If you love indoor cacti and succulents, then a terrarium is the perfect way to bring them into your home. In fact, one of the most beautiful and easy terrariums you can make is a cactus terrarium. Cactus plants are easy to grow and maintain, making them a great starter plant for people who want to try their hand at gardening. Succulents are also quite simple once they have been planted in soil or sand. Terrariums also make great gifts for loved ones, so if you’re looking for DIY gift ideas, a cactus terrarium would be perfect for that special someone.
So, how do you make a cactus terrarium? It all starts with getting the right materials like ideal containers (jars, vases or glass balls), gravel, cactus soil mix, peat, moss, and finding the right cactus plants. Make your layering to allow for perfect drainage and plant your preferred cactus plant. You can then include decorations like stones, colored pebbles or marbles. Take care of your terrarium by focusing on proper lighting, watering and humidity levels.
It can be very easy to get tempted into believing that cactus can do well in any traditional terrarium. Nothing could be further from the truth. This guide will take you through modern terrarium designs and how best you can maximize the potential of your spiky companions in a terrarium.
Factors to Consider When Making Your Cactus Terrarium
Humidity is very important when it comes to cactus and succulents. Many desert plants come from hot and dry climates, so you will need a terrarium that can mimic these conditions for your plant to thrive. If the humidity is too low in the container, then water loss through transpiration will not be sufficient enough for them to photosynthesize and stay healthy. If the humidity is too high, then fungal diseases can become an issue. Even so, too much humidity is better than not enough – provided you have the correct airflow and drainage in place to handle this excess water content.
Humidity levels will depend on your home’s climate and the size of the terrarium that you choose for your plant or plants. You may need to get a hygrometer to measure the humidity levels in your terrarium more accurately.
If you want to use a closed terrarium, then some special considerations need to be considered regarding humidity levels. The most common problem with closed terrariums is the fact that they tend to get too humid in certain conditions and not enough moisture during dry spells.
The plants will need airflow through the container to get enough carbon dioxide for photosynthesis and expel any excess oxygen from their system. Without this, you may end up with an unhealthy plant even though there is sufficient water in the container.
Airflow is also important because it helps to remove excess humidity from the container. If you plan to use a closed terrarium, this is even more crucial as such containers can develop too much moisture and become toxic for your plants if not enough air flows through them.
When you have your cactus terrarium completely sealed, it’s important that the soil can retain sufficient moisture for the plant or plants inside. If this isn’t possible due to limited drainage, make sure to have some pebbles atop the substrate so that water can be wicked away from the soil and absorbed by these rocks.
For better results, put a saucer under the container and add water to this instead. This way, you can be sure that your plant will get enough moisture while also ensuring that too much won’t build up in the terrarium. Remember, the pebbles will only work if they have holes for water to escape from.
Lack of drainage can be a death sentence for your cactus plants, especially if you are using a closed terrarium where humidity levels get too high during certain periods. When choosing substrate or gravel to put in your container, make sure that it is large enough to support the plant and allow water to escape.
Without proper drainage, you can end up with a toxic terrarium that will eventually kill your cactus or succulent plants. If you are using sand as your substrate, then it’s best to mix some charcoal into this for better results. There are different types of sand available, so choose one that is more coarse in texture and has a dark color.
Terrarium Container Options
Cactus plants can be very rewarding to grow indoors, although there are some things you need to take into account when making your cactus terrarium design. You will have better success if you choose the right container for your plant or plants, but also ensure it has proper drainage so that the soil doesn’t get waterlogged.
Storage jars: You can use a range of different storage containers to make closed terrariums, such as large mason jars or even clean pickle jars if you want an extra challenge in making your indoor cactus garden design.
Teardrop glass for making hanging terrariums: Teardrop glass for making hanging terrariums can be a beautiful addition to your home if you have the right kind of cactus plants.
Globe vase with metal stand: Globe vase with a metal stand is another great option if you want a creative way to showcase your cactus garden indoors.
Glass orbs for hanging terrariums: Glass orbs for hanging terrariums make a great choice if you want to create your own unique cactus garden design.
Large archway terrarium: Large archway terrarium is another creative option that lets you grow more than one type of succulent or desert plant together in the same container.
Small jewel box terrarium: Small jewel box terrarium is a great option if you want to create something small and simple for your cactus garden design.
Classic (Closed) Terrariums Vs. Modern Terrarium Designs
The classic (closed) terrariums have hitherto been the most popular type of terrarium designs. However, modern terrariums are fast catching up with their popularity. Closed-type terrariums feature a clear glass or plastic container sealed at the top to hold in moisture and encourage plant growth. While this type of terrarium makes it easier to maintain, modern designs are better suited for cacti and succulents as they do not require high humidity levels.
Modern closed-style cacti containers can be made using large jars like the ones used for pickles. These large jars allow enough space between the plants and provide sufficient air circulation to prevent rot or mold. Plus, they look great on a tabletop as well. Apart from the low humidity levels, the modern designs work best for cacti because the plants do not require a lot of light to survive. This means there is no need for the terrarium to have a transparent top that lets in more sunlight, resulting in overheating or even death due to exposure.
Suitable Terrarium Cactus Plants
Most types of cacti can be used for terrariums. However, certain species have been found to work best in these types of containers, and they include the following:
- Christmas cactus (Schlumbergera) – The Christmas cactus is an ideal candidate for the terrarium, thanks to its low-water requirements. It will thrive in a high humidity environment and produce beautiful blooms too. The plant is not very picky about light levels either, so you can place it on your window sill or tabletop without worrying about heat damage.
