Turning my existing lawn into something more presentable. Will tilling kill everything so I can start from scratch or do I need herbicide?

Question

I'm in Eastern PA and as it's just the start of April - I would like to turn my poor excuse for a lawn into a nice, level, uniform grassy green lawn. It's currently very uneven with high spots, low spots and rocks - I'm working on leveling everything by getting rid of the rocks, eliminating high spots and adding new top soil in low spots. This part seems pretty straightforward. I'm not sure how much of the lawn is actual grass and how much is unwanted stuff like moss and weeds. Considering I'm going to be doing this now (first week of April) - will tilling the whole lawn kill everything that's there now? Or would I need to treat it all with herbicide first? Here's the process I had in mind - I'm looking for some critique if I'm doing anything wrong:

1. Remove excess rocks & high spots

2. Fill in low spots with fill / top soil

3. Till everything, mixing in some new top soil to get a consistent soil

4. Level everything with a homemade drag level

5. Spread grass seed

6. Add an additional thin layer of top soil

7. Use a lawn roller to compact everything

8. Water & wait

This is what it looks like today (April 2019):

This is what the yard looked like last summer (July 2018):

Answer 1

Tilling on its own will just unearth more weed seeds, break up any moss and spread it everywhere, and most likely fail to kill the old grass as well.

One "organic" way to kill the grass is to skim off the "turf", dig the ground with a spade, and bury the turf upside down in the bottom of each trench as you dig. This is more or less impossible to do with machinery, unless the area is big enough to get a local farmer to plough it - preferably just before winter, so the winter weather can break down the soil and help to level the surface.

A systemic herbicide plus moss killer is a lot less work and just as effective, unless you have personal objections to "using chemicals".

For the rest, steps 5 and 6 and 7 are in the wrong order. First get the ground level and (lightly) compacted, then add a layer of topsoil if you like, and finally sow the grass seed. If you think about how grass grows in the wild, the seeds don't get buried by anything, and it germinates just fine on the surface. Just rake the lawn very lightly after you spread the seed.

Answer 2

The traditional way is "rake, seed, and roll."

In your case, you want to level it. Since you already have some working grass, use it.

Mow the lawn as short as you can. If you scalp some lumps, that's ok.

Spread an inch of new top soil. and take your time to get it level. Water lightly. Roll it. If your roller leaves tracks where the edges are, you are too wet. Let dry.

Spread the grass seed of your choice. Roll again to press grass into soil.

This won't give you a perfect lawn. Your pix look like you have areas of coarse grass and areas of find grass.

The way to get rid of the coarse grass:

Mow. Wait 3-4 days until the coarse grass is taller than the fine grass. Using a weed wick applicator set it to be about half the difference between the height of the course and fine grass. Go over the lawn. Only the coarse grass is tall enough to touch the wick.

You may have to repeat the seed and roll in the fall or spring for several years. (Best time of year is climate and grass species dependent.)

Answer 3

You could can cover the lawn with cardboard, put some couple of inches of soil or mulch on it. This will kill the grass/weeds and also you can flatten and level the lawn. Then you can sow new lawn over it. This technique is called sheet mulching. There are many videos and other info on the interwebs.