Spread our the tarp on a flat surface outside.
Lift the concrete blocks upright and lay them out on the tarp.
Place a mask on your face.
Shake the spray paint can. Use spray paint made specifically for stone or concrete. In a sweeping motion moving from the bottom of the block to the top of the block, cover the block in paint. Try several different colors to create a bright, bold, urban feel to your garden. Allow the paint to dry.
Arrange the blocks around the perimeter of your garden or in random places in the garden bed. Place some on the ground cover; bury others halfway in the ground. Be creative.
Fill the blocks with soil and seeds or young plants, using the hand trowel. Water regularly.