I use an edger tool that comes with the weedeater. You have to use it, otherwise, the grass spread will be worse. Some mulch will get thrown into the grass, but eventually, a line will form. I bag the grass which helps with sucking up some mulch that gets thrown.

 

I use the Stihl Kombi system with the bed redefiner. It works great and makes quick work of bed edges. There are a number of videos on YouTube that shows how it works.

 

All my beds are natural edge. First, the bed will need to be defined like this. This can be done with a flat shovel manually or with a machine as pictured.


Then spread and lock the mulch in like this;


Using a trimmer held sideways or running an edger along the grass/mulch line every time you mow will prevent the turf from grow into the beds and keep the edge sharp.


Redefining the bed edge once or twice a season, typically done when new mulch is added to refresh the beds. Either manually or with one of these.


It seems difficult, but it only takes a few minutes each mow to keep it tidy and neat once the bed is defined.

 

What a coincidence....I was thinking of posting the exact same question.

I haven't tried it yet, but I may give it a go with my Ego edger. Can't see why it would NOt work, but I guess I'll find out soon enough.
But that Stihl redefiner looks awesome.

 

I have just started on this. I bought the Stihl bed redefiner and it is an awesome tool.

I have a couple hundred feet of beds. I did not like the metal edges that you find at the big box stores, Site One or Ewing. Brick or any other stone is too expensive. My thought now is to use luan or thin formica cut to 6"-8" and hammer it into the soil then mulch up against it.

 

I have just started on this. I bought the Stihl bed redefiner and it is an awesome tool.

I have a couple hundred feet of beds. I did not like the metal edges that you find at the big box stores, Site One or Ewing. Brick or any other stone is too expensive. My thought now is to use luan or thin formica cut to 6"-8" and hammer it into the soil then mulch up against it.

My problem is that the beds do not exist yet, so we don't have anything to redefine. That tool looks useful down the line, but I'm trying to determine the best course of action from bed inception. After researching (including analyzing prices and also determining that bricks/pavers are too expensive for almost 400 feet of beds), I think we're going to go with the "elevated edge" concept. We're going to sod cut a 2.5" trench, and slope the mulch down from back to front, so that by the time the mulch gets to the grass edge, it's below the edge. This will allow me to go in with my Ryobi edger (probably not the most appropriate use for the tool, but it's what I got and I can't see why it wouldn't work) and clean up the edge after each mow. Down the line, I'll look into the Stihl redefiner when the bed has had a couple seasons to become unruly.

EDIT: I missed @Mister Bill's comment above. Basically, what he said.

 

Try the garden weasel edger tool, it's very good for creating the edges. The advantage of this over a shovel or other similar tools is that you place your foot in the center which is more comfortable when you have a lot to edge. When you get used to it you can keep your foot in there and move sideways to edge a few feet at a time.