repotting your houseplants, from spotting the signs to the nitty gritty of how to repot. Plus botanist Dr Scott Zona answers a question about plant lifespans.

Check out the shownotes as you listen…

The three plants I deal with in this episode are Sinningia reitzii (I think - waiting on flowers for a final ID), Beaucarnea recurvata, the ponytail palm, and Hoya polyneura, the fishtail hoya, with an Oxalis aureoreticulata corymbosa growing in the top.
It’s vital you know when a plant is in need of a repot. Here are the signs to look out for…

Plants wilting
Foliage feels limp
Foliage looking dull
Growth slowed or stopped
Water running straight through the pot without being absorbed
Roots growing out of the bottom of the pot
If you see any or all of these symptoms, it’s time to to the rootball out for the ultimate test - check if it’s potbound when the roots are circling around the rootball and little or no soil is visible.

3. Preparation is all when it comes to repotting! Here’s what you need to get ready…

The ponytail palm before repotting. Photograph: Jane Perrone.

Make sure your substrates are all at room temperature and not freezing as this can shock plants.
Soak the rootballs of plants you are about to repot for at least half an hour.
Make sure your potting area is clean and your new pots have been washed in hot, soapy water, then rinsed.
A soft toothbrush is useful for cleaning dirt from a caudex! You can use a soft clean makeup brush to clean leaves.
Have some rags on hand for wiping down pots.
It’s up to you if you want to wear gloves or not.
I love to repot with some music playing, and a cup of tea at my side - it’s not a race, it should be fun!
If you want to find out more about different potting mixes for houseplants, have a listen to my potting mix a-z episodes part one, two and three.
If you are repotting in a terracotta pot, ideally soak it in water before starting (one caveat - not if you are repotting succulents in the depths of winter).
When adding new substrate, frequently tap the pot to ensure the mixture settles and fills in properly.
Repotting is a good time to check plants over for pests: give them a shower to remove dust and excess soil afterwards.

The repotted ponytail palm. Photograph: Jane Perrone.

The repotted Sinningia. Photograph: Jane Perrone.

Hoya polyneura after repotting. Photograph: Jane Perrone.

QUESTION OF THE WEEK

Sally wanted to know whether plants have a defined lifespan. Botanist Dr Scott Zona was on hand to help with this one.

Dr Scott Zona is a botanist, researcher, and educator with a focus on tropical plants: you’ll find him on Instagram as @scott.zona and on Twitter as @Scott_Zona. Scott’s book A Gardener's Guide to Botany published by Cool Springs Press is out now.

Patreon subscribers at the Ledge End and Superfan level can listen to an extended version of this interview in my bonus Patreon podcast An Extra Leaf 108.

Want to ask me a question? Email ontheledgepodcast@gmail.com. The more information you can include, the better - pictures of your plant, details of your location and how long you have had the plant are always useful to help solve your issue.

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CREDITS

This week's show featured the tracks Roll Jordan Roll by the Joy Drops, The Road We Use To Travel When We Were Kids by Komiku and Dizzy Spells by Josh Woodward. The ad music is Candlelight by Jahzzar.

Houseplant care basicsJane PerroneMarch 24, 2023Repotting, leaf botanyComment