Sandbox alternative
This was the tricky part. I leveled the sides all round using cornerstones (stepping stones actually) and now I needed to build up the foundation by hand, using stones and dirt.
You can see the hand cultivator which was used to loosen up dirt nearby and then I shoved the dirt under other stepping stones - keeping the stepping stones level as well.
Technically I didn't have to level the stepping stones since they would be covered with mulch but it's good practice and keeps sharp corners from poking up if the kids every dig down far enough.
Sandbox alternative
This was the tricky part. I leveled the sides all round using cornerstones (stepping stones actually) and now I needed to build up the foundation by hand, using stones and dirt.
You can see the hand cultivator which was used to loosen up dirt nearby and then I shoved the dirt under other stepping stones - keeping the stepping stones level as well.
Technically I didn't have to level the stepping stones since they would be covered with mulch but it's good practice and keeps sharp corners from poking up if the kids every dig down far enough.