I have an idea for grapes growing but I don't know how to write a business plan & proposal for it?

I'd start out by reading our standard business plan outline.

http://articles.bplans.com/writing-a-business-plan/a-standard-business-plan-outline

While every business and business plan is unique, the component parts of the plan remain the same.

Thanks for asking, let us know when you have more questions about your plan!