is growing asparagus plants a job i can do myself?

You can, but it's a long game. Buy one-year-old crowns rather than seed, plant them in spring in a trench with the roots spread out, and then don't cut any spears the first year. Light picking the second year, properly after that. A bed keeps going for well over a decade, so the spot matters. Which is the catch with your lawn - asparagus wants full sun and good drainage. Half shade will give you thin spears. Keep the bed weeded, it hates competition.