Maybe consider the educational value of letting things get diseases and insect pests? You might even get administrative buy-in to do spray vs no spray controls to highlight the modern agricultural system.
Or N vs no N fertilizer in different boxes and compare phenology and yields etc.
I looked up Castro Valley and saw Bay Area so things like peas might grow well in the spring (?). But no idea… that climate is so totally foreign to me. I just know that SF has always been awesome to visit in March/April or August relative to Iowa (the American Chemical Society meeting rotates through SF often). Much warmer and less dreary in Spring and less than god-awful humid in August. Peas of course bring with them thoughts of Mendel.
Corn (maize) is kind of cool because you can observe genetics in a season as the phenotype of kernels is set by pollination - e.g. you could plant one of the sweet corns that is supposed to be isolated with a dent corn and get a mix of kernels.I think there might even be education kits for corn genetics.