how to kill the lawn?

Hiyah Melissa,

There are machines that you could rent to de-turf your lawn--cutting it under it's roots and letting you roll-up strips of it, which you could dispose of later (like onto your compost pile or to let a friend use the strips for their lawn.

Anyway. If you are planning on making raised beds where the lawn is I would suggest that it is best to first double dig the lawn before dumping the new dirt/compost mixture for your new beds. Do not rake the double dug ground after turning it, the uneveness will be filled in by the finer dirt that you will be dumping on top--a sort of meshing of the two, you see what I mean?
The reasons for this are that there will then be a more "natural" binding between the present lawn and your newly dumped soil layer...secondly, and perhaps more importantly--you can avoid having what would effectly be a 'pan' under the new earth.
Why is this important? Well because if there is what is known as a "pan" under the new soil it can be so closed and hard that water going onto the beds from a garden hose or from the sky might not drain away properly and remain sitting there like a sort of pool, resulting in water-logging and this would not be good for your flowers or crops. It wouldn't be the first time this has happened.

I know that it is extra work, but I honestly believe that it is best. I would do it this way if I were in your circumstances...without doubt.
Double digging is something that I believe you should do whether you kill or remove the grass or not. It's removal is not the essential thing here.

I am a very strong believer in the proper care and treatment of soil because in my view, soil is the very essential basis for gardening in a convential way and thus proper handling of it and treatment of it is the single most important aspect of successful gardening.

_________________
Sjoerd http://www.volkstuindersvereniginghoornenomstreken.nl/Page11.html

I have to agree with the added work. I have family that have tried to simply fill over the old lawn to start new ones or put in flower beds and every time it became a soppy muddy mess. Of course it doesn't help that we get a lot of rain here but I would error in the safe side anywhere.

Personally, I would dig up the grass and even a little lower into the ground, then I would put in a 2-3 inch layer of small to medium sized gravel for drainage and then fill with planting soil. This could also help with aeration if the plants you are putting in have deep root systems.

I have even seen it done here where the bed was layered. The very bottom had a layer of gravel and the actual bed was 4-5 inches narrower than the layer of gravel. Basically a gravel bed was made and then the flower bed was put on top of it leaving the front 4-5 inches of gravel exposed for aeration and drainage. Looked really good and the plants thrived so is an idea.