Slowly.
snails grow by eating it is so true if you have a snail that you want it to grow the best food to give is lettuce that's what i give to my snail to make to grow.
I have a large apple snail, about a baseball size. I feed it only with Romain lettuce. It survives well.
leaves!
leaves
For a water snail You will need to do a weekly 20% water change or your snail will die of ammonia poisoning. Occasionally (once every month or so) vacuum the bottom to clean up the waste that the snail produces. Also feed it lettuce or apples or carrots (washed well in warm water) and remove the uneaten food in 24 hours. For a land snail no you will not if you have a dirt bottom. Also feed it the same veggies and remove the uneaten food after 48 hours. Feed both types of snails cuttle bone or eggshells for calcium to develop a healthy shell. Good luck!
Algae, so you don't really need to feed them as they "feed" themselves.
Calcium Carbonate
Calcium carbonate
Grass, leaves, newspaper. Well I feed my garden snail cucumbers, apples, lettuce, bananas, carrots and you should feed it eggshells or something else that gives good calcium. snails like most stuff you would put in a salad they like lots of fruits and veggies. =)
I have discovered snail trails eaten into a degraded concrete pathway around a millimetre or so deep. I can only presume that by doing this, they aquire calcium for their shell.
In the chemical composition of snail shells the major element is calcium carbonate (97.5%); the rest is represented by calcium phosphate and silicate, magnesium carbonate and oxide, iron and manganese oxide and other organic substances.