- Hen & chicks (Echeveria) – This type of succulent plant is characterized by thick, fleshy leaves that grow in rosettes. The plant is native to Mexico and South America and does not need a lot of light or water to survive. It will even thrive when kept dry for prolonged periods, making it ideal for infrequently watered terrariums.
- Desert rose (Adenium) – This plant is a flowering succulent that grows up to five feet tall in its natural habitat. However, when grown indoors, it can be kept much smaller and will even flower too. Desert rose needs high humidity levels to grow well, making them ideal for terrariums.
- Jade plant (Crassula) – This type of succulent is native to South Africa and are characterized by thick, fleshy stems which store water. The plant does not require much light or water when grown indoors, making them perfect for terrariums where they can be kept in a dark corner with infrequent watering cycles.
- Rhipsalis (Mistletoe cactus) – The Rhipsalis is a tropical cactus native to South and Central America. It does not require much light but will thrive in the high humidity environment of a terrarium.
- Hylocereus (Night-blooming cereus) – This type of cacti is native to Central and South America. It features long, succulent stems with many spines along the whole length. The plant will grow up to a height of twelve feet when grown outdoors but can be kept much smaller in a terrarium where it does not require as much light or water as other types of plants.
Steps To Set Up Your Terrarium:
Step One: Assembly of Materials
The first step towards setting up your own DIY cacti terrarium is gathering all the materials you need. For this, you will require the following:
- An open jar or glass container – This should be around one gallon in size and can either have a wide opening or an elongated neck. This ensures good airflow and less humidity in the terrarium environment.
- Pea gravel – Half to one pound of pea gravel is required for the bottom layer in your cactus container and provides a gritty surface that prevents plant roots from rotting while keeping them dry enough to prevent fungus growth.
- Sphagnum moss – This is available as a peat-free alternative that does not contain any spores of the fungus that causes sphagotricha. The inclusion of this type will help to retain moisture for longer periods without attracting fungal growth.
- Sphagnum peat – The sphagnum peat is perfect for the top layer where you will be planting your cacti and provides a high humidity environment. It also absorbs moisture, making it great at keeping the terrarium moist without overdoing things.
- Potting soil – you will need a good quality potting mix with equal parts of peat moss and perlite or pumice rock for the best results. Cacti grow well in fast-draining soils, so do not use regular heavy garden soil that retains moisture too long, resulting in rot.
- Cactus or succulent plants – You can grow any type of cacti in your terrarium, but some do well when grown indoors, as already discussed. Succulents are also an option and can be chosen according to the enclosure you have chosen.
Step Two: Setting soil in the layers
The next step is mixing your soil components before filling up each layer of your terrarium appropriately. It would help if you filled up the jar three-quarters full with pea gravel, then added a thin layer of sphagnum moss, followed by the potting soil.
When doing your gravel and soil layering, consider root aeration as cacti have relatively shallow roots.
Once you are done with your layering, moisten the soil lightly and press it down to compact it. Do not use excess water as this will make the substrate too heavy for plants to root in easily. The best way to do your layers is in three steps: gravel, moss and soil.
An alternate method with plant roots is to add a layer of pebbles at the bottom for drainage before adding your cacti plants with their root balls above this base level. Then add more sphagnum moss on top, followed by moistened potting mix or perlite for the soil layer.
Step Three: Adding Cactus & Decorations
Now that your terrarium is set up with an appropriate growing medium for the plants, it is time to add your cacti and other decorative items. You can use plastic or clay pots for this purpose as both are opaque enough that the plants do not need direct sunlight, allowing them to thrive in a terrarium environment.
If you wish to plant succulents instead of erect cacti, consider using only one type per container to avoid overcrowding.
You can add a layer of gravel over the soil surface before planting your cacti which will help with drainage but do not use too much or risk fungal growth from excess humidity. You also need to ensure no water is trapped between layers by allowing adequate airflow and using materials like stones and gravel to prevent pooling.
Cacti look great when planted alone in a container, but you can add other items like moss or small pebbles if you wish. Just make sure that these decorative items do not interfere with the root system of your cactus by creating pools for water to form and cause rot. Remember to keep them away from the top layer, which is where you will be planting your cactus.
Caring For Your Terrarium
Planting your cacti is just the first step to your terrarium. You also need to take care of them by providing the proper condition for growth.
Unlike the tropical cactus, your terrarium cactus needs special attention, especially in terms of watering. You need to make sure that they are not overwatered or watered too often, as this can cause rot and other problems with your plants.
The best way to water a terrarium is by misting the entire surface once every week. This should be enough to keep them moist, but if you wish, you can add a little bit of water to the soil surface after misting.
You also need to consider lighting requirements for your cacti plant if they are not placed outside in direct sunlight. They should get bright light, but no direct exposure as this will cause them to rot and die quickly. If you have a closed terrarium with poor ventilation, then you need to make sure that your cacti are getting enough indirect light for them to photosynthesize.
Dealing with Mold
Mold in cactus is usually caused by excess moisture in the terrarium, which can be prevented by avoiding pooling water and ensuring good airflow. You should also watch out for fungus gnats if you have a dirty container, as these can cause a lot of damage to your cacti.
Other types of mold may affect the soil surface, so it is important that you monitor this regularly and change out old substrate if necessary. It should be noted that most kinds of mold cannot grow in soil with good drainage.
Making a cactus terrarium shouldn’t be a hassle if you understand the basics of how to create the right conditions for your plants. Remember to always start with a clean container, add the right materials for your plants to grow in and ensure proper ventilation. You can mix this up by adding decorative items that don’t need much sunlight if you wish but overall, just make sure that everything is balanced out well.