Do I really need a raised bed?

I'm converting two 1500sqft quadrants of our yard into a garden.  On one quadrant I've put several keyhole gardens using sheet mulch of newspaper/cardboard, hay, compost, and leaves.  On the other side I wanted to try something different to see what works best.  We tore down an old barn so we have lots of extra wood, so I figured I'd fill it with raised beds and fill them with purchased soil+compost.

Then I was watching Lawton's permaculture video on Food Forests.  At one point he shows the kitchen garden.  It's simply long rows of piled organic matter or maybe sheet mulch 4 feet wide.  It looks so much more natural than raised beds in a frame, but then it still has the same function of one--doesn't it?  It would be much cheaper and much less work but I'd still have good soil and good drainage.

Am I missing something that makes a framed raised bed a better idea?

hozomeen wrote:
Am I missing something that makes a framed raised bed a better idea?

Not having to bend over so far?

it is all a matter of choice..generally people that used raised beds do so to improve drainage or so thing heat up earlier in the spring, also to get their beds up out of the mud in a wet climate.

however..it isn't necessary to even have raised beds if that isn't what you want..i have both at my property.

the raised beds are nice for easier reaching when you get old..but they also require a LOT more irrigation if you are in a less rain climate

i have a  soaker hose that i can water mine with..but they do still dry out faster.

some of mine are enclosed with wooden boards and some are not..if you slope the sides rather than enclose with wood, you have a larger planting area

I have not had good success with raised beds because I'm in a droughty climate with well-draining soil.  My beds are slightly sunken.

I have had a flat garden, raised mounds and wood framed raised beds all in the same location - the type you have needs to serve your situation.

Regarding the differences between raised mounds and wood framed beds:
I have a wet climate and when my beds were raised mounds I had hay for the paths so I had no mud problems at all, and since they were raised I had no more bending over than what I do now for my wood framed raised beds. 

The devil is in the details:
I started with flat beds, but the roots from my neighbors hedge took over my beds in a couple of seasons (took 'em time to find the good stuff).  I didn't notice the roots when I first prepared the beds because the area was never watered or fertilized so the roots were not there (yet).  After I amended the soil and put in my nice garden, poof  - roots so thick a shovel wouldn't go in without a lot of force.  Thick as spaghetti.

So next I tried mounds (think 3 little pigs story - stick house phase) - they worked great, in every way, except those darn roots now grew up, into the mounds, and in one season would fill them - Arrg!  Shorter leaning curve, the roots were getting smarter.

Now we are to the 'brick house' part of the story - So I built wood framed raised beds and lined my boxes with thick root blocking material - ha ha take that you roots!  But they are still huffing and puffing down there I'm sure, and I don't know how long until a breach in my defenses makes my beds open to invasion again.  I do not like how my garden performs with lined beds as well as I did with the natural mounds, but it's the best I can do while I live here - in the city.

So the lesson of this story is - you do what you have to do to work best in the situation you have.  I'm sure if I were in a wheelchair rolling along side a boxed in raised bed would be the best way to go, but when you are standing reaching the soil in a raised mound or raised box is much the same.  In a wet climate raising your beds does offer a drainage advantage, as in a dry climate planting in ditches does.  But the box is optional in my opinion, unless your fighting invading roots

I have raised beds and really like them. The main reason for me is that I have really crappy clay soil that is alkaline. I live in a very dry (7-9 inches a year) climate. The raised beds helped me have pretty good soil immediately. I did have to do some digging before I put them in to improve drainage. If I had started with reasonably good soil I probably wouldn't have gone with raised beds but would still use the same layout so that I am not walking on and compacting the soil where I am planting my garden.

i find the beds you are talking about work much better on sloped ground than boxed beds. and you get more surface are to plant too so that is nice.

I believe that raised beds can be useful for some applications but they are not the end all be all.

Raised garden beds provide a hard delineation between pathways and growing spaces. The soil you are growing in is less likely to wash away at the sides and ends compared to not having walls encompassing your growing space. These walls also allow your growing space to be higher leading to a more ergonomically friendly position for gardeners. If done right, this can reduce stooping or the need for long handled gardening tools. If you live somewhere with a cold non-growing season, raised beds can warm up quicker than in-the-ground beds. Raised beds can also help improve drainage in some situations.

alternatively, if you have snail/slug problems the raised beds (or bed edging) provide infinite hiding spaces for pests. I edged my gardens with old roofing tiles and as a result I need to wage full-out war on snails several times a year when it's rainy.

Another reason for raised/contained beds (my case, in fact) is if you're on a slope and your nice dirt might wash out, or if you have invasive weeds that will just spread and take over. i have lots of "running" weeds (grasses, wild strawberries) that I have pretty much zero chance against!

If it were me, I'd just do hugelkultur berms, which is somewhat similar to what you were talking about.