should I separate the organic soil at the bottom of the raised bed from the "dirt" (no grass) that is currently there?

I think there must be some basic misunderstanding here about how organic gardening is done.

Why would you need to separate them? Do you know for a fact that it is contaminated with something? If so then that is a different matter, but the majority of folks who practice organic gardening do it in common dirt with lots of compost and other forms of decomposed organic matter mixed into it.. And 99% of the organic food you buy was grown in dirt too. Dirt is about as organic as you can get. :)

Organic gardening doesn't require some sort of special "organic soil" if there even is such a thing other than some of the marketing hype. Could you clarify what you mean by the term "organic soil"?

But no, if you create some sort of non-permeable barrier under only 7" then you will have difficulty growing deep rooted crops and you will have ponding of water due to the poor drainage.

Those who create raised beds for gardening will either 1) till up the soil where the bed will sit so that crops can grow down into it, or 2) if they have ground dwelling varmints place hardware cloth on the bottom to block varmint access while still allowing proper drainage and root access, or 3) use layers of cardboard to block grass growth while still allowing good drainage and root penetration as the cardboard decomposes.

Nothing wrong with the bed at Home Depot although it is expensive for such a small bed but its depth assumes it will be used on top of the open ground or that only shallow rooted plants will be grown in it.

Dave

What a sweet idea. Seven inches would grow short variety carrots, radishes, dwarf tomatoes like Patio or Red Robin, lettuces, peas, and edible flowers (if you can find organic ones). I'm strictly organic too.
Great gardening to your little one !

Thank you for your responses. I'm referring to packaged organic soils that supposedly have no chemical fertilizers. We're planning to use certified organic seeds and would like to keep the garden as chemical free as possible. I can't say whether the dirt in our yard is contaminated because we've only been here for a few years. There's no telling what the previous owner did out there. Round Up, etc. I'm thinking now of building a cedar frame rather than buying a kit. The stock cedar boards at Lowe's or Home Depot will provide a deeper garden for about the same cost.

It is your choice of course but I just hate to see someone go to the expense of using bagged potting mixes when it is so unnecessary. But if you wish be sure to find one that is OMRI Certified. The laws allow for many bagged mixes to claim to be organic when they are nothing more than bagged topsoil like you already have in your yard..

I can understand your concerns about what the previous owner may have used on the native soil but after 3 years anything used has long since dissipated. And even if it wasn't then simply mixing in a good amount of high quality compost will make it as organic as anything you can buy. 3 years of no non-organic applications to soil is all that is required for organic certification.

So the only real concerns with your soil would be anything you may have used over that 3 year period.

The issues of "organic seed" being really organic or not is a whole other can of worms. Labels and reality aren't always the same thing. :)

Dave

Here is a link that might be useful: Is Your Potting Soil Really Organic?

Hmmmm....might want to take that link with a grain of salt :-)

Being a retail purveyor of several different organic lines of garden and potting soils, I have yet to see one with packaging that reflects OMRI certification. On the other hand, there is a long list of them approved by OMRI, including two Miracle Gro products (which I assume the link was referring to, as Scotts/Miracle Gro are always considered the bad boys by the organic crowd).

Most home gardeners are not concerned with formal organic certification - that is a complicated process really intended more for commercial growers. Just being able to grow their veggies without concern for manufactured chemical fertilizers and pesticides is usually sufficient for the vast majority of household organic gardeners. With that in mind, pretty much any soil can be considered to be organic as long as it has not been treated with these products recently - most will have fully dissipated/broken down over a year or a full growing season. Or as the previous poster indicated, ample applications of compost will neutralize any residual effects very rapidly.

Unless you suspect your property was some sort of toxic waste dump - car repair lot, filling station, meth lab, etc. - or you live downwind from a smelter, there is not a lot of concern about the existing soil in your garden or incorporating that into your raised beds. However, that is typically not available in excess to fill raised beds and imported or bagged soil is the fallback. This is such a common occurrence and following organic practices in home gardens so prevalent, you really don't have much to worry about.

I agree with you completely gardengal and you made the points I was trying to make much better than I did.

I fear the OP has been misled by some of the "jump on the bandwagon" organic marketing hype we often discuss here. Those sources that would further line their own pockets by making the whole concept and all aspects of organic gardening much more complex and costly than it needs to be.

That said, IF the OP is determined to only use OMRI certified soil mix then it is advertised as available from some sources (Kellogg's is one that comes to mind). Are those sources reputable? Not IMO because despite their claims, what they are actually selling is no more "organic" than most of the other products on the market.

Dave

If you're mildly handy, and own some basic tools, home depot and lowes both sell cedar 1x6 fence pickets in 6' length for about $2.50 each. You could build a bed (that is 1" shorter than the HD $40) for $10 and have wood left over. (or go 12" high for $20)

Thank you for all of the suggestions. Today is a beautiful day, so I think we'll finally start on our garden project. I'm aware of the fact that we truly don't know what's in the soils or seeds labeled "organic." But, I'm looking to minimize the risk of chemical contamination, so I have to take reasonable measures to do so. It's definitely an interesting topic though. Does it upset anyone else that we can't buy food, seeds, soil, etc. without wondering what kinds of chemicals are in them? I guess that's a question for a different forum. Again, thank you for your responses.

The operative word is "reasonable" measures. That is sufficient 95% of the time. That percentage of seeds are chemically free, and that percentage of soil is also chemically free. So extraordinary measures such as you plan are very seldom necessary.

Dave

Drifter1019, you would be surprised at the amount of food you can harvest from a 4x4 raised planter. I've been successfully using squarefoot gardening principles for a few years now. My beds are simply cheap 1x6 fence boards cut to 4' and deck screwed together. On the bottom, I lay down some cardboard, fill with my homemade Mel's mix, and apply a mulch layer on top. Easy peasy. You can see a snap shot of my beds in the Going Organic! thread. All gardening is local so your mileage may vary,

Square foot gardening really got me going, as well. You will be surprised at how much you can grow in a 4 X 4 square. If your child is going to be fully involved, you may want to make the box 3 feet wide so she can reach the middle more easily. You may also want to start composting so you can provide your own fertilizer for the plants.
We had a little garden at school with 8 inch deep raised beds on asphalt. We grew lettuce, peas, radishes, broccoli, strawberries and mini-sunflowers.

Here is a link that might be useful: My square foor garden