Quick answer: To keep a terrarium out of reach of cats, mount it on a sturdy pine plywood shelf well above jumping and climbing routes, choose a closed glass container with a lid, and plant only species listed as non-toxic to cats by the ASPCA, such as nerve plant or polka dot plant. Never include lilies, even as cut stems nearby.
Spring is when many people refresh their homes with new greenery, and terrariums are a popular choice for small spaces like a dining nook. For cat owners, the challenge is that glass, soil and small plants all invite curious paws. In a multi-cat home, one bold climber can undo the best intentions.
This guide shows how to build a simple pine plywood shelf, pick a container that stays shut, and plant species that are safe if nibbled. Our cat-safe plants DIY hub links to more indoor garden ideas.
Why Terrariums Attract Cats
A terrarium combines movement, scent and texture in one small object. Leaves brush the glass, condensation forms and the soil smells of earth. Cats sniff, paw and sometimes try to dig. Open designs also give access to small stones and moss that can be swallowed.
In homes with several cats, one cat may climb while others watch and copy. Placement has to account for the most agile cat, not the average one.
A terrarium also tends to sit in a room where people gather and eat, which is exactly where cats like to be. Rather than banning the cats from the dining nook, the aim is to make the plants simply unreachable while the cats keep their place at family meals.
Plants for a Terrarium Out of Reach
Even with a lid and a high shelf, choose plants that are safe in case a cat gets to them. The ASPCA lists the nerve plant (Fittonia) as non-toxic to cats, and its small patterned leaves suit closed terrariums. The ASPCA also lists the polka dot plant as non-toxic, though it notes mild vomiting or diarrhoea can occur if eaten.
| Plant | ASPCA listing for cats | Terrarium notes |
|---|---|---|
| Nerve plant (Fittonia) | Non-toxic | Likes humidity; ideal for closed glass |
| Polka dot plant (Hypoestes) | Non-toxic, mild stomach upset possible | Pinch back to keep compact |
| Boston fern | Non-toxic | Better in large open terrariums |
| Friendship plant (Pilea involucrata) | Non-toxic | Textured leaves, likes humidity |
| Aloe | Toxic | Leave out |
Check each plant you buy against the ASPCA database, using its scientific name, since common names vary. Our cat-safe houseplants list and guide to swapping toxic plants for safe lookalikes give more options.
Lilies Never Belong Nearby
The FDA warns that the entire lily plant is toxic to cats, including pollen and vase water, and that even a small amount can be dangerous. Spring bouquets often contain lilies, so keep them out of a cat home entirely rather than placing them next to the terrarium.
Our guide to holiday plants toxic to cats lists other seasonal flowers to avoid during celebrations.
Building the Pine Plywood Shelf
- Cut a piece of 18 mm pine plywood to fit the terrarium with a few centimetres spare on each side.
- Sand the edges and seal the board with a water-based finish.
- Fix two steel brackets into wall studs, using a stud finder to locate them.
- Screw the board to the brackets from underneath.
- Add a low lip or a non-slip mat so the terrarium cannot slide.
Our stud finder layout guide explains how to locate studs and plan loads. A glass terrarium filled with soil is heavier than it looks, so do not rely on plasterboard plugs alone.
Choosing a Height and Spot in the Dining Nook
Look at the room the way a cat would. Chairs, the table, a sideboard and window sills all act as launch points. The shelf needs to sit well above any of them and away from routes a cat can use to reach it.
- Keep at least a metre of clear wall between the shelf and any furniture top.
- Avoid placing it above a chair back or table edge.
- Do not fix it near a window sill a cat can jump to.
- Leave space beneath so nothing can be stacked under it later.
Our earlier toxic plant swap build for a dining nook uses the same pine plywood approach and works well alongside this shelf.
Before loading the shelf, press down firmly on its front edge with both hands. It should not dip or creak. Check the brackets again a week later, once the terrarium's full weight has settled, and tighten any screws that have moved.
Picking a Closed Container
| Container | Cat-proof rating | Notes |
|---|---|---|
| Glass jar with screw lid | High | Small, light; secure lid |
| Cloche on a base | Medium | Can be knocked off; fix base |
| Hinged glass box | High | Choose a latch, not a magnet |
| Open bowl terrarium | Low | Soil and stones exposed |
A closed container keeps humidity high for plants like Fittonia and keeps cats away from soil and decorative stones.
Multi-Cat Homes and Climbing Routes
Every cat in a household has its own climbing style. One may leap straight up from the floor, while another scales furniture in steps. Watch each cat for a few days and note which surfaces they use as stepping stones in the dining nook. A route that seems impossible for one cat may be easy for a younger or lighter one.
Remove or rearrange the stepping stones near the shelf rather than trying to block every cat with deterrents. Moving a sideboard a short distance or swapping a tall plant stand for a low one often closes the route completely.
| Observed route | Change to make |
|---|---|
| Chair, table, shelf | Move the shelf further from the table edge |
| Sideboard, sill, shelf | Shift the shelf to a wall without a sill nearby |
| Bookcase top, shelf | Lower the bookcase or move the shelf higher |
| Window perch, shelf | Keep perches on another wall |
Re-check routes after any furniture change, including temporary ones like extra chairs for guests. A single misplaced chair can open a path to the shelf in seconds.
Spring Refresh Routine
- Take the terrarium down to a table away from the cats.
- Trim overgrown leaves and remove any dead material.
- Replace a little top soil and refresh moss if needed.
- Wipe the glass inside and out.
- Check the shelf brackets for movement before rehanging.
Do the refresh with the cats in another room. Loose soil, cuttings and tools left on the table are an easy target.
Watering and Humidity Without Mess
Closed terrariums need little watering, which helps in a cat home because there are fewer occasions to take the container down. Mist lightly when the glass shows no condensation for several days, and use a narrow spout so water goes onto the soil rather than the leaves.
Keep the mister and any fertiliser stored in a closed cupboard. Plant feeds and pest sprays can be harmful if a cat licks spills, so check labels and avoid using them near the cats' areas. Where possible, choose plain water and good light over chemical treatments.
Keeping Cats Busy Elsewhere
Cats that have enough to do are less tempted by décor. Offer a scratch outlet, a window perch and short play sessions near the dining nook so they have their own reasons to be there. A pot of catnip or silvervine on a windowsill can give them their own greenery to enjoy.
Cat-Safe Terrarium Questions
What can I plant in a terrarium a cat might reach?
The ASPCA lists nerve plant (Fittonia), polka dot plant, Boston fern and friendship plant (Pilea involucrata) as non-toxic to cats. Polka dot plant may still cause mild stomach upset if eaten. Check every plant by scientific name against the ASPCA database before adding it.
How high should a terrarium shelf be?
High enough that no chair, table, sideboard or sill gives a cat a launch point to reach it. Aim for at least a metre of clear wall between the shelf and any furniture top below. In multi-cat homes, plan for the most agile climber, not the average cat.
Is an open terrarium safe with cats?
Open designs expose soil, moss and small stones that cats may dig in or swallow. A closed glass container with a secure lid is safer and keeps humidity high for tropical plants. If you prefer an open bowl, place it in a room the cats cannot enter.
Can I keep lilies near a terrarium?
No. The FDA warns that every part of a lily is toxic to cats, including pollen and vase water, and that small amounts can be dangerous. Keep lilies out of the home entirely rather than relying on a high shelf, since pollen can drop and stick to fur.
