In The Garden
Children enjoy growing plants, from digging plants, weeding and watering. You don't need a garden to encourage children to be gardeners. Most plants will grow in tubs, hanging baskets and pots, and many will grow on window sills and window boxes.
Seeds and pips from fruit cost nothing and garden seeds cost little. Collect safe seeds and other fruits on walks and outings.
Use yoghurt pots for planting, then all you will need is some compost or garden soil and a watering can to make a greener environment for children.