In case you just want to move these blocks in a grid and the blocks are the same size as each individual grid, personally what I would do, instead of moving, creating, deleting objects I would simply change the animation of the grid. If you place a dirt somewhere it display dirt animation, if you place grass somewhere it display grass animation…etc
It would be pretty complicated and long to explain how to do it but fortunately I was doing something similar in my inventory example, I hope it helps: