Episode 280: Citrus and other fruits to grow as houseplants
The variegated Calamondin orange makes a decorative specimen in a pot. Photograph: Edible Houseplants by Laurelynn G Martin and Byron E Martin.
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Transcript
[0:01] Jane Perrone AD
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[1:15] Music.
[1:31] Jane Perrone
This week's episode is zesty and fruity. Yes, we're talking citrus and other potted edible fruits. Plus, I answer a question about a monstera that needs taming. And there's an important update about the next episode of On the Ledge that you won't want to miss.
Logee's Greenhouses in Danielson, Connecticut in the US is one of the best known sellers of indoor plants and indeed one of the most historic. It started out as a cut flower business back in 1892 but the Logee family quickly got into citrus and the rest is history. They've been growing wonderful houseplants from begonias to gesneriads since then and today I'm delighted to be joined by the latest scion of the Logee family, Byron E Martin who is here to talk about book edible houseplants which contains a wonderful array of citrus you can grow in containers in your house as well as some other fascinating fruits. If you've ever bought one of those citrus from the supermarket or the garden center, cute little potted things covered in fruit and found that they've died very very quickly, this is the episode for you. We also cover the main ways that you can kill your beautiful citrus, why a terracotta pot really helps and why light is, as is so often the case, absolutely key.
[3:35] Music.
[3:43] Jane Perrone
Byron, thanks so much for joining me on On The Ledge. We're here to talk about your book about edible houseplants and I think one of the key edible houseplants in my mind are the citrus family. When we think of citrus, I think we're often just thinking of the fruit bowl favourites like lemon, orange, grapefruit, but there is a huge variety of hybrids we can grow indoors. Is there one really good starting point, a particular citrus that's good for anybody, particularly if they struggled with citrus in the past.
Byron Martin
Basically, citrus are great container plants. And the book was really written on plants that will fruit in containers. And that's our work here at Logee's. We're tropical plant growers in pots. We don't grow mangosteens because they get to be much too big or coconut palms because they get to be much too big. And citrus are really a great plant for a container, in that you can maintain the size of them by the size of the container and also by using a pair of pruning shears. And those two things, which you can do with most of the fruiting plants that we list in the book, can contain them so that they fit into a home. Now, not everything fits into a window. As far as citrus goes, the greatest challenge to growing them is to keep your root health. The citrus can be either grown on their own roots or they can be grown on a grafted understock. And the biggest challenge to growing them is root diseases. And these are pathogens that get in and damage the root system. And usually it happens during the winter time and then the plant collapses on you. So all of the efforts to be successful in citrus need to be directed towards keeping a healthy root system. And for those of us in container horticulture, we're constantly knocking pots out and look at roots. So I always say that the top of the plant is a mirror of what's happening under the soil. And this problem in growing container citrus is not necessarily in all citrus because there are some varieties that are much hardier than other. And also when you plant them in the ground, as in citrus groves in areas where they're grown outside, they usually don't see these issues, but we as container growers are faced with this constant challenge to keep our roots healthy, and to do that you need to know that the diseases that are causing this are what I call water molds, and these thrive under damp, cool conditions. And the way to get around that is obviously to grow the plant drier. Citrus take tremendous amounts of stress, even to the point where I have seen plants that I thought for sure they would be dead, or were dead, and you give them water and they come back. So the first thing is to make sure that you're growing them on the dry side.
The second thing is to grow them in clay or terracotta pots, which will give you a quicker dry down. and the third thing is to not over fertilizing them. So over fertilization of any plant will create soft tissue. The soft tissue makes them more susceptible to these diseases.That said, citrus can have a challenge as many plants do. When you move them in from outside, you get a certain amount of leaf drop.And that actually happens in the greenhouses when we move plants from outside and even into the greenhouses, we get this leaf drop. And that is not going to kill the plant, but it does make it look a little thin when it goes through this process. But you know, then all of the things being equal on citrus, you need some sunshine on them.They won't grow very well in diffused light. They can grow, but they don't do very well. And obviously the fruiting potential is diminished greatly. And if you are struggling with root disease, and you'll find that out when you tap them out of the container and look at their roots, it's better to grow them a bit on the warm side. So we know that citrus can take it down below freezing. However, we don't want to grow them in a cold spot where the soil will remain chilled and wet over a long period of time. And in the marten home, that's usually not a problem but you know there are many areas that people grow plants indoors and so you want to choose one that at least stays above 65 degrees or I don't know what that'd be probably 20 degrees centigrade or something like that.
