I looked into this before building my beds and what I found was that most of the treated wood these days is not treated with the toxic chromium and arsenic that was used in the past. Supposedly, they are today treated with mostly non-toxic substance but I can't tell you what that is. I never went that far into it. I have difficulty believing that somehow, the trace amount of chemicals that may leach out of the treated wood are going to be transmitted into the flesh of various vegetables any more than substances contained in dog, cat, or horse feces is transmitted through the root system and into the fruit, leaf or vegetables. I suppose root crops could possibly absorb some amount through direct contact if concentrations were high enough but still, I find it hard to believe that it would absorb more than negligible amounts. Considering all the added unnatural chemicals/preservatives/dyes etc, we consume daily in our food and beverages, not to mention everything we breath, I concluded that, for me and my family at least, any chemicals in treated lumber is a non-issue vs. the benefits of eating fresh vegetables. YMMV

Nathanhurst: Would you like to share your data? I have the same data as you or Stuart or most anyone else these days. It is the information on the web that I researched and reviewed that lead me to my decision to use ACQ lumber. My job involves understanding the degree of risk posed by constituents like metals and pesticides in the environment. When I was looking into ACQ I needed to look beyond the leaching studies that just focus on the copper concentration of ACQ leachate, i.e.: ".but it(ACQ) does have triple the amount of coppera substantial increase." I can agree with that quote to a point. But just because it leaches doesnt mean it is bio available. In the current dialogue, your premise for copper being a concern appears to stem from the mere fact that copper is present in ACQ leachate, period. What appears to be missing is an understanding of coppers fate and transport in the soil from its source (ACQ leachate) through the soil column to a receptor (a vegetable plant root system), the resulting exposure concentration (copper in a tomato) and the frequency at which tomatoes are consumed by the ultimate receptor (us). Soil organic matter, silt and clay particles, cation capacity all serve to attenuate, minimize or limit the migration of copper in the environment. For me, the data supported no adverse risk My statement was used out of context in your response since it did not include "under my garden use and consumption scenario". The latter text is where fate and transport and receptor exposure concentration come into play to describe the actual risk posed by copper. I can find articles calling ACQ into question without even trying (the first hit on google with ACQ): "Though this preservative mix has proven to be the most effective so far, ACQ poses its own concerns. soil and sediment. ACQ doesnt have the arsenic or chromium issues of CCA, but it does have triple the amount of coppera substantial increase." -- http://www.nadra.org/industry_news/acqarticle.html (and that from a body trying to promote ACQ use!) For someone who takes that statement at face value, they would believe it to be a case against ACQ unless they looked deeper into the source. NADRA is the North American Deck and Railing Association whose mission as stated on their website is to "promote outdoor living at its best, in safe and creative environments for the enjoyment of every homeowner". They are not promoting ACQ use anymore than they are promoting redwood or composite decking. The article mentioned is at best a third or fourth order source for ACQ info since its author, a fastener manufacturer, was discussing the compatibility of decking screws with ACQ chemistry. NADRA was however providing it members and web surfers a service by mentioning the ACQ copper study so the user could make their own informed decision. Saying that quaternary ammonium salts are the same as ammonia demonstrates a lack of chemistry knowledge and makes me doubt the rest of what you are saying. True, I am not a chemist but I did pick up a few things from my organic chem, inorganic chem, biochem and geochem courses. However, I was not specific enough. I referenced quaternary ammonium compounds in general when I was specifically thinking of DDAC, the quaternary ammonium compound used in ACQ. DDAC is an anti-microbial compound also found in household disinfectants, laundry detergents, fabric softener dryer sheets and swimming pool disinfection to name a few. My point in mentioning it was that DDAC is more common as an active ingredient in products we touch, breath and swim in everyday. As good gardeners we all know that AMMONIA found naturally in high concentrations in raw manures will burn a plant until soil microbes convert it to nitrate, the nutrient plants need. And IF we add too much nitrate-based fertilizer it can leach to groundwater. And IF it reaches a groundwater concentration greater than 10mg/L it can produce methemoglobinemia or "blue baby" syndrome in infants. Organic animal manure. Copper poisoning is not pleasant, I've had it. Having experienced copper poisoning first hand its understandable you would be cautious of any product containing copper. Comparing with copper pipes is like saying that sarin nerve poison is harmless because its got carbon in it. My plumbing analogy was to point out that receptor exposure concentration (trace copper) and duration (a lifetime of daily drinking/bathing) is equally important in determining risk in addition to the mere presence of copper. Few folks would list pure drinking water as an acute toxin, yet last year in California a young college student died tragically in a fraternity hazing incident by drinking too much water (not alcohol) in a short period of time. The water essentially diluted the electrolytes in his blood and he died of a heart attack. Pure drinking water. There is a lot of information on the web. Some confusing, some misleading and some conflicting especially when it comes to an emotional topic like human health. I offer my opinion in response to a question by dgriff as to what to make of ACQ. This was my personal decision, based on my review of the literature and my professional experience. Were I a Wall Street type, I would offer my personal perspective on a financial web forum to a non-financial type who wanted to sort out conflicting info about different investment products. Ultimately, its up to the individual to glean what they can from the various experiences expressed here and make an informed decision they are comfortable with.

