Depending on what stage your school garden project is at, funding a paid staff or support stipend might be a good idea. If you are just starting out looking for ways to fund a garden coordinator keep in mind that many schools are scrambling just to fund current teaching staff, so use good judgment when suggesting funds from your school or district.
There are many models where non-profit organizations partner will schools or districts to provide coordination, resources, maintenance, and instruction for garden programs. Often there are staff that share multiple garden sites.
Try looking outside of the box and think about who else might support garden related work. For example municipal waste reduction offices (composting), county health or health related organizations (nutrition education), after school programs, and watershed education (bay friendly gardens) are all models that we have seen fund or support garden programs. Although not all these models provide staffing they often provide resources to support garden-related learning.
We have seen one model where a supportive principal provides funds for 20 substitute days to allow a fifth grade teacher to run a garden program for all upper elementary students. The teacher coordinates the garden and a small group of parents to run the program. View Judy discussing her program.
In Santa Cruz, garden educators were written into a education parcel tax which funds general city school educational projects, gardens being a small part of it. Pretty cool, but not all cities have the potential to approve an education support tax. Start by connecting with your school board or education foundation to see if you have an existing parcel tax. Think about your community's needs. Your community might be interested in funding a food & nutrition education program, science education, after-school programming, or environmental literacy programs all of which could have a gardening component.
In San Francisco proposition A funded school greening which in many cases includes areas for outdoor learning. This doesn't exactly answer the question of funding support staff but it does demonstrate looking towards policy and thinking outside the box to make great change.
In the District of Columbia the Healthy Schools Act was passed which allocates close to 6 million dollars annualy to support school gardens, improved meals, and nutrition and physical education.
Grants are often thought of as a means to fund staff or support stipends but many of the popular school garden grant programs do not allow funding staff nor do they award enough money to support staff. This does not mean you should disregard grants as a potential funding source but consider grants as one of many options to find funding.
Of course bake sales, plant sales, fundraising, PTA/PTO all can be tapped but it is hard row to hoe to raise enough money for staffing and might be less sustainable than the models listed above.
If there is a will, there is a way. Start small and grow.