Jane Perrone
When we're looking at the roots for the uninitiated what are the problems we might be seeing? Is it roots that have turned to mush? Is it a bad smell? What kind of symptoms are there of a root problem?
Byron Martin
Well no what will happen is is the plant will go into a decline. It'll drop its leaves. You can also get chlorosis in the leaf system where the plant is suffering from nutrient deficiencies. But, you know, I mean, I've watched it over many years. The first thing that happens is the plant loses its luster and it starts to drop leaves. And it's just, it's simply a matter of the plant can't take up water and then it can't take up fertilizer. And, you know, the most important thing is check your roots. I do that all the time, all kinds of plants. We're always looking down below the soil level to see how the crops are growing. And you can, and remember, roots don't die from old age. They die from usually a pathogen that affects them. And it's Pythium and Phytophthora are the two main culprits in it. And they can be very hard to control, even in commercial horticulture with chemicals. These diseases have mutated through a lot of the fungicides and so on. So, really culture is the best thing to use. And also your potting mix is important. It needs to be really well-drained and have porosity to it. So, people often don't think about roots as breathing, but they do. There's an exchange of carbon dioxide and oxygen between the root and the air that's around it. And so, you want an open mix for that. I mean, going outside and getting some heavy garden soil is probably not a really great idea.
Jane Perrone
Do you need to go and buy the specialist citrus potting media that you see in the shops?
Byron Martin
No, probably not. You just need to get a good potting soil. They like acidic soil and not maybe as acidic as Aracaceae, but they don't like neutral. Neutral will cause all kinds of nutrient deficiencies. and so you really like to grow them at 6, 5, 5 to 6, something like that, in terms of the pH level, and then they take up nutrients very freely.
[10:32] Jane Perrone
And if you have found that your plant is suffering, is there any bringing it back from that chlorosis and leaf drop if your roots have started to be affected by those kind of fungal problems or disease problems rather?
Byron Martin
Right. So a lot of times people will ask the question, well, should I throw out all the soil and clean the roots off and repot it? And the answer is no, unless the soil is, you know, got a really high pH or. Is very heavy, and the reason being because that disease has gotten into the root system that will be there forever. And so you've got to culture it around that. It's very easy to do, actually. People overwater their plants and they don't have a quick enough dry down. Remember those two things, and then back off on the feed, which would happen in late summer. You don't want to be feeding going into the wintertime. You want to get that root system strong and tough and hardened off so that it can resist the pathogens that are, you know, there. And the other thing that we are using more in our culture here, and I don't know if homeowners could get a hold of it, is we're using a lot of biologicals for drenching. And they're actually working pretty well. And those are bacteria and fungus that colonize the root systems of the plant and resists the diseases.
[12:02] And I know there's maybe a couple maybe on the retail market, but a lot of this stuff is just still on the commercial side of things. But hopefully that will be something that comes forward as the time goes on. Because they really, if you're persistent with it and you do it regularly, we've seen amazing results, way beyond what the fungicides will do. That plants actually can recover from it.
Jane Perrone
What we do have here, which I don't know if is exactly what you're talking about, is mycorrhizal fungi inoculants. Is that what you mean?
Byron Martin Yes, and these are specifically chosen or selected because of their antagonists to these diseases. So they're not necessarily just mycorrhizae that's going to create a, and those are good also, but create, you know, this balanced rhizosphere. They really are targeted towards these two pathogens that I spoke of.