I'd put the bed outside the drip line, if there is one. Leave enough room between the bed and the wall so you can easily rake debris from there and work on that side of the bed. A 5- 6-foot wide planted strip is about as wide as you can easily work on without having to climb in with the plants. You could have a 6x40 strip of veggies with working paths all around. Don't worry too much about having to improve the dirt. This picture shows the first year of growing anything in unimproved North Phoenix desert dirt on this side of my house. The key is that there is a drip irrigation system (2 rows of drip tubing running between 3 rows of plants) under a thick layer of rough compost and shredded tree prunings. I scattered liberal amounts of soil sulfur and a small amount of ammonium phosphate onto the dirt at the start. The sulfur unlocks some of the iron and lowers the pH a bit, and the phosphate was a "just in case". Then I dug a small hole just big enough for each transplant, filled it with water and let it drain, transplanted, back filled with local dirt, gently tamped the dirt down and soaked it again. Then I covered the dirt with a 2-4 inch layer of compost and covered that with a thick layer of shredded tree bark. This picture shows what you can do with just the watering system and the coarse mulch, no added fertilizer or compost at all. If you have that much room, dedicate some space to composting things ... http://www.associatedcontent.com/article/1447458/building_a_cheap_wire_compost_bin.html explains my no-turn bin method. If you fill a bin, run a drip line to it and use to grow tomatoes for a season, then break it down and spread it. This one holds the too-coarse stuff from several bins I broke down this spring, with some cherry tomato plants.

CCA treated wood has been off the market since 2004, so that is no longer an issue. And there has been no significant scientific documentation to support the notion that CCA-infused lumber leaches excessive amounts of arsenic into the soil anyway - modest levels of arsenic tend to be present in most soils. Raised beds do not have to be created from lumber - inexpensive concrete blocks work just as well and can be assembled into raised beds and disassembled at will. Or use recycled concrete chunks, often available for free. And using these or any recycled wood products like Trex eliminates any rotting issues as well as any insects that may be attracted to wood. Slugs are slugs and in the PNW they will be present regardless of planting situation - in ground, in raised beds, even in container plantings. Baiting will control the worst of the slug damage in any case. Any mounded or raised planting area will require at bit more frequent watering than inground or nonmounded/bermed areas - that is just the physics of drainage and water movement. There is nothing specific about constructed raised beds that would make them any more higher maintenance than mounded or inground row plantings other than the use of materials and even untreated cedar or redwood will last 5-10 years before needing to be replaced, longer if they are lined with plastic to limit contact with damp soil. And problems with cultivation is a non-issue. Once they are filled with soil, additional cultivation in the way of tilling is seldom necessary and generally not recommended anyway. Additions of compost or other OM can be made easily in the offseason or before planting. There is no need to disassemble a raised planter to renew or refresh the soil. We all have our preference on what we like best, but there is nothing innately inherent regarding constructed raised planters that makes them less desireable than inground plantings other than personal choice.