It’s easy for people (myself included) to think a terrarium just needs the right plants and a bit of water and it’ll be set for life. But one question that I don’t see covered too much in terrarium building tutorials is where do you actually place your terrarium at home? Turns out, the answer to the question of terrarium placement is more important than you might think.
The ideal placement of your terrarium should be within 5 feet of a window. South-facing windows will be best for cacti and succulents because the south side receives the most amount of sunlight. Terrarium plants that prefer indirect sunlight will be best placed near a south or west-facing window.
If you follow those guidelines, your terrarium should be good to go for the most part. In the rest of this post, I’ll get into the details of where those guidelines come from and how you can take them to your particular setup.
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The best place to put your terrarium at home is near a window
Terrarium placement is an important, yet often neglected aspect of caring for a terrarium. Here’s why: where you place your terrarium has a major influence on the amount of light it will be receiving. As you might expect, the places that have the most light are your windows.
Why your terrarium should be near a window
While it might look like your room has plenty of light all over the place, the intensity of light actually starts to drop off considerably once you start moving even a few feet away from the window.
This intensity dropoff isn’t linearly proportional to distance. It’s more like an inverse exponential. That means most of the light intensity dropoff happens in the first few feet of movement away from the window, then it almost levels off at a steady, lower intensity level.
If none of that made sense to you, the chart below gives a rough visual of what’s going on:
If you want to verify that, you can get a light meter to measure the lux (a unit of light intensity) as you move away from one of your windows.
That’s why it’s really important for you to place your terrarium in close proximity to a nearby window. If you’re putting your terrarium on a shelf somewhere or on a dining room table away from any windows, there’s a high chance the levels of light might not be as sufficient for it, especially if you are growing succulents.
How far your terrarium should be from a window
The chart about light is nice and all, but what does that tell you about how far to place your terrarium from a window? To get some advice from some terrarium professionals, I reached out to some of the gardening stores in my area.
Here’s what City People’s Garden Store had to say about terrarium placement:
There are many different places you could put your terrarium, and the right answer varies for different people and the plants used in your terrarium. For example, at my home I have a low-light terrarium that sits about 6 feet away from a west facing window. Because the lid of the container is opaque and not glass, not much light reaches these plants, but they’ve been doing just fine!
Parker, City People’s Garden Store
So there’s a few key points that Parker brought up here.
First of all, the exact placement will depend on what plants you have in your terrarium. In case you didn’t know this already, some plants prefer bright, direct light while others prefer less intense, indirect light.
For a closed terrarium, most likely (If you’ve chosen your plants wisely) you will have plants that enjoy high humidity and indirect light. This means that they will probably do best at a reasonable distance away from a window (a few feet or more), but not too far.
For an open terrarium with plants that prefer bright, direct light, you will probably want to place it within a few feet from a window.
In either case, I would be cautious about placing your terrarium directly on the windowsill. Many plants will not be able to tolerate full-intensity sunlight because it can cause them to get stressed. And that stress will show if pushed too far.
Too much sunlight can also cause your terrarium to overheat (like a mini-greenhouse effect), which can be deadly for your plants. That’s especially true for terrariums in glass containers because the glass can magnify the light rays and potentially burn your plants.
The other point that Parker brought up is the opacity of your container. Depending on the material of your container (glass or plastic), that can affect how much light is getting into your terrarium.
If you’re using something opaque like plastic, you may want to move your terrarium a bit closer to a window than if you were using glass. That’s going to compensate for the reduced sunlight passing through your container and reaching your plants.
If you’re using glass, you may be able to move your plant a little bit further from the window.
In either case, all you’re doing is adding a slight correction factor to how far you’re going to place your terrarium from a window.
Why the direction your window is facing matters for your plants
The last point Parker brought up is the direction your window is facing.
Tassy from Glasswing (another local gardening store) also brought that up:
Cacti/succulents prefer direct sunlight from a south or west-facing window. Foliage plants prefer bright, indirect light or direct morning sun. All plants should be placed within 5′ of a window.
Tassy, Glasswing
So here’s the deal with the direction of your windows: each window does not receive the same amount of light throughout the day. Because the Earth is on a slight tilt, the sun will actually shine more on the south side than the north side in the northern hemisphere.
This table gives a breakdown of which directions give what kind of light:
| Direction | Sunlight Type | Best for |
|---|---|---|
| North | Least amount of sunlight, never direct | Closed Terrariums |
| South | Most amount of light, bright, direct sunlight within 2-3 feet | Open Terrariums |
| East | Morning sunlight | Closed Terrariums |
| West | Evening sunlight | Open Terrariums |
What you’ll see in the table is that the south side receives the most light. That’s going to be the best place to place your terrarium if you have plants that are tolerant of high levels of bright, direct light. Otherwise, you may want to move your plants a little bit further from the south window than you would otherwise.
The north window is going to be best for closed terrariums with foliage plants that like shadier, indirect light. You may be able to get away with placing your terrariums directly on north-facing window sills.
In between those two extremes, you have the east and west facing windows.
The sun rises in the east and sets in the west. This means the east side will receive the less intense, morning light rays. The West side will receive the stronger, more intense afternoon and evening light rays.
What this means is that closed terrariums with plants that prefer indirect light will do better on the east side.
Open terrariums with direct sunlight loving plants will probably do better near west facing windows.