Jane Perrone
Got you. And I mean, once you've got past the stage of actually making your plant survive for more than a few weeks, there are some really lovely different citrus to grow. A lot of people though buy their plants in fruit from the garden centre or sometimes even here I've seen them in supermarkets and then they don't last very long. I suspect that sometimes they are sold almost like a living bouquet. They're not expecting anybody to get these plants past a few weeks, which is not very sustainable, obviously. But if you do buy one of those, or if you've got one of those, have you got any advice on how to make sure it does survive past that initial?
Byron Martin
So the first thing to do is it's going to be a grown in probably a plastic pot, and you want to get it out of that. And when you get it, taking it out of the pot, examine your root system. They should be all alive and healthy. if there's a lot of dead roots there, or the root system has already collapsed, which is very possible, then you're obviously up against a greater challenge. The holding of fruit on citrus in containers, it stops the growth or slows it down considerably. So sacrifice the fruit, take that off, get them into a clay pot, and then stop managing the water. And I would suggest to anybody that is trying this, see how far you can go with dryness. And learn that point of dryness that the plant will survive, yet will create that healthy root system. And as I mentioned previously, I am totally amazed at the dryness that these things can take. We grow them up on drip lines in the greenhouses. And Once in a while, one of those emitters comes out and the plant hangs there over a hot weekend when nobody's in there checking on it. And I come back, swear they were dead, giving them water and they all just sprout right back out. I mean, really desiccated. So remember, they can take it drier than you think. So the total leaf loss is not necessarily the end of the road then, from what you're saying, if it's been caused by dryness? Total leaf loss is not a good sign, but I have brought many, many citrus back from the edge of collapse, even to the point where there are hardly any leaves on it. The thing is, is that these diseases affect the feeder roots that are out in the pot, and they don't affect the trunk roots. So, those heavy roots that are in the soil in the container are not really affected and they can re-sprout from that. And, you know, it takes time to have them recover, but once you get the handle of, you know, soil moisture and aeration to the soil and, you know, as I've mentioned many times, the proper watering, you'll see that they'll re-sprout out of it. And a lot of times, I have so many of our customers that talk about, you know, every year I bring it in and it drops all its leaves and then February, it starts sprouting and it goes into a heavy bloom and you know, the cycle is repeated over and over again. And citrus that are really stressed flower heavy, so that root rot probably initiated some of the budding on it. But they do recover from it. So I don't, you know, once it's going backwards or it's under stress, like I don't throw it out, just try to readjust the environment, particularly root environment. And remember, they do need sunshine. You know, a lot of people will pull them back from a window or grow them in a north window or northwest window or something like that. And, you know, that's not really helping the situation and they need that sun energy to really get going.
Jane Perrone
So do they really need your absolute sunniest windowsill? Is that where you'd be putting it if you were bringing one indoors?
Byron Martin
Yeah, you've got to take up the room. But you know, they can be held as fairly small plants. And I'm telling you, a healthy citrus plant, regardless of what it is, can take a very, very severe pruning and still come out of it. And obviously, the pruning time needs to be when they start activating growth in late winter and springtime, so that they have a chance to recover. You don't want to prune them at this time of year.
Jane Perrone
Absolutely. So by combining a bit of root pruning to keep them in the same size pot, rather than continuously upgrading the pot, plus that pruning of the foliage, you can keep them to a decent size where you can have them indoors successfully.
Byron Martin
We don't do a lot of root pruning here. We do a little bit. There are plants that actually push themselves out of the pot so you can't get water into them. But we don't root prune citrus. They live in those pots for decades. We do give them bigger pots than maybe you'd want on a windowsill, where we do by inches here in the US, we need 12 to 14, 16-inch pots, which are really very large. And particularly if they're clay, you don't want them that big, unless you've got a big window. You don't need to root prune them. It's just take the top back as is needed. And they tend to grow in different directions, so you can make them symmetrical when you do the pruning. And you need to remember that, depending upon the citrus you grow, so lemons and limes grow pretty much constantly. I mean, they do shut down in the winter a little bit, and they can flower and fruit periodically throughout the year. They do have, most citrus flower in late winter, but the lemons and limes can flower in late winter, and then they can flower, you know, during the summer and so on. And so, the pruning on a citrus, when you make that cut, wherever you are, there's going to be a growth that comes out of it, and that growth needs to harden off and then the next growth is where the flowers form. So when you make a cut on citrus, that flush that comes out first has to harden off. So you've got two cycles of growth. Now, if you're growing a tangerine or an orange or grapefruit or something like that in a container in the north here, we don't get but one, two, maybe two growths a year on them, whereas lemons and limes, you can get three or four. And so the pruning is gonna reduce your flowering. You need to be aware of that when you make the cuts.
