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raised garden bed

Can anyone please tell me if it is truly OK to use Pressure Treated Lumber for the structure of a vegetable garden bed. I was always told not to use it, due to the fact that it was not safe, but now I am being told that this it not the fact anymore. I just want my family to be safe. So the question is, can i use pressure treated lumber safely or should I get ceder (or some other type of wood that can stand up to the elements) thanks.

A. Spruce
Re: raised garden bed

While it is true that the formulation of preservatives is not the superfund concoction that it used to be, it still isn't anything I'd want my food near. You are better off to use rot resistant wood species or masonry. What you want to look for are woods with a high tanic acid content, such as redwood, cedar, spruce, and others. You can use Trex and Trex-like products, though those products are made with recycled plastics, plastics which do leach into the soil.

Masonry is also a good choice, but you must be aware of it's origins as well. In the states that use a lot of coal for power generation, the fly ash residue is used in the making of cement products. Fly ash is high in mercury and other toxic compounds which are not safe or fit for consumption.

Bottom line, if you're looking for a healthy and green way to build raised beds, you want to use natural products. If you use synthetic products, be aware of what is in them and what would be imparted into your food chain.

Re: raised garden bed

Generally you don't want your raised beds to be more than 4" high, lower if you live in the south. Just make the beds with dirt sides. Using a structure material like wood or masonry will just get in the way if you want to till.

I sometimes use wheat straw bails to make a taller raised bed for tomatoes. I till an area about 6x16, mound up the soil in the center and make a 4" deep trench around the perimeter, wide enough to accommodate the 12 wheat straw bales. Then I level the dirt in the middle, add a few amendments, rake it in and plant a dozen tomato plants. As they come up, I add shredded leaves or more wheat straw until it is level with the tops of the bales.

As the season wears on, the wheat straw and leaves break down and feed the tomatoes. At the end of the season, I just let it over winter as is. I can plant something like squash or corn in the bed the next year with almost no preparation. Its usually good for another year after that.

Re: raised garden bed

When I first started gardening at this house about 20 something years ago, I was faced with heavy clay, farmed out soil. The first couple of years, I was only able to till down about 2". My garden was about 20x60 then. I would till the whole area and then mound up the soil from the paths into the beds giving me about 4" deep beds to work with. I made the beds about 4x16 with 2' paths all around. I would add what ever amendment I could afford at the time to the beds.

As the soil improved with winter covers of winter rye and either buckwheat or harry vetch, I began to only till where I intended to plant and let the paths go. I would mow them, but thats all. Currently that is all I do, except that I will make a special tomato bed using wheat straw bales as I mentioned above.

I will attach some pictures in case you are interested, but I warn you, it looks a lot easier than it is. I did a double bed yesterday, first time I've done that and that is why I'm stuck on the computer today.

I dug the trenches about 4" deep for this one.

Back when the soil wasn't so good and I could only go about 2" deep, the bed would look like this.

As the tomatoes grew, I would add leaves and loose wheat straw to fill in. By early summer, the bed would look like this.

The wheat straw bales would start breaking down by this time. I plan on using the tops of the wheat straw bales to walk on between the beds this year but that may turn out to be tricky as the wheat straw breaks down. Just hope I don't break a leg trying to walk on it.

A. Spruce
Re: raised garden bed
keith3267 wrote:

I was faced with heavy clay, farmed out soil. The first couple of years, I was only able to till down about 2".

That's what they make tractors for. :p:cool:

A couple years ago when I started refurbishing the soil in our garden, like you, I could only get a couple inches in the hard pan clay. The key for me was to till while the ground was still soft from winter rain. After a couple passes with a mid-tined tiller - not a tractor drawn one - I was down about 6" or so. From there I layered on 6" of horse poop and tilled that as deep as I could get the tiller to go. Once that was done, another 6" of poop went on and wintered over. In the spring I was able to relatively easily till to about a 12" depth. Garden went gangbusters that year. That fall another 6" of poop, all tolled about 20 yards in all over about 18 months.

Today, the entire garden is so soft and pliable that you can dig it with your bare hands. Nutrient levels are right where they should be, whereas before they were non-existent. I'm a big fan of organically amending bad soil, and just how quickly bad soil turns around.

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