Where you should definitely not place your terrarium
Where there are places you should place your terrarium, there are also places where you should definitely not place your terrarium.
Just to name a few:
- Next to a heater or radiator
- Tucked away on a bookshelf
- Near a fireplace (if the fireplace is being used)
- Outdoors
- In your car
- Next to your refrigerator
- Next to your high power computer
- Next to lamps (unless it’s a grow lamp)
Mainly what you want to avoid is placing your terrarium where it’s going to experience high temperatures or insufficient sunlight.
Many plants will not be tolerant of high temperatures (90F+), especially moss. Foliage plants generally prefer growing in about room temperature (70-80F).
For that reason, you’re going to want to avoid placing your terrarium near a heating vent, radiators, fireplaces, stoves, and refrigerators. All of those are going to give off heat which your plants are probably not going to enjoy.
Same thing goes for cold temperatures, although I think that’s less likely to be a problem for you if you’re living with indoor heating. Just don’t place your terrarium in the freezer and you should be good to go. Most plants will be comfortable with temperatures down to about 50F.
You will also want to be cautious about placing your plants somewhere that looks shady. Our human eyes have a hard time telling what exactly is enough light for a plant. But if you refer to the graph earlier in this article, it’s best not to stray too far from a nearby window.
How terrarium grow lights work
So it turns out there’s an exception to always trying to place your terrarium near a window. If you are using grow lights, you can place your terrarium anywhere you want.
Here’s what Parker from City People’s Garden Store had to say about grow lights:
You may have a large, 10 gallon terrarium, however, with its own grow lights and water recycling system. And those can truthfully live anywhere. When you have a grow light inside your terrarium, be mindful of the plants you choose. Remember, not every plant likes to live in direct bright light!
Parker, City People’s Garden Store
Grow lights can be a great option if your location doesn’t give enough sunlight to support growing plants of your choosing. They can also be great if it’s inconvenient to place your terrarium near a window or you just want to dedicate a single storage room for growing terrariums.
There are a few different types of grow lights that come in several sizes, light wavelengths, and wattage, but essentially they function the same: they generate light to be absorbed by your plants for photosynthesis.
This means you won’t have to rely on sunlight to enable your plants to perform photosynthesis. You can just do it yourself artificially.
They might even make it a little bit easier because some of them allow you to set the light intensity yourself. No need to guess the optimal distance from a window.
Just don’t set the light too close to your plants.
Don’t leave grow lamps on 24/7
The one caution I would give you if you’re going to use a grow lamp is you don’t want to leave it on all the time (in most cases). It’s much more preferable to turn the light off at nights/evenings.
Plants in nature are not accustomed to being exposed to sunlight 24/7. It’s more natural to give them a break from the sun every night to mimic day and night cycles.
When plants are exposed to light 24/7, that forces them to perform photosynthesis nonstop which can stress them out. Essentially what’s happening is they’re using up all their resources to perform photosynthesis all day with no breaks, leaving nothing left for other necessary plant functions.
Most grow lamps will allow you to set on and off cycles at a defined interval. So that shouldn’t be too much of an issue. Otherwise, you can always manually shut it off before you go to sleep.
Other common terrarium mistakes
Besides the placement of your terrarium, there are a handful of other common mistakes that you will want to avoid with your terrarium.
Over watering your terrarium
A lot of beginning gardeners are a bit overzealous when it comes to watering their plants. Plants need water, so I should give them a whole bunch of it right?
It turns out, too much water is harmful for plants. When you give your plants too much water, you prevent them from absorbing any oxygen through their roots.
That causes problems with root rot, where the roots start to suffocate and die off. That’s going to leave an unpleasant order and cause your plants to not look so healthy.
It can also encourage mold growth, which no one wants to see in their terrarium.
If you want to learn more about that, you can check out this article where I discuss over-watering in more detail.
Choosing the wrong plants
Choosing plants that are not suitable is another mistake that many beginners will make.
It turns out, not any plant can just be thrown into a terrarium and thrive.
This is especially common with succulents. Succulents do not do well in closed terrariums and will generally not do well when spaced closely together with other plants or succulents.
This also happens when plants with extremely different light, humidity, or watering requirements are smushed together in a terrarium.
If you have plans with a whole bunch of different requirements in a terrarium, it’s going to be next to impossible to make them all happy at the same time. That’s why you want to choose plants that have pretty much the same requirements and preferred living conditions.
If you want to learn why, I explain why in another article that you can check out here.
Not doing any maintenance on your terrarium
This one isn’t quite a mistake per se, but it’s definitely not ideal for your terrarium.
Common maintenance items include:
- Cleaning your terrarium container
- Removing dying/decaying plant parts
- Pruning your plants
Technically, you could get away with never performing any maintenance on your terrarium. It’s been done before plenty of times.
However, that increases the risk of your terrarium running into issues like unhealthy or overgrown plants. It also might mean your terrarium might not last as long as it’s fully capable of.
I have another post that goes into terrarium maintenance that you can check out here to learn more about that.
That’s pretty much all I have in this post. Just a quick recap: place your terrarium near a window. That’s going to be the best place for your terrarium.
If you want to learn more about terrariums, check out some of the articles linked below to learn more.
Big thanks to City People’s Garden Store and Glasswing for sharing their knowledge on this topic! Be sure to check them out if you’re ever in Seattle.