I like a combination of fine redwood bark (sold as mulch), home made or bagged compost, and clay cat litter or Napa Aui\to Parts Oil Absorbent (part #8822). You can read more about the mix on the container forum. Roots grow best in the intersection between water and air and a chunkier mix with good water retention encourages healthy root growth and everything else follows from that. I kind of stumbled into the mix of chunky stuff years ago. For years I used chopped garden waste along with compost and clay cat litter, but getting the right mix of garden waste that would last an entire season without completely breaking down was always hit and miss. Then I stumbled on Al's information on the container forum and the redwood bark which is cheap here in California turned out to be a great replacement. I've just started experimenting with the Oil Absorbent in place of cat litter. The peat moss and vermiculite additions are not very useful although they are traditional. The peat moss is hard to wet and doesn't provide for the light, porous mixture that promotes root growth (and is not a sustainable choice, either). The vermiculite breaks down very rapidly so that it provides little value and is quite expensive to boot. Additionally, I dump leaves and clippings between the plants to compost in place and dump kitchen waste into small holes that I make in random spots. My tomatoes grow to about 14-16 feet tall (there's a pergola overhead for support), so I must be doing something right. Here is a link that might be useful: Al's Container Soil

Permeable means it s ability to allow liquids to pass through. Chicken wire is fine if you have moles/voles but landscape fabric is only mildly permeable. Testing consistently shows it slows drainage substantially. It is not ever recommended for the bottom of a bed by experienced gardeners and it would have no effect on the moles and voles anyway. 75:25 compost:loam is high on the compost side and the quality depends on your definition of "loam". Means many different things. But as long as it isn't so-called "top soil" or sand a 50/50 mixture of it would probably work. More commonly you see the recommendation for 40:60. But you will have to add more compost at least once a year and better 2x a year as it continues to shrink as it decomposes. I get the impression you aren't interested in first trying to improve your native soil and incorporate it into the bed, correct? That is the best route to go. But if not then you need to understand that overtime it can affect whatever you fill your bed with unless you made some sort of solid bottom box which is not at all recommended. But you can still make it work with a framed raised bed on top of it with chicken wire or hardware cloth on the bottom IF you keep the bed well and frequently amended with quality compost. Over time the leachate and soil bacteria will improve the soil below the bed as well. Dave

So we finished our new raised vegetable beds and thought I would update this thread. We ended up having only enough soil from our old beds to fill two of the new raised beds. We also used all of our store of organic matter, which wasn't a lot and compost dug out of a passive compost pile that had been there for over a year which we used to fill the bottom half of those two beds with the soil from the old vegetable beds for the top half. Then we had three beds still to fill! I seriously considered making up a mix using pine bark fines etc., but reading along, what jumped out at me was the percentage of organic matter that is recommended in your native soil. In our old vegetable beds, I added a lot more organic matter, maybe up to 50% and the soil would shrink back and I'd have to keep adding more every year. So, in the end I decided to at least check to see if I could find some 'organic' native soil to purchase. I called around for recommendations and someone did direct me to someone who might have what I needed. And they did. They also added a small percentage of organic compost and had amended the soil with organic amendments, like alfalfa meal and worm castings etc. It sounded like just what I wanted. So we had them deliver it and filled the remaining beds. I will be interested to see how the produce does this year and compare the old soil we had, with the new soil. The new soil is also clay soil, and it doesn't drain as well as my own soil or the soil from the old vegetable beds with all the organic matter, that water just runs through. This new soil, the water puddles on the top for a little bit, but a layer of mulch slows it down enough. I hope to amend the new soil, either with cover crops or mixed lawn clippings and chopped leaves in the fall. So that's the end of that story. Thank you all for all the help and answering so many questions. :-) The last bed filled with new soil.

I'm fairly new to this forum altho have gardened in various ways for many years but your post brings some questions to mind. I'm curious about the size of your "garden" - will that be large enough for the plants you are planning? I find that quite a small garden and would probably use those 2'x10's and make 3 raised beds which are not so tall. Unless your base is pure bedrock you won't need more than 8" of good soil for most plants. If you loosen the base with a fork it will improve over time. Of course there may be another reason you want to elevate the garden to make it easier to work but you really don't need IMO to have 28" of good soil. If you have any reasonable soil you could fill the tall bed with greens and browns mixed with soil and top it with 8"-10" of good soil, whatever is available. Any worms in the soil will have a feast. If you start a compost bin ASAP you will have some good stuff to topdress your garden in a few months. I've rarely come across bagged soils that are all that good at a low price, and I think it might be a pretty expensive way to garden if you buy that much at high prices. Better to buy some organic fertilizers to supplement until you can get that compost done.