Considerations:
Before you put anything in your snails habitat you need to clean it thoroughly to make sure their in nothing on it that may harm them. This also gives you a chance to check for any sharp edges which may cut your snails foot. Every few months you will want to replace their furniture so they stay clean.
All furniture should:
~!~ Be free of sharp edges which could cut their foot.
~!~ Have no holes which any size snail, large or small, could try to crawl through or into and get stuck.
~!~ Usually be made of a non-porous, easily cleanable material like resin or plastic.
~!~ Woods should be thoroughly cleaned every few days. You can soak it for an hour and then bake it in the oven for a few minutes or run boiling water over it and allow it to completely dry. Replace about every month.
~!~ Be securely positioned so it cannot tip over.
~!~ Branches and woods should be free of any pesticides or chemicals.
~!~ Never use rocks of any kind because they can fall on them braking their shell.
~!~ Never use anything but hot water, a new clean tooth brush and your hands to clean their furniture especially their dishes. Hot water, letting it dry completely and replacing old furniture is the best way to keep it clean.
Snails must have a shallow water dish that's easy to get in and out of.
A plastic reptile dish with built in 'stairs' is the best thing to use as a water dish. Keep in mind it needs to have almost no water in it to prevent one fromaccidentally drowning. An extra small repti rock water dish by Zoo Med works the best. It's a good idea to buy two dishes so you can switch which dish is in their house every day giving them a chance to dry for a few hours. Never use anything but warm water to clean their dishes. Also a terra cotta plant pot saucer is unsuitable because it's porous making a breeding ground for bacteria and they are hard for snails to get in and out of easily making it even more likely for a young snail to accidentally drown.
A medium sized food dish can be used to keep things like powdered cuttlebone, ground oyster shells, cantaloupe, or cucumber out of the substrate but it's better to instead use a leaf of something and use that as a sort of dish instead because then you don't have to worry about cleaning it or replacing it.
Some snails love to crawl on tree branches so long as their thick enough. This actually lets them use some of the vertical space in their house. Try to use untreated(pesticide-free) apple tree branches and they can be fresh or aged. You could also try sand blasted grape vines. Just make sure to replace and clean them often. You could also try oak tree branches. Never place driftwood in their house.
Plastic pots make great snail hiding spots! They need to be new and plain plastic though. A used pot will likely have chemical fertilizer residue on it which would be harmful to them. Terra cotta pots should not be used because they are porous which makes them hard to clean and a breeding ground for bacteria. Also they are hard and if a snail was to accidentally fall onto it they would likely brake their shell. To make the pot into a hiddy hut you simply cut off a side so it lays flat in the dirt with the top rim as the door. That way the edges where you cut are in the dirt and the doors edge is the lip of the pot so you know it doesn't have any sharp spots.
A plastic log hiddy hut like for a fish or reptile makes a great decoration for your snails home, sort of like a couch. Just be sure to check for sharp edges that may cut their foot.
These can be used instead of branches. Simply press into their substrate and instantly an artificial branch appears!
If you would like to give them a fresh veggie or herb treat evey once in a while you can grow some of their favorite vegetable or herb seeds in a tiny pot filled with their substrate! Either the tiny terra cotta pots or mini peat pots work great. Make sure not to use regular potting soil or garden soil which has pesticides and fertilizers. To give the fresh plants to your snails just plant it pot and all in their house! Make sure to take out the pot out after they have eaten the plants or after about a week. A few kinds to try are: broccoli, swiss chard, brussel sprouts, lettuce, alfalfa, turnip, beets or basil.
Not really needed but if you would like to you can use these for fun to tell what humidity/temperature they like best.
The small to medium plastic igloos they sell at pet shops for hamsters/gerbils work well as a hiddy hut.
The backgrounds that you put on the back of an aquarium are a great addition to any snail tank. Especially if you can find one that is more for reptiles and has a terrestrial theme.
First off, using a terra cotta dish or saucer is a terrible choice because they are hard for the snails to get in and out of making it highly likely they may accidentally drown. Secondly, they are hard so if one of your snails accidentally fall on them it will most likely brake their shell. And lastly, their porous and hard to clean making a breeding ground for bacteria!
Rocks are just to hard to be used at all. A falling snail may hit it shattering their shell.
Should never be used in your snails house because they have several deep(for a snail!) puddles of water with they can very easily drown in. Also they are hard to clean making the perfect environment for bacteria to grow. Yes, they would supply needed humidity and running water but it's not worth the risk of accedentally drowning a snail.
Any kind of vine should be avoided because they are not sturdy enough for a snail to crawl on. If they are the "bendable" kind they usually have metal in which can be toxic.
A few bushes of plastic plants may look nice but a snail may fall off it while trying to climb on it.