This is my basic indoor care system for baby Indotestudo elongata. I should stress that I keep groups of clutch mates together so they have a bit more room than is typical for individual hatchlings. I would use at least a 30 inch long habitat for an individual, though. This primarily would be to allow a good temperature gradient which I think is important to any chelonians indoors.
I maintain mine in a tank which measures 36 inches by 24 inches. Under approximately the front right hand one third of the tank I have an under tank heater and an basking incandescent spotlight of 75 watts placed to shine upon the substrate in that area. This allows for a distinct temperature gradient from the high in the right front corner to the low in the back left corner where the hide box is located. I also have a double fluorescent fixture that runs the length of the habitat. This fixture has a full spectrum fluorescent bulb in it. The lights are on a timer, providing about 14 hours of daylight. Keeping two temperature / humidity gauges, one at each end of the tank, will help you monitor the micro climate.
As a substrate I use a combination of (by volume) 1/3 leaf litter, 1/3 sphagnum moss (The coarse type used by florists, not the type used in gardens) and 1/3 topsoil (potting soil would be ok here as well but it is very important that there be NO perlite in the soil mix as they will eat it). The substrate is about 1 to 2 inches deep throughout the habitat. I mist the substrate daily with a garden sprayer as well as using a humidity engine feeding into their hide box. I spray the rear part of the habitat more heavily than the front to provide a dampness gradient from front to back to contrast with the temperature gradient from right to left. (Trick of the trade: watch where the tortoise hangs out in this type of setup and you will be able to fine tune the habitat to it.)
The humidity engine is simply a gas sparge bottle hooked up to an aquarium pump. The bottle is filled with water and the outlet tube is put through a hole in the roof of the hide box, in effect duplicating a tortoise "pad" or "scrape" micro climate.
As a water dish I use a flowerpot saucer (the shallowest that I could find), about 10 inches across. This is kept filled and cleaned as necessary. I use smaller saucer of the same type as a food dish. If you can find glazed saucers, they work a tad better by virtue of being easier to clean. If you do find some that are glazed, soak them in a vinegar solution, then a water solution for a day to ensure removal of any surface heavy metals in the glaze. I use standard terra cotta saucers.
I soak the babies every morning in very shallow, slightly above room temperature water as part of my daily care. This ensures that they stay hydrated and also seems to get them moving and triggers defecation. (Trick of the trade number 2 here: The fact that they defecate during their bath means less cleanup in the habitat and longer between large scale cleanings). After their soak I put them back into the habitat and feed them. After they are a year or so old I reduce the soaks to once every three or four days, then even further as they age.
I know I get a bit of disagreement with my feeding schedule, but I feed babies once every day. It is my view that they are small and the volume to surface ratio is much lower than adults, hence feeding more often in my mind is a necessity. In fact, for the first two months of life I occasionally feed my babies twice a day. Once they are a few months old an occasional missed day or two every week or so won't hurt them, though. Once over a year old I feed lighter meals while indoors, and when outdoors in the pens they are fed very little supplemental food.
I feed as varied a mixture of foods as possible. Typically during winter I would use a finely chopped mix of (in order of volume) endive, romaine, escarole, kale, ground timothy hay and non citrus fruit. I make a large enough batch of mix to last 4 or 5 days. This eases the work load considerably and the mix keeps well under refrigeration. The reason I finely chop it is because in the wild a tortoise is biting off pieces of plants against the resistance of roots. In captivity they don't have this resistance and tend to get larger pieces. To help duplicate the wild I chop finely. As the weather warms I replace as much store produce as possible with dandelions, clover, plantain, young grape leaves and young mulberry leaves. I no longer feed any supplemental protein though the hatchlings are quite adept at tracking down worms and slugs in their pens.
Cuttlebone is constantly available to the tortoises at all times
Special note: If you can find napolitoes, (cactus pads) they are very good for them and they LOVE them. be certain to remove the glochids (spines) before feeding
To all the above food I add a sprinkling of calcium supplement with D3 (I think all brands of these are pretty much the same as long as you make sure they are not a calcium phosphate base.)
I also offer a small dish of dampened artificial tortoise food every few days and have been experimenting with adding some powdered artificial food to the salad mix. The reason for this is to acclimate them to this food in case fresh greens are not available.