The French word 'petit' means 'little' in the sense of 'small' i.e, not big.
The English use of 'little', in the sense of 'not much' cannot be translated as 'petit'. The word 'petit' refers to size, not quantity.
Small = petit
Little/ a little ( ie 'not much') = peu/un peu
So
A little garden = un petit jardin ( not big)
A little money = un peu d'argent ( not a lot)