Question
richard,
i have read multiple landscape books and have decided the best way (easiest for mowing) to edge my lawn from my adjacent garden is to dig out an edge aprox. six inches deep and four inches wide. do i fill it? or put down a border of rock (on the inside) it seems like this should be so simple-but...i am struggling here-do you have a suggestion too?  the lawn is bermuda  
thanks-
jayme

Answer
the purpose of lawn edging is to prevent the lawn from entering the flowerbed area.  this happens when roots spread either below or slightly above ground level.  edging prevents the lateral movement of the roots.  it also can really dressup the edged area.  
what you use depends on your personal taste. dig out an area 4-6" deep and 8-12" wide (curve it, make it straight-whatever you like).  you could lay natural stack stone, manmade edging pavers, wooden pressure treated 6"X6" ties, polypropylene(plastic), aluminum, or steel edging.  you could also just mulch up to the area and keep a line sprayed w/roundup to keep a clean edge.
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