{"id":12016,"date":"2022-01-26T01:20:55","date_gmt":"2022-01-26T00:20:55","guid":{"rendered":"https:\/\/afabego.fr\/?p=12016"},"modified":"2022-02-23T00:50:32","modified_gmt":"2022-02-22T23:50:32","slug":"cultiver-des-begonias-en-terrarium","status":"publish","type":"post","link":"https:\/\/afabego.fr\/en\/culture\/cultiver-des-begonias-en-terrarium\/","title":{"rendered":"Growing begonias in a terrarium"},"content":{"rendered":"
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Why grow a begonia in a terrarium?<\/h4>\n

The question might be: where do you grow your begonias? Possible answers: in my flat, in an unheated conservatory, in a \u201cspare\u201d room of the house, in a greenhouse. To grow begonias in good conditions, as close as possible to their natural living conditions \u2013 and this is also true for hybrids \u2013 you need to give them:<\/p>\n

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  • High humidity<\/li>\n
  • Warmth<\/li>\n
  • Light<\/li>\n<\/ul>\n

    You cannot grow your beloved begonias properly in a flat (too dry), in the house (too dark) or in a conservatory (too cold in winter if unheated). If you do not have a heated, humid, well-lit greenhouse, the only way to give your plants all three elements \u2013 warmth, humidity and light \u2013 is to grow them in \u201cmini-greenhouses\u201d or terrariums, where it is much easier and cheaper to create and maintain these three basic conditions.<\/p>\n

    Indeed, once these conditions are in place, growing in a terrarium keeps them stable for several weeks without any intervention. As you will see, a terrarium is easy to set up, growing plants in it is really very simple, and you can even go away and leave your plants for several weeks!<\/p>\n\n\t\t<\/div>\n\t<\/div>\n<\/div><\/div><\/div>\t\t\t\t\t\t\t<\/div>\n\t\t\t\n\t\t<\/div>\n\t\t

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    Which container?<\/h4>\n

    Any transparent and \u201clarge enough\u201d container will do, whether glass or plastic: being transparent, it lets light through; being airtight, it keeps the humidity stable; and it can easily be placed (and moved) somewhere practical, suitable, warm and bright.<\/p>\n

    The photos show that there are many possible models. Aquariums are particularly suitable for growing small begonias, whether \u201cbowls\u201d or classic rectangular tanks. You can use a glass bottle if it is large enough, a plastic one to start cuttings, a mini-greenhouse from a garden centre, a glass microwave dish covered with a cloche, a saucer with holes also covered with a cloche, a freezer container, etc., etc. Our American friends can buy handy terrariums specially designed for growing plants. If you know how to cut and glue glass, you can also make \u201cmade-to-measure\u201d terrariums yourself, in particular ones big enough for large plants.<\/p>\n\n\t\t<\/div>\n\t<\/div>\n<\/div><\/div><\/div>\t\t\t\t\t\t\t<\/div>\n\t\t\t\n\t\t<\/div>\n\t\t

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    One important point: you must be able to\u00a0close\u00a0<\/strong>and\u00a0open the terrarium<\/strong>\u00a0easily<\/strong>\u00a0: the best option is a sheet of glass (cut to size, with smoothed edges) that closes it without blocking the light and can be slid aside for ventilation when needed, or a piece of cling film with a few holes in it.<\/p>\n

    Humidity, warmth and light<\/h4>\n

    To get satisfactory humidity in the terrarium, the substrate must be moistened at the start \u2013 I did say \u201cmoistened\u201d, and this is done before the begonia is planted (if you push a finger into the substrate, the hole should not fill with water!). Condensation on the sides is a sign of good humidity, which is then close to 90%. There is no need to water the plant (except when planting it, so that the roots are in contact with the substrate): as the terrarium stays closed, the humidity will last for quite a while. You can also get good humidity by growing the plant on living Sphagnum moss: besides its antiseptic effect, this moss \u201cself-maintains\u201d the humidity in the terrarium.<\/p>\n\n\t\t<\/div>\n\t<\/div>\n<\/div><\/div><\/div>\t\t\t\t\t\t\t<\/div>\n\t\t\t\n\t\t<\/div>\n\t\t