[19:21] Music.
[19:31] Jane Perrone
More citrus tips coming up soon but time for a wee bit of housekeeping. I am bubbling with ideas for 2024 so if there's anything you'd like me to do then do get in touch and let me know. Maybe there's a species of houseplant you just don't think I've covered enough or you'd really like another Q&A or maybe you want me to talk to your local, gardening group in person or on zoom. I don't care. I just want to know what you want in 2024. So do drop me a line on the ledge podcast at gmail.com. And already in the on the ledge inbox was a lovely message from Pamela, who had heard something on another podcast that caught her attention. This was the Ologies podcast with Alie Ward, which I do think is a rather marvelous show. They did an episode on pomology aka the study of apples and mentioned in that show that the off-gassing of an apple can help a bromeliad to flower and Pamela in Bellevue Washington wanted to share that with me. Now this is interesting because I've always associated this particular fruity superpower with the banana. The gas is the same, ethylene, both apples and bananas give off ethylene which helps fruit and flowers to ripen if provided in certain quantities. If you've never seen a bromeliad before what I'm talking about is those rosette shaped, fleshy leaves. Plants that have very dramatic flowers. These are epiphytes, they grow in trees in South America. ]You often see them in tropical greenhouses looking all gorgeous, but sometimes they can be a bit shy to get going with that flower spike. So we're talking about things like the varies, the acme, the bilbergies and so on. All of these are classed as bromeliads. And yes, you can stick some apples or some bananas next to a bromeliad and it will hopefully move along the flowering process somewhat. The only thing you need to be aware of with ethylene is that you can have too much of a good thing. So the Victorians experienced this because their gas lighting gave off large amounts of ethylene and too much ethylene will kill plants, send the flowers dropping and spell imminent decline. So yeah, you've got to get the ethylene in the right amount. An apple is going to give off probably just about the right amount to produce the effects you're looking for without killing your plant. You can also use apples and bananas to ripen things like tomatoes and chilies. [22:35] And I do talk more about this in the Aspidistra chapter of my book, Legends of the Leaf. But thanks for sending that in. I love tidbits like this, so do keep them coming, listeners. And thank you to listeners who have dipped their toe into the warm and friendly waters of my Patreon. [22:57] Offering this is the monthly subscription which brings you benefits. Cian has become a legend, Kate has taken up a free trial and then become a legend, Kyle also took up a free trial and Jason upgraded from legend to super flan. Super flan? I mean I'd love a super flan. Who doesn't love a nice tasty flan? But I actually meant Superfan. I don't know if flan is a British thing. Do you have flans anywhere else in the world? Oh I'm not sure. Oh well, you'll have to Google it if you're not sure what a flan is. Onwards and upwards - and finally James became a crazy plant person. Thank you to all of these individuals and I am in the midst of writing my December mail-out cards and remembering how brilliant you all are. So those will be going out probably the start of December so if you are a Patreon at the legend or superfan level, do keep an eye on your letterbox. Also, just a heads up, next week and the week after are going to be unusual and that's because I am not just putting out a podcast in two weeks time as normal. No, no, no. I am offering up my top 10 begonias. Top 10 begonias. These are going to be the top 10 begonias that can grow in regular room conditions. We are not covering the terrarium begonias. We are covering the ones that will grow in the average room. And I'm going to chop things up. So this will be coming out starting from Monday, the 27th of November, running through to the Friday that week, and then Monday to Friday, the following week. Each day, I'll be covering a different begonia. And in one of those episodes, I'm not quite sure which yet. I will also cover my tips for caring for begonias. So I think that's going to be a really interesting little series. You're free to disagree with my choices, but they are the ones that I think top the charts when it comes to begonia loveliness. So you can start listening to that from next Monday, hopefully a bit of