The "ASK" is often the most difficult part when looking for donations I am really uncomfortable with it personally. For me a grant is a little easier since the ice is broken with an outline of the project.
I would suggest some deep research into Community Gardens and Food Forest successes to reference and bolster your "ASK".
The plan should include land acquisition or commitment from a land owner for the projects life. Costs?
Maintenance requirements initially and for the life of the project. Costs?
Interested community members and commitments of labor and material from those community members. If you have a location and can begin initial startup, being able to show the interest and need or desire for your project that would be a plus. Any work or donations should be clearly documented and tracked for use as in kind donations. Since some grants are wanting that equivalent monetary or portion of community commitment.
Who will benefit?
Tracking of success, community involvement. Could this be piggy backed with a youth or troubled youth program? Senior outreach? Being able to assist another organization or do additional good works and tracking that aspect of the project would be separate but maybe an additional selling point.
Is it solely (souly) religious in nature? Is it open to everyone without having ministry involved. It might matter.
How will you maintain and continue to flourish?
Budget throughout initial start up, during and up to harvest.
Those are my suggestions for beginning your request outline. I'm sure that others will have suggestions. Break out that legal pad: people need food...people need affordable food...people need good food...with a food forest.....