J.S.
You know he really did not mean to ruin your spinich. I would not be too harsh. First, you let him help you in the garden so he did not think it was off limits to him. Second, he was just trying to help. He said he will not do it again. Do not hold this against your little one. You let him know you were not happy with what he did, he said sorry and promised he would not do it again. Leave it at that and show him some love. I would still let him help you with some things in the garden, just let him know you do not want toys in the garden and maybe only let him in there when you are around! Show hims some love and drop the issue.
J.