a pre-Christmas treat for you all. Oh gosh, I said the C word. Apologies. Right, that's the housekeeping done. Dustpan and brush goes away. And now it's time for question of the week. And this came in on the house plant fans of On the Ledge Facebook group from Laura, who describes her Monstera deliciosa, aka the Swiss cheese plant, as having a little shop of horrors moment. And that's because its aerial roots have attached themselves to Laura's record cabinet. Oh dear! Laura thinks the plant needs repotting and a moss pole and wants to know if it's suitable to wait until spring or if it's too urgent and needs doing now and Laura is in the UK. Now various other members, so looking at Laura's plant, I'll stick a photo of it in the show notes, it looks fairly typical to be honest for a monstera of its size, it's got about well, it's just starting to get its first holes and it's got about six or eight leaves in total, But it is doing that spaghetti monster thing that Monstra Deliciosa just do. This is the way they operate. I would say that Laura would be fine to repot it now. Yes, we're coming into winter, but this is a plant that does tend to grow year round and provided Laura doesn't put it in a bucket when it's been in a quite a small pot, as long as that upgrade is only a marginal one of say a pot a couple of centimeters wider in diameter on each side, I think it'll be fine and it'll give the plant more surface area into which those aerial roots can be tucked. It's worth pointing out with aerial roots there is stuff you'll see online about putting the roots into water. Yes you can do that if you really want to. You can cut them off, they will regrow but you can cut them off if they're getting in the way or you can try to redirect them into the pot, now that in itself can be tricky once they have hardened off as they emerge they do tend to get quite inflexible but that said it doesn't really matter what you do with them you can just mould them to your ways and this is what you really have to do with the Swiss cheese plant, it is such a malleable plant that can be hacked back and used in different ways, but if you let it, it will start attaching itself to all kinds of things around your house, particularly any wooden furniture, because it thinks they're a tree. The dangers of leaving this Monstera in the same pot for a long period over winter is that it might just get really unhappy and might exacerbate existing problems with coping with winter. So I think a little pot upgrade is no harm at all Laura. I would just use multi-purpose compost with maybe with some added John Innes if you can access that kind of thing as regular listeners will know my base for my compost.
[28:19] For my compost for indoor plants is Melcourt Sylvagrowwith added John Innes and to that I would add a handful or two of something like Expanded Clay Pebbles or Perlite or even Fine Orchid Bark just to open up that mix a little bit and introduce a bit more air. But I think this plant will be fine Laura. Monsterers gonna monster and this is what they do but you can help them along with the biggest bigger part that you can maybe get those roots tucked into or else just chop them off. Chop them off right at the base of the stem though because if you chop them off kind of halfway along what you'll find is that they will branch and branch again and turn into even more of a spaghetti monster look. So that's my advice on Monstera deliciosa. If you've read my chapter in Legends of the Leaf you'll know that there's loads more to this fascinating plant. Do go and check that out and if you prefer to listen rather than read, then Legends of the Leaf is available as an audiobook now. Still not available on Audible, which is rather annoying, but it should be coming to Audible soon, soon, soon. I'll let you know as soon as it's there. But Laura, thanks for your question. And if you've got a question for On the Ledge, you can post in the Facebook group Houseplant Fans of On The Ledge, which I urge you to join, link in the show notes, or you can just email me ontheledgepodcast@gmail.com. That's the Q&A wrapped up and back to my chat with Byron Martin from Logee's. Let's get back into the lovely world of containerized edibles.
[30:00] Jane Perrone
Aside from citrus, there are some amazing species in this book. Can you tell me, I mean there was one, I can't remember the full name of it, but it had a peanut butter element to it. Can you tell me about one of your favourite, one of the sort of the really unusual fruits in here that we may never have come across?
