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RAISED BED VEGETABLE GARDEN Karyn P. wrote: I don't think that creosote does much seeping. It wouldn't be a very good preservative if it did. And judging by the height and robustness of the weeds that grow around the creosote-soaked telephone poles on my property, I wouldn't worry that it would harm the veggies, either. More specific counter-anecdotes welcome. --Mark Amidon > Living on top of a hill like I do, I have approximately 1 or 2 inches of soil before hitting rock ... So I need to build a 8+ inch deep raised bed garden to plant my veggies in. You almost certainly need more than that. Most vegetables really want a few feet; tomatoes conventionally use something like 10. Some varieties are bred for containers and need lots less; check the details. I would shoot for 12-18" tall. Another alternative for materials is that recycled-milk-bottle plastic 2x4 that they make some park benches and nature-refuge walkways out of. It _should_ be cheap; it will definitely last; environmentally friendly. They flex, though, so you'll need some kind of cross bracing. When laying out your plots, consider how far you have to stretch to reach the interiors. If you make 6x6' beds, you will probably end up walking around in them, while 3x4' beds leave easy access. And take more materials. Make 2, 3 or 4 of them, with walkways in between. -dca > pps: anyone know where I can get a whole lot of topsoil/good dirt cheap? Gotta fill this with something. You can start composting now; the containers for that bear a remarkable similarity to raised garden beds. I've seen roadside signs for screened loam, but I have no idea how expensive, or what delivery would be like. Concord has a huge pile of "free soil" at the dump by Walden Pond, but that might be for residents only. And you'll have to shovel it all; I expect that limits the rate at which people take it. They run a leaf-and-brush dropoff, which I suspect is where the loam comes from. There are lots of good books on container / raised-bed gardening. Visit your local library. -dca Organic Gardening magazine did a comparison of several lumber-like options for building raised beds. Their conclusion about treated lumber (after testing it and measuring arsenic concentrations) was that the arsenic in the lumber does move into the soil. I would suspect that the creosote in railroad ties would, too. Railroad ties, in their native habitat are in extremely well drained beds of course gravel. That is very different from having them essentially buried. There were some railroad ties in our garden left over from previous occupants, and I can tell you that they do rot. Of course, I have no idea how long they've been there. What else do they put in those things? Is it just creosote? In the absence of other information, I'd assume any number of noxious petroleum by-products. The conclusion from Organic Gardening was pretty grim for budget minded folks building raised beds from lumber. Treated lumber was really the only thing economical enough that would last for a few years, but was unacceptable because of arsenic mobility. The new type of treated lumber that doesn't use arsenic (I forget what it is called) was far more expensive, but lasted longer. Then again, there are concerns about the chemicals in that leaching, but it is certainly not as severe as standard PT lumber. The most "eco-friendly" option they had was to use Trex, which is stuff that looks like lumber but is made of recycled plastic. It lasts a long time, but is really expensive. The article also goes into several types of wood that are naturally decay resistant, like redwood, and some type of pine (Southern Yellow??). Meg and I just built two raised beds out of the limbs from two old, nearly dead apple trees that we just cut down. We still haven't figured out what to use for the rest of our beds. Of course, there are two or three other trees that we want to cut down.... Last weekend was the first time I tried cutting down a tree without a chainsaw, I'm amazed at how efficient the hand-held bow saw was. I'm now convinced that if I cut down 2 or 3 trees per year, the bow saw is, overall, less work than a chainsaw (including maintenance, purchase price, etc.) --scott PS Meg and I received and planted our two Paw-Paw trees last week!! Another alternative for materials is that recycled-milk-bottle plastic 2x4 that they make some park benches and nature-refuge walkways out of. It _should_ be cheap; it will definitely last; environmentally friendly. They flex, though, so you'll need some kind of cross bracing. --Dave Anderson Trex. --dca Trex should be cheap, but it isn't. They just can't match the volume sales of regular lumber, and probably won't for a long time. Normally, you can take care of the flexure by putting vertical stakes in the middle of the outside walls. But if there is only two inches of topsoil above rock, I suppose that wouldn't work very well. Maybe buttress type supports? --scott > PS Meg and I received and planted our two Paw-Paw trees last week!! Oh, well, if you're talking about planting hardy fruit and nut trees in the western Mass area, I would be remiss in failing to mention my friend's nursery. The catalog is at http://www.sln.potsdam.ny.us --russ nelson > Trex should be cheap, but it isn't. I get the picture, although I suspect that here, "cheap" is relative. Getting the dirt in, for instance, could easily be a lot more time (is money) than this. Anybody have a figure for the price? > Maybe buttress type supports? I was picturing a vertical "stake" outside the cross pieces on the long sides, held together with some steel wire, or stainless cable if you want to get fancy. That presumes vertical walls, which as Crash pointed out, isn't necessarily a given. -dca Well, it turns out the article I read was in Kitchen Gardener, not Organic Gardening. I found it online. This doesn't include the arsenic mobility stuff. Trex is even more expensive than Redwood, and more than twice as much as standard pressure treated. I also found that there is a competitor to Trex called ChoiceDeck, and that Trex has recently had an IPO.... I called several Connecticut lumberyards to see what was available and how much it would cost to buy 24 board feet, enough to build an 8 ft. by 4 ft. raised bed. I've listed the lowest price I could find for each material. Stock is 2x10 unless otherwise noted. Local availability may differ. The years of expected service are ballpark figures, and could be lengthened or shortened by climate. 