How to make your own terrarium

Updated: Sep 16, 2019

Making your own terrarium isn't as difficult as you might think. Here's a guide to help you on your way.



1. Choose a container suitable for your plants


If you've got an old demi-john or bell jar hanging around then these are perfect for making enclosed terrariums. Maybe you've got an old vase you don't use or a large gin glass that's redundant. Anything is possible with a little imagination. Be creative with your container and you can create something unique and special. Just make sure that it's watertight, crack free, tall enough to create layers for your plants and clear so you can see your handiwork.


Some tips for choosing the right container:


  1. Don't plant succulents or cacti in high sided glass containers unless they sit right at the top if you are placing your terrarium in sun. The plants will scorch and die. The same goes for carnivorous plants unless you are keeping the soil section of the container in shade, i.e. under a windowsill or on a dining table that's not in full sun. If you are planting your succulents in a standard terrarium like the one in the picture at the top of this page make sure you keep it away from windows. Bright sun and drafts will have the same affect even if the container has a large opening.

  2. Make sure your container is going to be big enough to cope with a growing plant. Ferns, for instance can grow quite large, and planting one in a small container won't do. Always check your plant growth height on the label as it may be small when you plant it but might not be in a years time!


2. Select which plants you want to use


Once you've selected your container it's time to consider plants. You could of course pick your plants first but make sure your container is suitable for them.


Choosing the right plant for your terrarium is one of the most important things to get right. Get it wrong and the plant will most likely die. In order to create the perfect, long lasting terrarium consider the following

  1. Where will my terrarium be situated - full sun, bright light but not full sun, shade, warm or cool conditions?

  2. How much care do I want to give my terrarium - If you're a forgetful plant owner then choosing a thirsty plant might not be the best! Consider using succulents instead, or creating a closed terrarium which relies on condensation to self regulate. If you remember to water your plants then the world is your oyster!

  3. How big will the plants get? Make sure your chosen plants won't turn into giants in a years time.

  4. If you are planting more than one plant it's vital that they can survive in the same soil type. So for instance, you can't plant a fern and a succulent in the same soil because one of them will eventually die either from rot or dehydration.

  5. Lastly, think about how plants look together. You'd be amazed at the difference picking complimentary plants has on the aesthetics of a terrarium. Putting succulents in a container that are all the same colour will most likely look nice but a little uninspiring, but pick succulents in different colours will look amazing!


3. Select the correct soil and substrates


With your container and plants selected you need to look at the soil and substrates. By substrates I mean the stones and filter layers.


Soil with drainage included is good for plants like ferns and houseplants

Stones are used as the first layer and these provide a drainage 'tank' for water to run into so that the soil doesn't become waterlogged. This layer is really important so don't leave it out. The only exception to this rule is if you are planting succulents and cacti. These plant groups need little water and specific soil so the risk of them drowning is unlikely unless you are overzealous with your watering can. Because your stones will be visible you might like to choose decorative stones rather than bog standard shingle.


white stones look beautiful with dark tones in the soil and plants like ferns

The filter layer is next and usually this is made of either sphagnum moss or fine wire mesh. And in a closed terrarium this would include an additional layer of charcoal which provides a natural bacterial filter for the water. Sphagnum moss can be purchased from most garden centres in small bags and usually costs between £4 and £6. Charcoal is available in my shop and fine wire mesh, if you choose this method, can be purchased online. or in most DIY stores.


charcoal is really important in an enclosed terrarium

Lastly the soil. This is just as important as picking the right plant. Put succulents in normal compost and they will eventually rot. Put a fern in a gritty compost and it will dry out to quick and most likely die. You can buy the correct soil through my shop but generally succulents and cacti require a light, gritty soil which is free draining. Ferns suitable for indoor planting are generally good in most composts mixed with a little grit for drainage. Some ferns do prefer peat so check the plant label before planting. Houseplants are generally good in compost which is available through my shop.


use a gritty or sandy soil mix for succulents and cacti

If you ensure you choose the right soil for the job your plants should be very happy.


