I don't have kids but my parents always made me my own flower bed to play with as a child. My mom had nice orderly beds that she worked on. I was given seeds or seedlings, depending on the supplies we had at the time. My dad would break up the earth for me and remove any major obstacles, but leave some for me work on. He would put a border around it, usually bricks or natural rocks to hold the dirt in place. This was in the Carolinas and there were always rocks around! I remember cleaning out chopped up grass roots and sticks and other stuff.
Then Mom would show me how to enrich the dirt by adding soil and fertilizers, I guess that's what it was, I was just playing and didn't read the bags, lol! Anyway, Mom showed me how to plant the flower seeds or seedlings but then left me alone to do it. Then we would go out once or twice week and pull weeds and make sure things were growing well. If there were pests my parent would handle the pesticides, as I recall. The flowers (zinnias, marigolds, sunflowers) usually bloomed pretty well and it was great fun.
I forgot that I also had my own "row" in the family vegetable garden and I would plant tomatoes, onions and potatoes, I recall. Again, we went out together to tend it a couple of times per week, after school.
I think my mom cheated and would work on my areas when I wasn't around, but, hey, she taught me how to dig in the dirt and grow a few things, so I am thankful!