Cleaning Ring Culture Beds
 

Hi everybody, another new poster. Last year I built in my greenhouse two ring culture beds 8ft by 16 inches, lined them with plastic and filled them with about 6inches of builders ballast. I then grew tomatoes on them in bottomless pots.
It was very successful.

I am getting ready for this year now and wonder how I am going to clean them.
Removing the stones would be difficult so I was wondering if there was anything I could use to swamp the beds with that would do the job. I was thinking of Jeyes fluid but would it be safe for tomatoes.

Any Ideas ? Many thanks folks.