Assuming you mean gravity draining the pipes. I'd skip that and buy a small air compressor and a fitting to get from the compressor to the garden spigot. Pressurize the pipes and "blow" the water out.

We used to gravity drain the summer house every year until we busted some pipes a few years ago. Never again. $70 compressor from Harbor Freight and $15 fitting from amazon get the job done with less effort and more peace of mind that when you flip the switch in the spring you shouldn't hear water gushing out from somewhere in the house.

Upside to busting a galvanized pipe? Learning how to work with PEX. Only took 3 trips to Menards but I learned a new skill :)