Hi
On mine I just add clippings throughout the year using a hoe to turn it under. i grow dormant gingers so allow them to idle during winter. When spring comes I throw in a bag or two of top soil or black cow For my summer dormant bed (winter vegetables ) i layer in all the clippings I can find . Top dress with whatever is appropriate for what I'm growing planting in late Oct . This one really gets turned with a hoe as it's empty during summer gary

A Mantis or Honda mini tiller works fine to incorporate finished compost into your beds. It is the vegetative matter in the soil that needs replacing between plantings to maintain the structure and nutrient value of the soil. The compost feeds the soil microbes and buffers the soil PH. Al

As Al implies, the soil itself doesn't need replacing. I also grow in raised beds and, prior to each crop, I aerate them with a digging fork (loosening and lifting the soil but not turning the soil over). I then add a 1/2" layer of homemade compost (when available) and any fertilizers that the new crop might need, and then I work them into the top two inches or so with a bow rake. That's it. If you want to take it a step further, you could do something like John Jeavons recommends in his book How to Grow More Vegetables. I've linked to a freely available pdf copy below.

Here is a link that might be useful: How to Grow More Vegetables...

This post was edited by shazaam on Sun, Sep 8, 13 at 12:26

As Al says, the mini tillers do a good job. Mine is probably from the 50/60s and tills down about 4". This is fine for my raised beds cause I have hardware cloth underneath for gophers and don't want to go any deeper. I also use my mini tiller for my raised up containers that are about 1' deep, perfect for fluffing the soil!
There are also auger type things that attach to a hand held drill that actually pull the soil from the bottom and truly mix it.These work well, but can be hard on the back, due to kicking up if you aren't situated right! Nancy

Never need to replace a garden soil, be it raised bed or flat bed.
All yo have to do is add some compost, composted manure to it. Just in case it overflows, take some of it out and use somewhere else.

I don,t think getting a tiller to a 3ft high , 30 sqr-ft area is a good idea. I would just get up there and turn it the old fashioned way. Then add the new amendments and work it in. .

OK, even though I responded to this about using my small tiller, in another post (thinking about buying some raised raised beds), I was told not to use compost etc, but to use fertilizer for my raised containers
I'm still going to replace most of my soil, cause my sister used some of the same stuff in her in-ground beds and her plants didn't do well in that area.
I have several compost bins and can till it in a couple time a year. Compost or fertilizer?
Jennie, I don't want to take over your thread, just want some clarification. Nancy

I use my raised beds for strawberries, blueberries and raspberries. So something is always in them. More and more experts say tilling is not a good idea, I hear it all over the country on garden shows. I like to listen to pod-casts.
Anyway I can't since my beds are always occupied.
You want to always use compost and fertilizer. At least I want to. Keep the soil nice and rich. I just work it in the top, or just mulch with it. I do add mulch also. I use pine needles. I have an unlimited supply.
The corn pictured was harvested, over 60 ears! The stalks are now buried in the bed, so I did turn it over! Strawberries will go in there now. Composting wood, or other plant material on the bottom of the bed is an old German technique. I have found that nitrogen seems not to be tied up, like you would think. All the beds have trimmed tree branches on the bottom of the beds.
When I put the corn stalks in millions of worms were in the bed. The soil is 1/3 peat, 1/3 compost, and 1/3 garden soil from bags over leaf and wood scrapes that line the bottom. Wooden sides are 12 iches wide. I use raised beds as we have wet springs, and also to control the PH. Sulfur is added to the beds. All plants pictured were planted this spring.

Drew, I use plenty of compost in my raised beds like yours, that are on the ground. I was talking about raised containers that have no contact to the ground.
I was told all of the nutrients would be washed out and to forget about compost and use time released fertilizer instead.
Nancy

I just use a garden pitch fork and till in any new compost,etc. a little bit into the old soil. It's easy with raised beds since the soil doesn't get compacted like normal ground soil. Stick & twist/lift is what I do.

Tom