Byron Martin
Oh, the Bunchosia, the peanut butter fruit. That's an interesting plant. It doesn't fruit as heavy as we would like in pots, although occasionally we see it and we don't know why. And the fruit gets very soft and tastes like peanut butter, but it's sweet. So it's peanut butter with some sweetener added to it. But, you know, we have some crazy fruits like the noni, which is that citrifolia that actually is a Pacific Island plant. You find it on the, throughout Hawaii and all the islands south of there. And it's actually a really good container plant, but the fruit is pretty bad. I mean, people eat it. It's called famine food. And there was this whole period probably two decades ago where there was health benefits from it. And there was actually, Hawaii has some plantations where they're still manufacturing the ferment of it. They take the pulp off and ferment it. But it's kind of a cool plant to grow. The flower actually sort of is always the fruit and it just keeps growing. And then when the fruit gets soft, it obviously falls off the tree, but it's really not something that you want to enjoy. It has a terribly strong smell and it tastes like it smells, but that's really a pretty cool plant, actually, for anybody that wants to get out on the edge of fruiting plants. We also have a Manilkara, or sapodilla plant that we found in a nursery that's really a dwarf. So, the sapodilla is actually a very large tree. It grows up to probably 40 feet or 60 feet here in tropical areas, sort of like our maple trees or your oaks in the UK. And you know, it's not something that fruits very well in pots. I mean, it will, but you got to wait a long time. But this thing, 'Silas Woods', unbelievable amount of fruit you can get off of that particular plant. And the ones I've seen, which we originally got from, they were no more than eight feet tall and just covered, they, matter of fact, they produce so much fruit, they can't even get scion wood, it has to be grafted scion wood off of them. They have to strip all the fruit and flowers off just to get the plant to grow. Wow, that sounds like a really good cultivar. And was that was that just a chance find? I kick around nurseries like all of us do all the time. and a friend down in Florida had it. And because they're in Florida, you know, plants like that are not necessarily really... because you can grow a bigger tree and it's kind of small. And the same thing with our carambolas. We have two varieties that are very dwarf and heavy, heavy fruiters. I mean, there's a picture in the book there of one that's probably three or four feet tall covered with fruit. And, you know, it's just it's not something that people in tropical areas really want because they can grow so much more, I guess.
Jane Perrone
Yeah, that makes sense. It depends where you're where you're at as to what you're actually the qualities you're looking for.
Byron Martin
Right. Well, that's what we do, which constantly trying to find those plants, because most plants, not all, but most plants actually have a smaller form to them if you can find it. And then there's plants that, you know, like a muntingia, which is the Jamaican Jamaican cherry, I think is a common name for it. That plant in Florida, which is one of the tropical areas we often go to, it'll grow 12, 14 feet in a year. This thing comes out of the ground and I kept looking at the thing going, there's no way that's going to live in a pot. And finally, I got a piece of it from a friend and brought it home. And I found out that if you put it in a pot, it squats it right down to a nice little bush. And it never grows crazy like it does in the ground. And, you know, in terms of fruit, that thing is very, very productive as a container plant. You can probably maintain them at about four feet, four or five feet in height, so you do need some room inside, but they're interesting. They taste like cotton candy, the berries do, and they ripen in the morning. You can go out and pick a handful of them, and then in the afternoon you go back and there's another handful ready, and the production just keeps on going throughout the summertime. They're just winding down now. We've moved them in because of the freezing weather, but it's a very containable plant that you would have never thought it would do that until we gave it a try.
Jane Perrone
For people who perhaps have a tiny windowsill, is there anything in the book that you can recommend that maybe keeps it, you know, two or three feet for somebody who really is limited for floor space and just can manage a windowsill pot?
