Compost or plants (Lazonby CA10)

I work in a local primary school and we are hoping to start a garden and also use plants within our mud kitchen. We have procured lots of planters and have some seeds to sew. Ideally plant wise we would be looking for: woody herbs, fennel, verbena, lavender, dahlias, strawflowers. But really if you can help us out we would accept almost anything!