Oh, no, lead! And it sounds like you really want to garden. You can use large containers, or line beds with a barrier that prevents root penetration. Old carpeting will do in a pinch.

For filler (for either) you can buy in bags, use 3 parts topsoil (cheap!) and 1 part composted manure (reasonable). If you would rather not use manure, just use "humus" or compost made from yard waste, and add a plant-based organic fertilizer.

The lead problem won't go away, so you might want to think in terms of doing a great job with large containers. Big plastic ones don't weigh or cost much, and you can grow a lot of stuff in them. Or, use big planters to structure outdoor living areas. It can work beautifully.

Here is a link that might be useful: my website

First, do you know for sure you have lead contaminated soil? Have you had a soil test done that measured heavy metals? Often, in areas that once supported heavy industry that did generate lead contamination, there is far more atmospheric and residual (surface) contamination than soils that are seriously compromised. And the lead problem can be made to go away. Biologically active compost is used extensively for bioremediation of all sorts of toxic and contaminated soils and it is cheap, relatively rapid and very effective. There is also no documentation that supports that lead in excessive levels is necessarily transported into the plant tissue and subsequently to you as the consumer of the plant parts. The greatest risk is exposure to you through working the contaminated soil and its dust or tracking it into your house, etc. So there is really no need for "bottoms" to your raised beds, although container growing is certainly an option.

Sterile potting soil is just that - it has been pasturized or heat treated to eliminate pathogens and is used primarily for seed germination. The "organic" component is the ingredients in the mix, often peat, sometimes bark fines or other, non-soil organic components. The microbes typically present in any OM have been killed off by the heat as well - the pasturization process doesn't distinguish between the good guys and the bad guys :-)) But that doesn't necessarily mean your seedlings will starve for nutrients. Seeds are plant embryos that contain all the nutrients necessary for germination and the development of the first true set of leaves. It is not until these leaves emerge and the photosynthesis process begins that seedlings are even able to access soil nutrients. And pasturization or sterile potting media doesn't necessarily eliminate nutrients - these elements will remain in place in some quantity regardless. Once the seedlings have started producing true leaves you may, however, want to start supplementing with a dilute liquid fertilizer to ensure they are getting everything they need. And it is at this point in time you can consider potting them up into larger containers with a non-sterile potting medium, as the greatest risk of damping off or other fungal problems that affect seedlings has passed at this stage of growth.

1. Sterile Soil mixes have been treated in some way, maybe heat, maybe a fungicide/pesticide, to kill off all the soil bacteria and fungi, good and bad, and is a dead soil. Since many of the plant disease this is supposed to prevent are air borne these potting soils do not really do what you think they will.
2. Lead does not move around in the soil easily, can be remediated by adding lots of organic matter, and is really only a problem for you if you ingest it so do not grow roots crops or wash them really well before eating them.
3. There is no good reason to make a bottom for a raised bed because that would change the drainage characterisitics of the bed so too much moisture, a problem, might be held in that bed.
4. No they are not used interchangeable. Manure is used to make humus which is the undigested organic matter left behind by the soil bacteria that are at work in your soil. The humus you buy in the store is compost, and more often than not it cost more money when that compost is labeled "humus".

When you make the raised beds you line the bottom with a couple of layers of wet newspaper thus creating a barrier between the existing soil and your new soil. I highly recommend raised beds / lasagna gardens. I put one in a couple of years ago and love it...so much so that a new bigger one is going in this year.

The US government's EPA says this about pathways of lead exposure:

How might I be exposed to lead?
Everyone is exposed to "background" levels of lead, given its widespread distribution. Possible routes of lead exposure include:
* ingestion of lead-contaminated water, soil, paint chips, or dust;
* inhalation of lead-containing particles of soil or dust in air; and
* ingestion of foods that contain lead from soil or water.

(source: Addressing Lead at Superfund Sites: Human Health)

The US Department of Health and Human Services's Agency For Toxic Substances and Disease Registry says this about lead in soil, under Foods and Beverages Contaminated with Lead; Production:

Production sources may include
* root vegetables uptake from soil
* atmospheric lead deposition into leafy vegetables (Mushak et al. 1989 as cited in AAP 1993)

And in the same document, under The Natural Environment:

* People may be exposed to lead in soils directly or by eating foods grown on lead-contaminated soils.

(source: Lead Toxicity -- Where Is Lead Found?)

Before eating food grown in soil which is known to be contaminated with lead, I'd suggest contacting the Lead Hotline at The [US] National Lead Information Center for their advice.

All the best,
-Patrick

I wouldn't eat a single thing that came out of a garden with lead contaminated soil. I'd grow flowers and I'd raise all vegetable growing beds up at least 12 inches above the ground. But first, I'd get a reliable extension service soil test for lead.

Hi urankhu, you wouldn't happen to live in Ok.around Pitcher would ya ? I live in Galena Ks. I have been doing raised beds starting with a layer of cardboard or newspaper then some straw & them either rotted cow doo or mushroom compost ( that comes from Ok. at the mushoom plant)& adding some top soil to it & it seems to work well for me.
Jan ")

chliol- that's fine advice for a very temporary "barrier", but you will notice that roots from most vegetables will go right through that newspaper. only very shallow rooted plants would stay above the paper.

urankhu- i would agree that you should consider large containers. you can even use a kiddie pool (with some holes for drainage)if your plants aren't extremely deep-rooted. you may find if your food plants are in containers surrounded by ornamentals, you will have a nice visual hi/lo effect.