Why you cannot keep bonsai trees indoors

Great post.

In my many years of plant keeping I have always taken them outside when appropriate and brought them back in when necessary. This consisted of mostly tropical plants. Such as aloe, Jades (crassula), some ficus and many, many Euphorbia (my potted drug of choice and what truly got me into plants outside of planted aquaria). It always seemed to me that the outdoors were where plants were the happiest. Isn’t that what everyone thinks?

I am joking above a bit. I have many years experience with “house” plants as well as submerged plant growing as I love a planted aquarium. So perhaps I’m marginally more knowledgeable than your average box store shopper. Add a little adhd to the mix and here we are.

It is only this year that my husbandry duties have finally expanded to leaving some specimen outside. I now possess deciduous pre-bonsai maple/oak sitting in pots that I am eagerly awaiting to get to next spring with to see what transpires.
 
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Maybe it's not as impossible as we once thought?
Whenever I start one of these threads, I am careful to avoid saying things like "impossible". Instead I try to say things like "99.9% of all people" :)

I know for a fact that you can keep shallow water tropical reef corals in aquariums indoors. These corals are photosynthetic and require spectral lighting intensities much higher than any bonsai tree. However they also require very specific, isolated setups that often require an investment in the thousands of dollars.

Commercial plant growing setups are available for growing vegetables and other produce indoors, some of which include motorized rails (to prevent shadowing) and very sophisticated timing and spectral intensity programs to trigger flowering and fruiting. However, once again they are expensive, and space-requiring. With the advent of LED lighting, you can get quite good full spectrum plant grow lights today that don't break the bank that don't have the features or performance of commercial setups, but are adequate for keeping some plants indoors. So it isn't uniformly "impossible". Just highly highly unlikely unless you know what you are doing, have the right plant, and have the right setup.

What I am trying to suggest is that bonsai are not houseplants, and that for people to think they can bring one home and put it in a window and they will be fine, they are in for a rude awakening. Perhaps it would be best to start with a list of requirements for all bonsai:

(1) Good soil (easy to provide), good fertilization (easy to provide)
(2) Good water (less easy to provide, depending on your water source)
(3) Full spectrum lighting (almost impossible to provide without supplementation)
(4) Air movement (easy to provide, however many people don't like fans constantly running in their homes)
(5) High humidity (most people feel uncomfortable in humidity levels that bonsai trees prefer)
(6) Seasonal change (very difficult, if not impossible to provide indoors)
(7) Pollination (very difficult to provide indoors)

Taking this list into consideration, you can rank order bonsai trees from "somewhat suitable for indoor cultivation" to "almost impossible for indoor cultivation". Sure you can grow a Japanese black pine indoors with enough supplemental lighting. Can you say the same for a Japanese white pine? For a Japanese maple? There are many quite advanced bonsai practitioners who know that even in the best gardens, you can only work with what Mother Nature gives you. Can you grow a bristlecone pine outdoors in SoCal? No - not cold enough. Can you grow a ficus outdoors in Maine? No - too cold. So if we can't do certain things in nature, it stands to reason we can't do certain things indoors - without significant supplementation/artificial set-ups.

I happen to like deciduous hollies and princess persimmons. I also know both plants are sexually dioecious - that there are male and female individuals - and that only female plants fruit and without males (and pollination) you will typically not get fruit on your trees. Are you going to keep these trees indoors successfully - simulating the seasons as well as artificially triggering flowering and manually pollinating? It is possible. Is it practical? Is it the rule - or is it the exception? However I can guarantee you that at some bonsai show somewhere in this country, someone will walk in, see a beautiful persimmon bonsai, buy it, and try to keep it indoors.

We always like to tear into "the rules" on this site... but the rules are very important because so many people start in bonsai trying to work with the exceptions to rules - and don't understand why the rules exist. They fail... and then they quit... and bonsai gets the reputation as being "difficult" when in fact it is relatively simple as long as you provide what Mother Nature provides. Mother Nature doesn't generally hang out in a New York City condo.
 
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In addition to what @Bonsai Nut stated above. I have a few tropical trees, ficus and Brazilian rain trees that would never survive outside here during winter. So I bring them inside from October to May or June and put them under several bulbs of full spectrum lighting.

Do they survive, yes, they even grow under these conditions but after doing this for about 10 years with them now, I can say they are always much happier once I put them back outside for the summer. They put on much more growth in the summer outside, partly because it's summer and their growing season but I do believe that it is also due to them just being outside in real sun light.

I have kept them inside for up to 18 months and they "did fine" but I'm not sure how long they would be able to thrive that way
 
An atrium with no roof and full sun is outdoors for all purposes, especially in zone 10a. My first bonsai is a Natal plum, I've had it since 1974. The only reason it survived my decades of ignorance is that I put it outside every year as soon as the weather was warm enough.
 
