raised bed gardening

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Having very heavy clay soil, we are considering building some raised beds next spring. My question, what can be used to safely build these with? I have heard or read not to use treated wood as some of the poisons might leach into the food. Is this true? If so, can ordinary wood safely be treated in some manner to keep them from rotting as fast? Or is their another material which would work better. I do not want to build them without some type of barrier to keep the soil in as I am afraid some of our "gully-washer" spring rains would wash it away! Thanks for any info you can give me.

-- barbara (barbaraj@mis.net), December 26, 1999

Answers

I use concrete block, and it works great. You can even grow in the holes, and use the holes on the north side of your bed to erect a trellis for your vining crop. I've also seen fallen logs used and replaced as they rotted and composted into the soil. Kind of tough to get much of a deep bed that way though. If money is not an issue, there are also recycled plastic "lumber" you can use. Again, much depends on how deep you need your beds to be. A semi circle , or half moon raised bed doesn't need support at all. The idea is that the middle of your bed is higher, and it tapers off as you approach the edges. Then, short rooted plants are grown on the sides, and longer rooted stuff in the center. Any way you choose, your beds should be no more than 4 feet wide so you can reach easily. Sue

-- Sue Landress (Sulandherb@aol.com), December 26, 1999.

Our beds are made of Redwood, 30" high so you don't have to bend over as far, they were here when we moved in. If I were going to build them now I would use plastic lumber. The taller beds take a lot of material to fill but we use peat moss compost, sifter soil, sawdust lime, blood meal, sand & buckwheat hulls.

-- Bob Henderson (redgate@echoweb.net), December 27, 1999.

Hi,Barbara, We don't use sides on most of our beds unless they are terraced beds built on a hillside.The more organic matter you have in the soil,the less erosion will occur.Also,if you use mulch on and between the beds you will have less erosion.our beds are only about 3- 4" higher than the surrounding areas,except for our manure beds which we use for heavy feeding crops like squash and pumpkins.For these we dump the winter's manure (goat) in a bed formation where we would like a new bed.If there is a lot of quack grass,we mulch over it ,after mowing ,with several layers of cardboard or newspaper.These beds are about 12-18" when freshly built and settle down to 6-8" in time.There is no erosion with these because we have all the straw and hay bedding in there too.The first year,we plant squash seeds right in that fresh manure.You will need to water them a few times.When they come up they really go!!You can plant earlier than usual,because the composting manure gets warm enough that the seedlings will not frost or be set back.Some of our terraced beds have siddes, but they are a hassle when you want to work up the soil.We use scrap lumber for these.I guess that you could line the sides with scrap metal,like metal roofing, but this would leave sharp edges and again,would get in the way.The thing about a really deep bed with sides is that they dry out quickly,and then when you water them,a lot of water runs out the sides instead of soaking in.You can also plant white clover between your beds as a fragrant pathway,and that would control the erosion.If the soil has plenty of fibrous organic matter and mulch,and you don't let it set bare without anything in it ,you may not need sides.The treated wood has arsenic in it.You are not supposed to even breathe the dust it makes while sawing,and the splinters from it are especially nasty.There are rot resisant wooods such as cedar,black locust,and osage orange,that you could probably use as log sides.Hope this helps.

-- Rebekah Leaf (daniel1@transport.com), December 27, 1999.

With our clay soils,I dug 3 4footx12 trenches knee deep and surrounded them with concrete blocks[cheaper than treated lumber and can be readily[but cuatiously-save the back !]moved. the 4 foot width allows easy access from either side.The beds are running north to south.I filled in the holes with a mixture of goat barn bedding and pond weed from my pond.I add:pond weed,wood ashes,and the contents of my compost heap each year[generally in spring].If I get lucky next spring I'll have a rototiller to stir it up.Early in the season will be time to put drip irrigation hosing[need to find a trash pump with at least 30ft of head].I fence the entire area with stock panels and chicken wire on the beds themselves[keeps the chickens from scratching up the seeds].Hope this helps.Karl

-- Karl Bechler (kbechler@frontiernet.net), December 29, 1999.

