A child can use an adult-sized sleeping bag by half turning the bag inside out or by tying off the bag with a belt at the point where the child's feet reach to. As the child grows taller, the belt can be moved down the bag.
SLEEPING BAGS
There are three main types of sleeping bag insulation; natural (down or down and feather) synthetic fibres and fibre-pile.

When not in use, filled sleeping bags should be stored loosely in a large cotton bag (such as a pillow case), hung up in a wardrobe or laid flat under a bed. Do not leave your bag compressed in the supplied stuff sack. Doing so will shorten the bag's useful life. Fibre-pile bags may be stored in their stuff sacks. Note that all down and synthetic bags will eventually lose some thermal efficiency after several washes. Using an internal liner and occasionally wiping the outer with a damp sponge will minimise the number of times a sleeping bag has to be washed.

Cleaning a down bag is a time-consuming business that needs to be done carefully. For this reason many manufacturers and retailers recommend the services of a specialist down cleaning company. If you wish to hand-clean your own bag, contact the manufacturer for detailed advice.

Synthetic bags can be cleaned in a large washing machine or bath using a small amount of mild soap powder or soap flakes (not detergent). Rinse the bag several times and tumble dry on a very low heat. Air and dry thoroughly before storing.

Unlike down or synthetic bags, fibre-pile bags like to be cleaned! You can wash them in the same way as a fleece jacket. After drying, gently comb or brush the fibre-pile so that it fluffs up.

Warning: under no circumstances dry-clean any sleeping bag. The chemicals involved in dry cleaning may damage the bag, and the fumes released are poisonous.