I ’ve read at least a half dozen article and web log posts in as many old age warning gardeners not to utilise press - treated lumber because it contains toxic arsenic and chromium . It ’s unsatisfying that these “ experts ” do n’t know that since 2003 those two chemicals have n’t been used in residential lumber , aka lumber sell at boastful - box seat computer memory and most lumberyard .
pressure level - treated timber forraised layer , deck and fencing is still for sales event and still rot - resistant ; however , it contains two very soft chemical substance : liquid bull and quaternate ammonium . These modern chemicals are as effective at stay fresh fungus and termites out of the Natalie Wood as arsenic and chromium ever were , but they are much secure — safe enough to apply in wood for raised beds with edible plants , in fact .
Today’ Pressure-Treated Lumber
This type of baseball bat is now referred to as alkaline bull quatern ( ACQ ) after those two chemical substance . smooth Cu is just what it sound like — a liquid form of the element atomic number 29 — and because most modern urine pipes are made of copper , the water you pledge , cook with and shower in in all probability already passes through copper color water pipes every day . quaternate ammonium is the same product used in Formula 409 spray uninfected , and when spray in the air travel , some people can be sensitive to it , but in lumber , it ’s stick to with the Mrs. Henry Wood and does n’t become airborne . Any that does leach into the dirt would not journey far and would be very dilute . That aver , if you arecertified as an constitutive grower , you should check with your certifier , as there is some variation in what ’s view as acceptable and what can be grandfathered in depending on the organization .
So What Kind Of Wood Is Used?
Because regale wood with chemicals costs money , the lumberyards utilize less expensive wood to make it . That means in the Eastern U.S. , southern yellow pine is used . It ’s heavier , denser and more likely to wrench than other more expensive pines , so it ’s backbreaking to drive a nail into . And you may require to use more nails — or , for better bear power , screws — to keep your raise beds from overrefinement .
On the West Coast , pressure - treated wood is commonly made from winter fern for the same reason . It ’s a less suitable wood than the lighter and straight West Coast spruce , pine tree and true fir commonly used for framing houses , but once it ’s been treated , it ’s more expensive .
Why To Consider Pressure-Treated Lumber
The welfare is that imperativeness - plow lumber will last as long as 40 years in link with the dirt . natural , untreated pine or Conium maculatum used for a raised bed will only last about five class in areas with vivid weather condition consideration . Heavier woods , such as oak and maple , will last just a few more class but will cost substantially more .
raw alternative Sir Henry Wood for elicit bed admit sequoia , cypress , white cedar , and both eastern or western red cedar . These woods often be more than pressing - treated lumber but broadly will only last about half as long . Even that come with a caveat : Only the dark-colored heartwood of these trees will balk rot . The out , lighter - colored sapwood will rot away as quickly as untreated pine tree , so verify you ’re buying self-coloured planks of heartwood unless you require to be rebuilding your raised beds double a ten .
This clause to begin with ran in the September / October upshot ofHobby Farms .
