When you are ready to make a vegetable garden you simply use a sod cutter to make the rows; 3' wide. Double dig the soil, use a tarp for the first dig of soil, the soil will be up as high as 3' all fluffed up. Dig down at least a foot. Turn the soil over as you go. Then rake flat. I would use the sod cutter to cut out 4' wide rows. That allows a 6"X6" trench at the bottom of your fluffed up beds to collect water. To not allow the water to wash the soil onto the grass paths (minimum should be the width of your lawn mower). Luxurious vegetable garden. Forget about 'competition' with the grass. You will be applying fertilizer appropriate for vegetables. When fertilizing the grass paths use a drop spreader, not a rotary spreader. You do not want high nitrogen in your vegetable beds. Get soil tests. Concentrate on making some beds more acidic 5.5 to 6.0; potatoes, blueberries, acid loving plants. Most of the beds should be 6.5 to 7.0. Make enough to be able to rotate your crops; no tomatoes in the same bed for at least two years...oh to include all of the vegetables in the tomato/nightshade family...eggplant, potatoes, peppers...
For winter make sure you've got seed for covercrops. Annual rye, red clover, buckwheat...there are a bunch of choices. This prevents weed seeds from germinating and taking hold during the fallow period of your garden. Spring you simply turn them over with a shovel. If you don't have clay you can use a rototiller. Add nitrogen and allow to decompose for a month before planting. Super way to build up soil, enhance your soil life, boost the tilth, forget about weed problems.
Some of the most famous gardens are done this way. Go ahead and prepare a great bed for your lawn. Do not forget to compact with a roller at least 3 or 4 times. A sod cutter works so well, sharp edges. Double dig the bed then form with a rake, a sheet of plywood to jump up and down on to compact the soil to get rid of large air pockets and permit great soil/seed contact. Dig the trenches all around your bed throwing the soil up on the bed. You'll have to clean out the trenches once or twice a year in the same way. Do not use any plastic, any non decomposed bark. Do not line with rock. Compost can also be added to the top after plants are up you do not want to plant directly into compost. And compost is not to be used as fertilizer. Add the amounts of chemicals compost provides into the entire formulation you are in charge of adding. Dark, yummy soil doesn't mean it has the necessary chemicals plants have to have to do photosynthesis to make the food they need. Too much fertilizer means death.
Gorgeous gorgeous vegetable garden. Possibly a fence made with welded wire and dimensional lumber to keep out rabbits, dogs, cats, raccoons...glad you asked!
raised beds without lumber and lawn walkways