Byron Martin
Yeah, so we've mentioned citrus and there are many kinds of citrus. There are, we have an Australian blood orange that grows, actually the picture on the front cover of the book, that's one of our mother plants, and that's as big as it gets. What you see, it's a weeper, so you have to trim back the weeping branches of it. You know, there's the famous calamondin oranges, which, you know, are really sour, and then of course lemons, limes. The key lime is actually a pretty small grower. And remember, all of this is about pruning shears. And then there's some ornamentals like the myrtifolia, citrus myrtifolia, that's a myrtle leafed orange. That thing is really a small grower on its own roots. But this, and the citrus is edible. It's just that like the calamondin, it's quite sour. I mean, if you give me three feet of window space, There's a, you can do a lot with citrus of any type. The only ones that probably wouldn't work would be a citrons. They tend to get really tall and big before you do anything. And also pomelo, grapefruits, those things get pretty big. But all the others are very manageable as small plants. You know, we have the ujukitsu orange. It's a sweet lemon called ujukitsu, but it's actually an orange. What it is, is it's a tangelo with a yellow skin. And it's probably the sweetest fruit that we grow in the citrus line here at Logee's. It is absolutely pure sugar. I assume that that's just its ability to do it in a greenhouse, whereas you go into tropical areas or citrus fruit growing areas, there's a lot of sweetness in all of them.
Jane Perrone
That's great to hear. Good to have lots of different options there. I had a question from a listener who lives in central Scotland, which gets quite cold. He has a lemon that has flowered but not fruited before. I'm not sure whether he's bringing this inside in winter. I jolly well hope he is, because I suspect Scotland's getting down to about, I don't know, probably at times minus 10 centigrade, which is, I don't know what that is. Very cold anyway, but well below freezing. He's had problems with getting this to fruit, and he's wondering if it can fruit successfully at his latitude. What's the answer there, Byron? Is it possible to grow citrus successfully up in Scotland?
Byron Martin
Definitively, I probably don't know, because I've never grown through in Scotland, but I don't see why it's not possible, providing, I mean, because, you know, you have really long days in the summer, so you're going to make headway there. And you have to maintain temperatures above, well, above freezing, but as we mentioned before, it's better to be, you know, in the 60s, Fahrenheit that is, during the wintertime. And if he has a lemon that flowered once and still grows but never fruited, then the question is, where did it come from? Was it a seedling? Was it a cutting? Was it grafted? What was the variety? because lemons can actually, so many citrus grown from seed can take a very long time, so like an apple tree, you know, you have to go 10, 15 years before you see the fruit on them. But others come on very quickly. Citrons are one that do, and I've had people that have grown lemons that the fruit did relatively quickly. I mean quickly meaning three or four years from the time the seeds are planted until they come into fruit under good growing conditions. So in his case, the question is, where did it come from? And then the other thing is, like, where is he growing it during the winter? Because even though you're, you know, you have these super short days, and so on, there's no reason why that plant, as long as it stays green, you know, and doesn't go backwards. And we talked about what causes that there's no reason why that can't as soon as it hits, you know, the long lengthening days, it starts growing again. And that's, and of course, that's the period when it starts to flower. So, is he pruning the plant? Is it in a sunny window during the wintertime and outside in the summertime? It's the growth that was just finished that's going to produce the flowers in late winter. So they're going to slow down the growth, stop growth, and then that next flush is where your flowers are going to form. And there are some nutrient issues with such plants that don't fruit. I mean, you want to make sure that you're not given excessive nitrogen. But I think that certainly in a sunny exposure, even in Scotland, you should be able to do it fine.
Jane Perrone
Well, that's good news for Peter. And one other listener question from Meg, who wants to grow the Thai lime Citrus hystrix. Because Meg wants to use the leaves in Southeast Asian cooking, which hadn't occurred to me, but of course that's another element of that particular citrus that you can use. So she's got lots of indirect light, protected from drafts and a constant temperature of 19 degrees centigrade. Does that sound like a good spot for that particular citrus?
Byron Martin
The indirect light is what's causing the problem. So get it to some sunshine. They're not, you know, I think I did read that, I think they said there was a monstera growing fine.
Jane Perrone
Yeah, yeah, she said that she had a monstera there as well.
Yeah, no, that's not gonna, you're not gonna get much out of that. Yeah, I think that's probably one of the things people are underestimating is this need for really good light for these citrus. Yeah, the funny thing is that our eyes pick up light different than plants do, right? We go into a room, there's windows, the room's filled with light, but you take that plant away from that sunny window or the bright window situation and bring it interior and it just, it's a cave, basically.
