I plan to make a new slightly raised bed in my large area of lawn. I am not exactly sure how deep it will be or how big. I am ordering 7 yards of planting mix from the nursery and I will use rocks to for the border. I may add bags of topsoil and compost if I think the seven yards is not enough. Originally when I had a landscaping company give me a quote to make it they insisted the lawn had to be removed there.
Can anyone tell me why? Wouldn't the dirt on top of it just kill it? Could I at least cut a corner and just use something like Roundup and kill the grass?