4. Get planting!


Now that you have everything you need gather it together and follow these steps to plant your own mini garden.


Step 1. Make sure your vessel is scrupulously clean so that bacteria doesn't contaminate your plants and soil. Once its clean add your chosen drainage to the bottom. It's easiest to do this with small necked vessels like bottles with a funnel. You can make this using rolled up paper or a cardboard tube.


Step 2. Add your filter layer. If your vessel is going to be sealed with a lid then you MUST add charcoal at this stage. This prevents bacteria from growing by filtering the air and water in the terrarium. If your terrarium is open then you don't have to add charcoal but it doesn't hurt to anyway. When your charcoal is added add your next layer. This would usually be something like sphagnum moss. The purpose of this is to separate your soil from your filters and adds another layer of drainage. Don't leave this layer out. Some people use very fine mesh instead and that's ok too.


Step 3. Add the appropriate soil. Again, if you are using a narrow necked vessel use the funnel method. If you need to level your soil you can either gently swirl the vessel around until it levels, or use a long stick with a bottle top glued to the end to pad the soil down.


Remember:


Gritty free draining soil for succulents and cacti - and only plant these in a container with a large opening so that air can circulate. And don't plant them in a bottle. Try to use something where they are close to the top or they will scorch in hot glass during the summer if in the sun or rot from condensation. You can buy soil here


Ferns and other plants can be planted in standard compost or my own mix available here.



Step 4. Now its time to add your plants. Decide where you want each plant to sit first. This will depend on whether your are having just plants or if you are including any objects like stones or statues.

a) Using something you can dig a hole with (here they've used a long handled spoon but you may need to make something yourself) make a well in the soil big enough to take the roots of your chosen plant.




Now here's the tricky part! Getting your plants inside the terrarium can be difficult especially if your container looks like the one in the picture.


b) Firstly, try to remove as much soil as possible from the roots system. Ideally you should be planting just the roots. The easiest way to do this is remove as much soil as you can by hand and then dunk the remaining soil in water, give it a little swish around and that should remove a good quantity of what's left.

Remove as much soil as you can from the roots

c) Once the soil is removed you need to get it in to the terrarium. Now, if you're container is narrow necked the best way to do this is to wrap your plant in either a bit of newspaper or slot it inside a loo roll like below. Leave the roots exposed and only cover the leaves as these are likely to get damaged.

wrap your plant in a loo roll or paper ready to plant

d) Very gently push your plant in the protective tube into the neck of the container. If your container doesn't have a neck then you can simply remove the soil and pop your plant straight in without wrapping it in a tube.


e) When you reach the hole in the soil drop your plants roots into the hole. You might find you need a long pair of tweezers if your container is large. Using your planting tool gently but firmly push the roots into the hole until they are firmed in. Now cover the roots with soil and firm this down. Repeat until all of your plants are safely in place.


f) Now you can remove your tubes. Again, this is easier with a pair of long tweezers depending on your container.


Step 5. Add any other decor your wish. Just bear in mind that untreated wood will rot after a time when its in a container so use varnished or treated wood only. Also don't use anything painted or dyed as this will run into the soil when it gets wet.


little people from the inside of one of my terrariums

Step 6. Give it a water. Don't drench it, just water it enough that the soil becomes wet not saturated.


Step 7. If your container got dirty inside give it a clean.



Step 8. Pick an appropriate spot for your new garden! For enclosed terrariums keep out of direct sunlight or the plants will bake. The same goes for plants encased in glass even if it's an open container.


Now keep an eye on the water levels and water according to the plants needs. And don't forget to feed your plants too. A terrarium is no different to a plant in a pot (unless its sealed, in which case you shouldn't need to water it at all after its first watering but should feed it during the growing season).


Sit back and appreciate your creation and enjoy your new indoor garden.


Got any questions on this subject? Drop me a line and I'll be happy to help. hello@gardensinglass.co.uk



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