I don't see how it would hurt, but don't know that it's necessary. If there are data that such a lining will increase the lifespan of the wood (but, most regular thin plastic will get "holey" after awhile), that might be a reason. A higher priority is likely the soil composition (too light or sandy and it doesn't hold moisture long), including something like the use of moisture crytals (whoa, I haven't researched those to know if make a big difference, especially re: cost) , and adequate mulching. Is your bed "built" on bad hardpan? That will take awhile to soften up and soak water--otherwise it runs out the bottom sides. Sometimes I use a combination method, in which I'm mostly trying to do no-till raised bed due to my rocky clay soil, but maybe take my pickaxe to the soil surface and try to mix it up for a few inches (not enough for planting directly)in the hopes (?) that that will provide some additional moisture reservoir and worm action.

I was thinking of building it now, and just dumping in the partially composted stuff already in my compost bin. This would free up the bin to start filling again with my most recent scraps and other materials. Even simpler ... dump the old plants and whatever is in the compost bins into the new raised bed, along with whatever else you can scrounge. Cover with some dirt, and mix it in the spring.

I saw that show, it was good. Paul James demonstrated this in just a couple of minutes. It's nice, especially for people, who, unlike us, don't hang out on soil forums with compost wackos. Of course that's meant as a term of endearment to my friends here. Most foks who want to undertake a similar project would, I think, build the frame then buy topsoil. Or hire a landscaper to do the same. Karen

I found surface bond cement worked quite well, and was fairly easy for a first time user. It did not require leveling every block. Just level your ground and dry stack your blocks, and spread it on the outside/inside. Quickrete, and sakrete both have a version that is available and Lowes and Home Depot. http://www.quikrete.com/ProductLines/QuickwallSurfaceBondingCement.asp http://www.sakrete.com/products/detail.cfm/prod_alias/Surface-Bonding-Cement I would (did) use full size blocks 8X8X16 they are not that much bigger and you can grow lots of stuff in the blocks. I have strawberries, Garlic, and about every herb doing quite well. There is a pretty big jump in stress adding the 4th row. I would discourage the 4th row (32"). Unless you have a level or solid footer, or plan on using mortar to help level it out. The flaws get magnified with every row, and for my dry stacked blocks the 4th row was really tough to get level. For my gardens the 32" garden has seen settling and winter/summer cracking. My 24" 3 row stack gardens have not. As for reinforcing the walls maybe pour the corners solid with reinforced or fiber "crack resistant" cement. The ready mix cement is not the difficult to mix, just add water and mix until it is workable. After completing my gardens I had to ask myself how much am I going to save my back by having high raised beds Vs. the gardening on the ground. I think in another 10 years I will break even. Though in my area the raised beds have worked wonders at keeping the bugs/ nematodes away.