Allow teachers to use the garden in their lesson plans, getting kids involved in the prep work, planting, maintenance, and harvest of the produce. This provides great curriculum for a summer school session.
Sell the produce each week to parents and community members. Consider selling shares of the garden produce on a prepaid basis. This will provide the funds upfront needed to start the garden. Then each week divide your produce among the number of shares.
If you have enough space, plant some pumpkin seeds in the spring and harvest the pumpkins in the fall. Allow kids to pick their own pumpkin for a donation to the school.