My raised beds were filled with a third being peat moss. A third being vermiculite (perlite would work as well). The final third was a combination of different soil mixes. Bags of compost, Miracle Grow, manure, Scotts...Some of everything to get a good combination of nutrients since different companies use different ingredients. I've had great success with this combination.

Here is a link that might be useful: Kim's Garden

Rather than buying bagged mixes it is usually cheaper to contact local landscapers and buy in bulk from them. They will usually offer at least a couple of different grades of mix. Don't buy without seeing it, smelling, it, and running it through your hands first.

But a mix is what you want for best results. Keep in mind that you are basically dealing with just a BIG container so it has to be well-draining, light and airy, and contain a good level of nutrients. Plain old dirt or garden soil isn't going to meet those criteria.

Over on the Soil & Compost forum here you'll find many discussions on mixes for filling raised beds. You can make your own easily and recipes vary from 1/2 compost and 1/2 soil to 1/2 peat, 1/3 vermiculite, and 1/3 compost. The latter is the standard Square Foot Gardening Mix - check their forum too for many other recommendations.

Dave

Hey thanks! I always learn than diversity works in most situations, so this is great. Had NO idea there was a soil and compost forum here :-) so I'll go search and post there.

We've usually gone with teh "plain old dirt" approach with our garden and have had mixed results, a best.

Oh, and my boxes are 4' x 2' x 1' deep. So I have 1' to work with. Do I need some sort of weed block at the bottom or should I leave it for better drainage?

Very excited to get started - Thanks!

I use 100% home made compost. If you use 1/3 peat, 1/3 vermiculite then 2/3 of your mix will have zero nutrients. John

Here is a link that might be useful: John's Journal

bheron,
What worked well for all of my raised beds was a layer of newspaper covering the entire bottom. Probably 4 or 5 sheets thick. It'll remain intact long enough to sufficiently kill the weeds or grass underneath, and it won't hurt the environment. It will eventually decompose and won't interfere with drainage. Worms will be able to work their way through it to help keep the soil aerated as well. I've used landscaping fabric in the past as well, but I figure the newspaper will eventually decompose and allow for the roots of my plants to grow even deeper.
Kim

Here is a link that might be useful: Kim's Garden

I buy it either at the county landfill where they make compost or at the landscaping place. We buy by the truckload when were starting new beds.
I usually get a free load of horse manure to put on the bottom, then fill with the "bought dirt". After that I top with my own compost each year. It's a LOT cheaper than buying tons of bags at the big box store! It works for me!
They might even deliver for a fee. Nancy