How to stabilise a star picket with concrete?

[ennoh]

I want to cover a couple of raised garden beds with green shade cloth.    What will work for me is to stabilise star pickets in a concrete cube to be embedded in the ground so the star picket wont move.  I need to pour concrete into a frame of some sort with an empty core in the middle which will hold the star picket.    I will be able keep the concrete blocks above ground.    How can I achieve this?

[ennoh]

genius!    maybe get a small plastic container and oil it up as suggested.  Hopefully that will work as long as the cement doesnt bulge out