Well well well

The mock well is going to go in the new patio plan which extends from the new deck. 

It was previously full of soil, compost with a couple of plants, until yesterday when I decided to move the plants further up the garden; a heuchera to the back - you might see the pale yellow/green leaves on the photo, and a lavender which is on the left of the rockery, obscured in this image. 

Once the plants were out I decided to remove all the soil and use it for other areas of the garden. It's pretty good soil!

When I carried on digging down I realised there was a solid bottom, see the second pic. 

Now we have a dilemma; can we use the shape for a fire pit? Or a rain water sitting pool? Can we make use of it? What else could go in it's place?