I think a better way to say this is "It is near impossible for someone new to horticulture to learn what they need to know, to be able to grow bonsai indoors, in less than one year".

I've been growing orchids under lights, for over 45 years. Most of this time my collection was over 1000 plants. Growing sub-tropical and tropical trees under lights is do-able after the long internship I've served raising orchids. I will say "summer outdoors" makes life much easier. These days, I'm retired and downsizing. I only have 5 or so trees that are subtropicals or tropicals. Only one Ficus, A fun Bursera, love the fragrance, not much for looks, a new gardenia and a few others.

I would say, it would be impossible for a beginner to get the horticulture down without major mortalities the first 5 years or so. But if you know the horticulture from other under lights plant hobbies, just getting the light intensities up and air movement up to prevent heat gain in the leaves, it is possible to do some trees well.
 
Hello.

right now I'm planning to buy my first indoor tree.
It will be Jabuticaba or Serissa.
I love maples, but that wouldn't work...

Did you see the title of this thread? There's no such thing as an indoor bonsai tree. There are only tropicals that need to be kept out of the cold during the winter. Unless you live in a greenhouse, your plants will not thrive in your house.
 
Did you see the title of this thread? There's no such thing as an indoor bonsai tree. There are only tropicals that need to be kept out of the cold during the winter. Unless you live in a greenhouse, your plants will not thrive in your house.
Of course I read it. I live in Europe, it's cold here now. 😅
 
Of course I read it. I live in Europe, it's cold here now. 😅

Do yourself a favor and start with a ficus. Ficus microcarpa is a great teacher. You'll see all of your bonsai techniques take effect very rapidly, and that kind of prompt feedback is rare. It's also hard to kill.
 
As already stated multiple times, the tropicals grow much more vigorously out side in summer. I do have half a dozen smaller bonsai that have been inside now with no exposure at all to the outside, since they were started as cuttings. These are in the range of six to ten years old from cuttings. Would they do better outside? Of course. But they are babied and enjoyed every single day of the year and can sometimes go up to two or even three days between watering. If these were outside, they would likely require watering twice a day. I also have about a dozen ficus that started out indoors and were kept up to eight years and then moved outside to develop into larger bonsai. I enjoy these indoors for 7 months of the year.
 
I got a ficus for 7 years now still alive.
During fall/winter its inside on the window sil above a radiator and im not joking.
I do however mist the leaves every day but it even grows some while inside.
Rest of the year its outside growing way better but i guess that makes it strong and pull trough winter inside?
Maybe a big difference that after these year i know my plant also the "new" people have a bad start by buying a weak plant and then keep it inside without realy knowing nothing about horticulture and by the time they try and figure out the basic care the plant is either dead or nearly and then the wrong advice comes in like repot it etc and they kill it.
The people realy interested in the hobby will try again others might Just give up after that.

I recently recieved a sargeretia theezans mallsai from a friend she bought it in a nice waterfall pot she was afraid it died so it ended up at my house now i will have to do my best to keep it alive and research the species... good for me after 8 years i know where to search and know the basics and am able to filter bad info, i wil never say im a professional but ive had some years now and think i got a decent idea of what im doing but maybe this sargeretia going to chalenge me haha
 
Hello.

right now I'm planning to buy my first indoor tree.
It will be Jabuticaba or Serissa.
I love maples, but that wouldn't work...

As others have said, these 2 species are not the "best" meaning easiest to grow indoors, but they are not the worst. Serissa is often recommended as a beginner species for bonsai, though most of us find it tricky. Serissa will either thrive for you or just die for you, even if you think you know what you are doing. I kept a couple going for a number of years, then I repotted them and moved them to the bank of lights opposite their original location. I thought the same conditions. They quickly withered away. I never figured out why.

Jaboticaba has some really nice bark and small leaves for a tropical fruit tree. I was never able to keep one going more than one season. They just did not adapt to my under lights set up. I'm sure others have success. But myself, I had trouble with it.

I can grow trees under lights, had a pomegranate for over 40 years which wintered under lights. Bursera, and several others do fine too.
 
I guess next would be either humidity or airflow. Indoor air is dry and stale.
I've found that growing plants grouped under a light, especially in enclosed conditions such as a plant tent, provides them with sufficient humidity-- enough to let ficus and Schefflera grow aerial roots.
 
Well lets start with light. Do you ever have to wear sunglasses in your living room? The only places where I've seen somewhat successful indoor growing are spaces designed for it, and I needed sunglasses to work in them. Light intensity and the spectrum available to trees are found outside, not in. Your can somewhat replicate that with a bunch of effort and money but you'll create a space you can't comfortably live in.
OMG...so true. I grow high light demanding orchids under lights. And after changing them around the other day, my eyes and head hurt. Next time I will turn the lights off or wear sunglasses. But, all my trees are outdoor.
 
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