Well maybe it can be like this.
Although, organic food is healthy it can be bad economically so a more economical way is to grow your own garden and make organic food that way.
A thesis statement is a non-focused section of text that clearly delineates the argument that will be presented in a proposed paper.
You have all of the makings of your thesis statement in your question above.
It is your argument that organic food is more healthy than non organic and the way to overcome the higher cost of organic can be managed by growing your own garden.