Hi -- This spring I created a large perinneal garden using lasagne method and also converted and enlarged two other established beds to this method. They are all thriving.
What I did on the established beds was put down strips of cardboard on the edges to help with trimming and grass incursion and then put down castle stones for edging. So I knew where the top of my garden should be. For an existing large plant (such as a fern) I lifted it out and planted it shallower. You have to sort of go by your intuition how deep to put them back in, not covering the crown. Yes, I did put wet newspapers down all over, and carefully around plants I didn't move. I layered with chopped leaves, peat, compost, bagged garden soil, etc. I would chop or shred your leaves.
I'm really happy with all the beds. The ones existing don't look any different from the new bed. Maybe because they are raised a bit, but I find I don't need to water nearly as much. The good stuff in the layers holds the moisture and there's always a layer of shredded leaves on top. The only grass that shows up is really easy to pull out, but it's minimal.
To me lasagne method is the greatest because I'm just tired of digging gardens. They say the second year is even better, and I'm looking forward to that.
Just have fun and don't worry.
Best to you -
Sunny

You can kind of more or less create a Lasagna Bed on an existing bed, but mostly that is simply good, organic gardening practice rather then a real Lasagna Bed.
Newspaper is used to suppress any plant growth, not just grass and the newspaper will not suppress the invasive grass. I often put newspaper down on already planted beds to aid in making the mulches go further when I might not have enough.
You can work around the existing plants or cover them up, depending on whether you want to keep those plants.
Put the compost, about 1/2 inch layer, on the newspaper, cover that with the coffee grounds and shredded leaves.

I'm a totally new gardener, so please excuse the questions. What's planted now is lilies (well, lily stems, after the rabbits were through with them), black eyed susans, echinacea, salvia and the like. The're perennials but not all-season. So would you work AROUND those, or cover them up? If I newspaper over them they wouldn't come up, right? But don't they die to the ground come winter? If I just did regular organic practice would I just mulch around them in layers of UCG and shredded leaves? Thanks!

Really all you are proposing to do is mulching, (or sheet composting to some,) the age old method of putting organic matter around your plants to keep weeds down, conserve moisture and feed the soil. It's a technique that has been around for countless years before the Lasagna Lady wrote her book and tried to give it a new name.

Use the newspaper if you don't have a lot of other organic matter. It won't hurt, but I don't use it if there is enough other stuff, like grass clippings, chopped leaves or wood chips to do the trick. (I hate newspaper in the garden, primarily because of the unsightly mess it makes when the chickens discover it and scratch it to ribbons.)

Your plants are firmly established in your soil where, in my opinion, they belong. I'd recommend against ever planting perennials using the so-called "Lasagna" scheme. Your plant's crown belongs only at the level of your soil, never at the level of the mulch or compost which will rot away and disappear in a relative heartbeat, leaving your plant's roots dangerously exposed to the elements.

Wayne

Okay, I think I'll skip the newspaper then. So when would I do the sheet composting? Now, continuously, or in the fall? IF now how do I treat the bed differently in the fall? Do I cut down the dead growth after frost or leave it alone and mulch with composting? I'm sure these are silly questions but like I said, I'm completely new to gardening. Thanks!

There are no "dumb" or "silly" questions. We all learn by asking them. When you were 3 you asked tons of them, but probably like most of us were told at some time to "don't ask so many questions" most likely by someone that had no answers, and that is why many people think they should not ask questions. The only "dumb" question is the one not asked.
Many of us have continuous mulches, the mulch material is there all the time and is renewed as needed. Soil should never be left bare, exposed to the ravages of the sun, wind, and rain, but should be covered with something all the time. If you do not have enough material to cover your soil that needs to be covered then the newspaper will help extend that material, so instead of say 5 inches of shredded leaves on your soil you could plunk down 4 or 5 sheets of newspaper (around the existing plants) and cover that with a couple of inches of the shredded leaves and get the same affect.
When frost kills offf the top growth of most all of my planting beds that top growth stays where it grew so it will replenish the soil with the nutrients that plant removed during the growing season. I could cut them down, haul them to the compost pile, and then when the compost is finished haul that back, but it is much less work to just leave them.