Jane Perrone
Absolutely, yeah. I think it's so key. Thank you so much for joining me today, Byron. It's been a delight. And I'll put all the details for Logee's and the book in the show notes. But thank you so much for sharing your expertise today.
Byron Martin
Great. Great to be with you.
[41:27] Music.
[41:35] Jane Perrone
Thank you so much to Byron Martin of Logee's for joining me, and if you want to find out more about Logee's, the lovely book Edible Houseplants, or any of the species and hybrids that we've talked about in this episode, do go and check the show notes. There's a full transcript, plus notes that are well worth consulting. That's all at janeperrone.com.
[41:58] Music.
[41:58] Jane Perrone And that's all for this week's show. I will see you on Monday for part one of the On The Ledge Begonia Takeover. Until then, have a marvellous week. 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, Autumn Sunset by Jason Shaw and Holiday Gift by Kai Engle. All tracks are licensed under Creative Commons.
[42:41] Music.
Struggling to keep your potted citrus alive? I chat to Byron Martin of Logee’s Greenhouses to find out his top tips for keep lemons, limes and more alive in your home. Plus I answer a question about taming a Monstera.
This week’s guest
Byron Martin is president and co-owner of Logee’s Greenhouses in Danielson, Connecticut in the US. The business has been in the same family since 1892. You can read about the history of Logee’s here.
Edible Houseplants by Laurelynn G Martin and Byron E Martin is out now, published by Storey Publishing. Details here.
Chapters
0:03:43 Interview with Byron Martin begins
0:13:30 How to save a potted supermarket citrus
0:14:45 Why citrus like dry soil, and what to do if your citrus loses all its leaves
0:16:33 Pruning tips for citrus
0:19:31 Housekeeping, Patreon update and news about my upcoming Begonia series
0:30:32 Part two of my chat with Byron Martin
0:33:19 Citrus options for small windowsill: Australian blood orange, calamondin, ujukitsu orange
0:39:32 Understanding the growth cycle for flower formation
0:41:58 Music credits
Check these notes from my interview with Byron as you listen…
Citrus need maximum sunlight to thrive, so put them in your sunniest spot. The kind of bright indirect light that, say, a Monstera deliciosa will enjoy won’t be enough for a potted lemon. Use a growlight to boost light levels, especially in winter.
Citrus can be put outside in the summer, but bring them inside as temperatures drop and expect to experience some leaf fall when this happens - this doesn’t mean your plant is dead - it should resprout!
Citrus benefit from a prune in late winter and spring as they start to put on new growth.
Citrus can be either grown on their own roots or they can be grown on a grafted rootstock.
They are prone to root disease such as Pythium and Phytophthora so the greatest challenge to growing citrus is to keep your root health.It really helps to keep citrus on the dry side: they can deal with a huge amount of dryness around the roots. Use a terracotta pot to ensure air is reaching the roots.
You don’t have to buy specialist citrus compost, but remember that they like a slightly acidic potting mix: a pH of 5 to 6 is ideal.
If you buy a small potted lemon or other citrus from a supermarket or garden centre, it will probably come in a plastic pot - it’s advisable to repot into a terracotta pot, making sure that the roots look healthy and firm.
Although the fruit on these plants may look nice, it’s wise to remove it so the plant focuses on new growth. Make sure the potting mix stays on the dry side.
Order your copy now!
Houseplant Gardener in a Box is now out worldwide!
Grow happy, healthy houseplants with the help of these simple, illustrated cards. The 60 informative cards, illustrated by artist Cody Bond, and 32-page book packaged in a giftable box.
I answer hundreds of questions, including: What sort of plants love a bathroom? How can you bring an orchid back into flower? What needs regular watering, and what doesn’t mind if you forget? What can you put on a sunny windowsill, and what will send foliage tumbling attractively from a shelf? Drawing on years of experience and research, her cards provide sensible, practical, and inspiring advice. The accompanying book will guide you through the process of selecting plants, and Cody Bond’s beautiful illustrations will inspire you along the way. Order your copy now from all good bookstores (and lots of plant shops too!)
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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, Autumn Sunset by Jason Shaw and Holiday Gift by Kai Engel.