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    Providing\u00a0warmth<\/strong>\u00a0in winter is important: begonias cope badly with cold, especially in a very humid environment, which is the case in a terrarium. So place it near a source of heat; this is easy in a house or flat, less so in an unheated conservatory. You can also lay an electric heating cable in the bottom of the substrate, if the terrarium is large enough and can be drilled to pass the wires through. These cables are easy to find in garden centres or aquarium shops. Beware: these cables do not heat the terrarium, they heat the substrate, and this form of heating tends to dry it out! In any case, it is much easier and much cheaper to heat a terrarium than a conservatory or greenhouse!<\/p>\n

    In nature, even in the relatively dark rainforest, begonias receive a certain amount of\u00a0light\u00a0<\/strong>which, through\u00a0photosynthesis<\/strong>, allows the plant to feed. In the tropics where they live, day length varies from about 10 to 14 hours. In France the variations are greater: in summer the day lasts about 16 hours, but only 8 hours in winter. Artificial light can make up the shortfall in winter. While light is sufficient in a conservatory or greenhouse, this is not the case in a house or flat; you can then keep the terrariums \u2013 usually in the house or flat \u2013 under\u00a0artificial light<\/strong>\u00a0all day, i.e.\u00a0for about 14 hours<\/strong>. (Several articles have been written about which lamps to use: see the B\u00e9gofil.) Most begonias grow well under artificial light.<\/p>\n

    The substrate<\/h4>\n

    What is true for growing begonias in pots also applies to terrariums: the substrate must be\u00a0light and airy<\/strong>\u00a0and\u00a0free-draining<\/strong>. Unfortunately, it is hard to find a compost suitable for begonias in garden centres; you can buy it from suppliers to professional growers: it is relatively cheaper and better suited (it is a\u00a0non-composted, peat-based compost<\/strong>), but it comes in 70-litre bags. You can club together to share the cost.<\/p>\n\n\t\t<\/div>\n\t<\/div>\n<\/div><\/div><\/div>\t\t\t\t\t\t\t<\/div>\n\t\t\t\n\t\t<\/div>\n\t\t

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    How do you\u00a0aerate\u00a0<\/strong>or\u00a0lighten the compost<\/strong>\u00a0? By adding\u00a0perlite<\/strong>\u00a0(expanded volcanic rock in the form of white granules). Usually about one third perlite is added, but you can go up to two thirds for saxicolous plants (those that grow on rocks). On the other hand, avoid vermiculite, which holds too much water (it can, however, be used for cuttings). Perlite gives a\u00a0better-draining substrate, because it is more airy<\/strong>. You can also put a layer of a few centimetres of perlite or\u00a0clay balls<\/strong>\u00a0in the bottom of the terrarium, before the compost. This will ensure good drainage and stop the plants\u2019 roots from suffocating at the bottom of the terrarium, where a little water can collect.<\/p>\n\n\t\t<\/div>\n\t<\/div>\n<\/div><\/div><\/div>\t\t\t\t\t\t\t<\/div>\n\t\t\t\n\t\t<\/div>\n\t\t

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    Add a little\u00a0charcoal\u00a0<\/strong>to keep the compost from going stale, which in the long run causes rot that is obviously harmful to the plants. The charcoal used in aquariums works well.<\/p>\n

    How deep should the substrate be in the aquarium? If you plant the begonia \u201cin the ground\u201d, it needs enough substrate \u2013 I would say about a quarter of the height of the terrarium. If your plant is in a pot, on a cork slab or on a piece of travertine (tufa), less is enough, but some is absolutely necessary to maintain humidity.<\/p>\n

