Removing Grass
I've done 2 things.
- Rented a rototiller (with rear tine preferred). They're heavy and hard to use IMHO but it definitely gets the job done with several passes. You can also rent sod a cutter.
- Lay down cardboard and cover with several inches of compost/garden soil. I ordered a 250' roll of 2' wide cardboard off Amazon and used that to create the new bed along our retaining wall. It was fabulous because I didn't have to peel off shipping labels or packing tape. In order to plant right away, you'll need 5-6" or deeper soil on top for planting tubers. The glue used in the cardboard creating process attracts earthworms, which is great.
When I was in my twenties, I used a flat bladed shovel(spade?) and removed the sod from my 20 x 20 vegetable garden . Now that I am in my late 70s, I would spray the grass with round up and then use my 48 year old Kubota tractor to till the soil. Or, I would leave the grass and not do another garden space!
Krista I’m hoping for recommendations for removing lawn by hand
It depends on the variety of grass. If it has rhizomes (e.g. bermuda grass) I would use the nuclear option (roundup) and definitely do not rototill. Alternatively, if you feel young and frisky you can spend hours picking out the rhizomes.
If it is an annual grass I would just turn it over and plant, no need to remove it. That is what I do.
MissyWeitzel Thank you, hearing that rear-times is preferred with rototillers is great advice! And for some reason I’d assumed the cardboard method would be a longer-term, fall-prepped plan. It’s cool to hear I can be successful with this using 6” of soil on top actually. Thanks!
SteveM Do you know if general lawn seed that most folks would use for their yards will spread via rhizome? I’m so unfamiliar with “lawn” and ornamental grasses. This lawn came back from last year, no problem, so I imagine it isn’t an annual. I may have to take the “young and frisky” route even if that’s not how I’m feeling. 
Bermuda grass does not grow in Seattle.
Krista Yes, with soil/compost on top and watered regularly, the cardboard is quickly going to be penetrable for roots. For large areas of grass I have also applied "round up" with a paint roller which could be combined with a long pole so you are not bending over. I never spray it for a variety of reasons. Then you could then top it with cardboard and soil. The grass and turf is going to be breaking down, so maybe a bit of extra nitrogen?
Krista I don't about Bermuda grass in the PNW but I do remember my father paying me 5¢ an hour to dig and remove the rhizomes of what we called "quack grass' in Montana. 
If you dig up one plant you will know if it is spread by a rhizome. If so, they will need to be pulled by hand (or nuked)) and do not multiply them by rototilling.
Bermuda is the worst. I think of it as a warm climate grass though. We had it in Houston. Nothing could kill it.
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For those not familiar with Yakima....It is as different from Seattle as two cities can be! They are on two different sides of the Cascade Mountains. Yakima is famous for growing cherries and peaches, plums, apples pears...watermelons. Seattle is famous for fog, rain, sea food, slugs and lovely summers (Once the sun comes out and warms things up after the 4th of July). Winters in Yakima will be much colder then Seattle. And there will be Snow. And frosts. The last time I was in Yakima it was August and about 112 degrees. Or more. And we had hit a deer on the freeway going over the pass from Seatte and ended up marooned for hours in the heat just trying to GET to Yakima for a family reunion...You know, have the car towed (eventually back to Seattle) where it was repaired...find a rental, process all the paper work...I think that was all in Ellensburg then we still had to get to Yakima! So watch those deer on the passes while you are moving, Krista! We were in the 3rd lane of the freeway and it jumped between a big truck and a car right onto our windshield.
SteveM, I am so glad you're able to advise not to root till this type of grass. Thank You! I certainly wouldn’t have known better. And I’d take any payment for time spent on this today, to be honest 
I guess I’m actually paying to do this.
calico20hill What an adventure, Noni, I will be careful of deer as best I can on the drive; I’m glad you were all safe! And thank you for explaining the difference for clarity that being on the other side of the Cascades poses. It is absolutely a whole different climate, and I imagine I’ll once again have to experiment new methods for tuber storage as the air is world’s dryer than the PNW.
blown_dry I had not heard of using roundup safely just by not spraying. I’ll do some more research about this, thank you! Using a paint roller with a long handle is genius.
Round up is a useful chemical in moderation and with lots of precautions. I spray it no more than once per year and may not this year.
Krista I also wear waterproof disposable gloves. I don't want to say this makes it safe, but it must make it safer and makes it much more controllable. I usually apply with a paintbrush instead of a roller, because my usual application for it is bindweed. I also have "tree bindweed" aka mayten tree. It sprouts from roots and it crops up, sometimes 30 feet from the original trunk (long gone now) and very quickly grows tall. Presumably the "instant tree" aspect made it attractive in landscaping, but it is a menace.
blown_dry This is very helpful. I’m sorry to hear about the tree bindweed. I will soon be trying to figure out how to remove an age-old wisteria growing over the trellis outside the sunroom. Runners are exploding all over the lawn and around the foundation of the house which doesn’t bode well. Not sure I’ll win the fight on this one without a nuclear option so finding out how you manage it is very very encouraging.
Krista I actually have pretty successfully removed a very well established wisteria from our property. It took several years of pulling up runners whenever I found them, but it was doable. Use stump killer on the main “trunk” if you can - it helps.
I keep roundup on hand for 1) Poison Ivy (but I don’t find much of it) and B)Canada thistle, which seems to be slowly taking over the world in these parts…. So hard to get rid of that stuff, even with round up.