Eggs and the first whorl

A garden snail lays its eggs in damp soil, under a stone, or in a pocket it digs with the front of the foot. The eggs are small, round, and translucent or milky, each with a shell of its own that contains calcium. A clutch from Cornu aspersum is often several dozen and sometimes around a hundred. The number moves with the size and condition of the parent. In warm, moist soil the eggs may hatch in two to four weeks. Cold and drought stretch that interval, and a clutch that dries out simply fails.

The hatchling already has a shell. The first whorl, the protoconch, forms before hatching, and the animal adds to it from the mantle as soon as it feeds. A baby snail is not a soft larva that will acquire a house later. It is a small snail, able to crawl, rasp food, and lose water. The early days are the dangerous ones. Hatchlings dry faster than adults because they have more surface for their volume, and they fit in more mouths: beetles, small mammals, other snails, the gap under a hoe.

Parents of the common garden species do not brood. They cover the nest and leave. A few land snails do guard eggs, and some bear live young. Some aquatic snails carry juveniles on the shell or in a pouch. The garden default is a buried clutch and no further care. Survival is a numbers game played against the weather more than against parental neglect. There was never a plan to return.

If you uncover a clutch while moving a pot, cover it again with the same damp soil. Eggs left on a dry surface collapse within hours. There is no benefit in taking them indoors to save them. The soil, the depth, and the moisture were the whole provision the parent made.