I also use concrete blocks but I use the more narrow variety, about 4 inches wide instead of the giant cinder-blocks. They are easier to move around. I started using them after my first raised-bed boards had rotted. They cost about the same intially but last much, much longer making them cheaper in the long run. But I must warn you that laying out a couple of 3ft.X 27ft. beds will wear you out, so get a hot bath ready and maybe a schedule good massage. One other advantage to the block beds is that you don't have to reassemble them every year. Just remove the end blocks and run you rototiller down the center (if necessary). After a year or two you will probably only need a hoe and a rake. Happy gardening.

-- Vaughn clark (vdcjm@ix.netcom.com), January 01, 2000.


If you can find a local sawmill, you can get rough-sawn lumber very inexpensively. We put up 12 4x8 beds for under $20, and used oak to do it. That was 4 years ago, and they are still going strong.

-- Connie Christoffer (litlgaea@cs.com), February 16, 2000.

If you don't mind rotting out every four or five years, use uderlayment cut into the size you want. My husband got a lot of this for free and cut them into 12 inch wide and 4 and 8 feet long. Each sheet provided the sides for 2 beds. Free is a very good price, and they are easilly removed. annette

-- annette (j_a_henry@yahoo.com), March 12, 2000.

Barbara our raised beds are all made with raised-seam roofing. They come in sheets that are 2 feet wide and 15 feet long, so you can cut these to any length. We just screwed them to small pieces of 4x4's and placed them on the ground. I filled them with compost and all of the rakings from our very large dairy goat barn. They are very fertile and prolific. It is amazing how much you can grow in these beds. I love the book Square Foot Gardening and I now totally disregard all of the statements about how far apart to grow things. With raised beds you also have very few weeds, and with beds 2 feet high, other than the occasional grass that does come up in a corner, it is so easy to weed. We also fight fireants, and just poison around the outside of the bed, instead of in with my plants. Make sure that your beds are only as wide as you can reach across from each side... Good luck! Vicki McGaugh

-- Vicki McGaugh (vickilonesomedoe@hotmail.com), March 12, 2000.

Having just bought my place last year, I'm only using mounds for my raised beds, but cinder block is the way I plan to go once I decide where I want my garden to be for the next few decades.

Erosion hasn't been a problem so far, but I mulch heavily with straw and grass clippings between my beds. Not only helps keep the weeds under control, but cuts down on the mud too.

With the block beds though, I've seen people put hardware cloth in the bottom of the bed to keep critters from digging down and under the blocks and then back up to get the veggies. And this same person ran a strip of copper all the way around the block to stop the slugs.

-- Eric Stone (ems@nac.net), April 13, 2000.


The best raised beds that I can find are old tractor tires, 10X20 size and some a little larger than that. I get them free for the hauling from the tire dealer (they have to pay to get rid of them). I then take them home and cut 1 sidewall out of the tire. I do this with an old lenolieum knife, I may have to stop and sharpen once during this process. Cutting the sidewall out is the hardest part. I then lay the tire flat with the sidewall that is still in place down. As long as the ground underneath is reasonably level there is no problem. I have some heavy clay soil that I put in the center. About 1 wheelbarrow full just to somewhat seal the bottom of the new tire bed. I then add some manure and soil to get the bed going. This makes a raised bed that will probably be here after I am long gone, no rot expected. "Works good, ought to last a long time".

-- Ed Copp (edcopp@yahoo.com), May 11, 2000.


Our raised beds are just mounds, with nothing holding the sides in place, and we haven't had any trouble with erosion. One of the previous respondents said that the organic matter in the soil would hold it in place, and I think that is correct. Our garden is too big to buy stuff to build beds with. Maybe someday if we have a smaller one we might -- I liked Vicki's idea of using the metal roofing, and the tire beds are a good way to recycle -- though I think in a hot area you might want to paint the outside of the tires white to avoid overheating the soil? In a cool area, the extra heat would be beneficial!!

-- Kathleen Sanderson (stonycft@worldpath.net), May 12, 2000.

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