    You can \u201cplant\u201d living Sphagnum moss in the terrarium. In fact, a few strands of this moss laid on the substrate take root and then grow. As I said above, this bog moss has a remarkable antiseptic effect and keeps the terrarium permanently humid. In general, begonias love Sphagnum (not all of them, because of the acidity it creates), especially for cuttings: a begonia leaf, a rhizome or a piece of stem laid on living Sphagnum in a terrarium roots very quickly. You can also use dried Sphagnum (usually from Chile, sold in some garden centres), cut into small pieces and mixed into the substrate. Its antiseptic and humidifying effect is weaker.<\/p>\n

    Some begonias grow on limestone rocks and so need \u201ccalcium\u201d. The simplest solution is to mix\u00a0a little coral sand<\/strong>\u00a0into the substrate (available from garden centres with an aquarium section).<\/p>\n

    Growing in a terrarium: looking after the plant and the terrarium<\/h4>\n

    Setting up a plant is simple: after adding the substrate, make a round hole in the middle of the surface to take the root ball of the plant; firm it a little, and\u00a0barely water it<\/strong>\u00a0; put the lid on and place the terrarium in an \u201cideal\u201d spot\u2026 That\u2019s all! Your plant can now last a few weeks, or even a few months, without any further care.<\/p>\n

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    • Keep an eye on the humidity<\/strong> (the condensation that should form on the sides), and if it seems too low, mist with rainwater. If you think everything is too wet, ventilate.<\/li>\n
    • Keep an eye on the leaves: those that rot (this is normal, it always happens) drop off and cause the leaves they touch to rot too.<\/li>\n
    • As the plant grows, its leaves may touch the sides of the terrarium: if so, your terrarium was too small for the plant you chose!<\/li>\n
    • Likewise, when the plant flowers, the stalks sometimes rise above the leaves and touch the glass, which often makes them drop! Remove the lid and plan a larger terrarium next time\u2026<\/li>\n
    • Beware! If a fruit forms, ventilate the terrarium<\/strong>. Remember that in nature, begonias produce their fruit and then their seeds at the start of the dry season, when the plant\u2019s energy is no longer devoted to growing but to ensuring its survival by making seeds. If you keep a fruit in too damp an environment, you are almost certain to lose it. So open the terrarium or, better still, leave an opening (in the \u201cpaper lid\u201d if you used cling film) through which the stalk bearing the precious fruit can pass.<\/li>\n
    • Use fertiliser very sparingly; if the leaves turn yellow, the plant may be short of food \u2013 in that case, mist with water very lightly enriched with fertiliser. Only do this on healthy, mature plants.<\/li>\n
    • After a few months, the compost in the terrarium may dry out; if you water, the water no longer moistens the substrate (this is especially true of peat-based compost) and runs straight down the sides to the bottom of the terrarium: the plant stops growing and its roots may end up in water and suffocate! Sorry, but you will have to redo the terrarium! But as you will have taken a cutting of the treasure you were growing, you can replace the tired original plant with a more vigorous young one!<\/li>\n
    • Another common problem with terrariums: after a few months, green algae form on the glass or plastic sides. They are hard to remove \u2013 some always remain, and they come back stronger than ever! Time to redo the terrarium\u2026 Throw the compost away; do not keep it for repotting\u2026 it is \u201ctired\u201d<\/li>\n
    • Moss also often forms on the surface of the substrate, and it is hard to get rid of; note that having sphagnum \u2013 itself a moss \u2013 in the terrarium often prevents other mosses from forming\u2026<\/li>\n
    • In short, if you use terrariums, plan to\u00a0redo them completely after a year, or two at most. Use bleach to clean the containers.<\/strong><\/li>\n<\/ul>\n

      Which begonias to grow in a terrarium?<\/h4>\n

      All the small begonias from humid tropical regions can be grown in a terrarium; match the size of the container to the size of the adult plant. On the other hand, avoid growing thick-leaved begonias in a terrarium (B. conchifolia<\/em><\/strong>\u00a0for example), as these plants tolerate dry periods. Here is a non-exhaustive list of begonias to grow in a terrarium:<\/p>\n

        \n
      • Central America: bowerae \/ hydrocotylifolia \/ squarrosa \/ strigillosa<\/em><\/strong>\u00a0\/ aridicaulis \/ ludicra \/ violifolia<\/em><\/strong>,\u00a0 etc\u2026<\/li>\n
      • All the small African rhizomatous begonias, all the small tuberous begonias from Madagascar.<\/li>\n
      • Southeast Asia: all the small begonias from the Philippines, Malaysia, Sumatra, Borneo and New Guinea: decora \/ nigritarum \/ nurii \/ sudjanae \/ rajah \/ luzonensis \/ rhombicarpa \/ ionophylla \/ amphioxus<\/em><\/strong>, etc \u2026<\/li>\n
      • Mainland Asia: China, Vietnam: leprosa \/ pseudodryadis \/ augustinei \/ versicolor \/ pedatifida \/ handelii \/ chuniana<\/em><\/strong>, etc \u2026<\/li>\n
      • South America: crispula \/ lanceolata \/ olsoniae \/ depauperata \/ herbacea\u00a0<\/em><\/strong>etc \u2026<\/li>\n<\/ul>\n

        Small tuberous begonias, especially the species from Madagascar, are easy to grow in a terrarium, and this method has several advantages for these plants. The main difficulty in growing them is keeping the tuber \u2013 sometimes tiny (no more than 5 mm across) \u2013 alive when the plant goes dormant. In a terrarium under artificial light, these plants hardly go dormant at all and, better still, flower continuously! So the problem of keeping them is solved; however, it is wise to keep a few back-up cuttings, as these begonias do not rebuild their reserves as tuberous begonias usually do during dormancy, and they weaken and so live less long. On the other hand, if they do go dormant even in the good conditions described above, leave the tuber in the terrarium with the lid slightly open: it will neither rot nor dry out!<\/p>\n

        Plan larger terrariums for species such as:\u00a0chlorosticta \/ bipinnatifida \/ augustae \/ goegoensis \/ erythrogyna \/ pendula \/ borneensis \/ isoptera \/ polilloensis \/ malipoensis \/ hemsleyana\u00a0<\/em><\/strong>etc., etc\u2026<\/p>\n

        Terrariums are very useful for rooting begonia cuttings (in fact, a fallen leaf often roots spontaneously in a terrarium). A mineral water bottle cut in half is a very easy and effective way to root cuttings (see B\u00e9gofil no. 79)<\/p>\n

        Likewise, I often put a weak or sick plant in a terrarium for a few weeks, and this stay in \u201cintensive care\u201d usually does the plant a lot of good.<\/p>\n\n\t\t<\/div>\n\t<\/div>\n<\/div><\/div><\/div>\t\t\t\t\t\t\t<\/div>\n\t\t\t\n\t\t<\/div>\n\t\t

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        \n\t\t\n\t<\/div>\n<\/div><\/div><\/div><\/div>\t\t\t\t\t\t\t<\/div>\n\t\t\t\n\t\t<\/div>","protected":false},"excerpt":{"rendered":"Pourquoi cultiver un b\u00e9gonia en terrarium ? La question pourrait \u00eatre : o\u00f9 cultivez-vous vos b\u00e9gonias ? R\u00e9ponses possibles : dans mon appartement, dans une v\u00e9randa non chauff\u00e9e, dans une pi\u00e8ce \u00ab libre \u00bb de la maison, dans une serre. Pour cultiver des b\u00e9gonias dans de bonnes conditions, pour se rapprocher le plus possible des [...]","protected":false},"author":3,"featured_media":12095,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[84],"tags":[],"class_list":["post-12016","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-culture"],"_links":{"self":[{"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/posts\/12016","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/comments?post=12016"}],"version-history":[{"count":4,"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/posts\/12016\/revisions"}],"predecessor-version":[{"id":12153,"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/posts\/12016\/revisions\/12153"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/media\/12095"}],"wp:attachment":[{"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/media?parent=12016"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/categories?post=12016"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/afabego.fr\/en\/wp-json\/wp\/v2\/tags?post=12016"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}