1. CCA pressure-treated wood-- $33. More than 40 years. 2. ACQ pressure-treated wood-- $38. Longevity similar to CCA. Look for the new ACQ Type D with built-in water repellent, and buy only wood with a retention rate of 0.40 for ground contact. As of this writing, there are only about 170 dealers in 21 states, with good distribution in Massachusetts, Minnesota, and Wisconsin. If you're interested in ACQ but can't find a source, ask your local lumberyard to start stocking it. For dealer information call 704/522-0825. 3. Redwood-- $62 for construction heartwood grade. 15 to 25 years. Heartwood is where the rot-resistant compounds are concentrated. Avoid construction common grade, which contains sapwood, and like any non-durable wood, would last only a few years with ground contact. Construction heartwood is primarily a product of young-growth timber, not old-growth "guilt wood." 4. Western red cedar-- $76 for knotty cedar. 15 to 25 years. Only one place I called had knotty cedar; most carry only high-quality clear grade, which is too costly for garden use. 5. Cypress-- $36 for a 12-in.-high bed made from 1- 1/2 x 6 decking stock. Longevity of first-growth cypress is comparable to CCA; second-growth cypress is moderately decay resistant. Cypress grows in the southeastern U.S., particularly along the coast, in wet, swampy conditions. A compound called cypressene gives the wood its admirable rot resistance. As with other durable species, look for heartwood. Not widely available outside its range, but at least one source, The Wood Cellar, Ltd., of Savannah, Georgia, will ship anywhere (800/795-9114, www.woodcellar.com). Call the Southern Cypress Manufacturers Association at 412/ 829-0770 for more dealer information. 6. Trex-- $88. Trex is a manufactured lumber product made from waste hardwood fiber and reclaimed plastic grocery bags. It carries a 10-year warranty against decay, splintering, or cracking due to weather. Trex has been on the market only nine years, but in accelerated-age tests it racked up an expected life of at least 28 years. It has a dense, even texture and is heavier than wood. Hot weather may compromise rigidity, due to a plastic content of about 50% and a lack of continuous wood fibers running the length of the boards. A company engineer recommends reinforcing the long sides of a raised bed by placing stakes every 2 ft. or 3 ft. to prevent bowing. Call 800/289-8739 or go to to www.trex.com to find a dealer near you. Check out the locals--Depending on where you live, you may have access to a native species whose heartwood is decay resistant. Black locust, red mulberry, osage orange, and Pacific yew show outstanding longevity. Other highly rot-resistant species include catalpa, Arizona cypress, juniper, mesquite, and several oaks, namely bur, chestnut, Gambel, Oregon white, post, and white. >Normally, you can take care of the flexure by putting vertical stakes in the middle of the outside walls. But if there is only two inches of topsoil above rock, I suppose that wouldn't work very well. Maybe buttress type supports? Bucky Fuller solved this problem a long time ago. Remember, a geodesic dome doesn't need a bottom. It _also_ doesn't need a top. --Crash i've done just fine with cherry tomatoes in a 12" kiddie pool. --vicka, who thinks zoo scenes are cute :) Cherry tomatoes are quite amenable to containers, but most other tomatoes aren't. I was just saying, look before leaping. -dca Any thoughts as to making a sunken bed garden instead? What's the preferred way of removing a bunch of rock? (What kind of rock is it?) At the least, you won't have rot problems... --andrew Guessing from the location, it's probably classic New England "Pudding Stone" (sedimentary rock formed by glaciers). Looking out the dining room window of my parents' house at the rock wall you can see where holes were drilled and concave areas where the dynamite exploded to make room for the house. The house is 100 years old. ---Ben and then ben referred to dynamite. I think I'd prefer a raised bed rather than dynamite. With a raised bed, you get *some* drainage, and if I do it right, a places to sit and eat with horizontal surfaces for liquid and food plates. I'm currently considering concrete blocks. Home Despot has 5 options:
I think I'm leaning towards the 6x8x16. Now, the question is, when you use concrete blocks, do you normally put the holes vertically or horizontally? I figure if I do it horizontally, critters like mice might live there, and I don't like that idea.. but lining up the holes horizontally gives me 16 inches of depth, which is desirable. and how do I deal with corners? Don't I have to offset the bricks if I stack them? And, will the concrete blocks be enough, or do I need some sort of support to keep them from falling off each other? I figure I can put a slice of pressure treated lumber on top for a seat and stuff, as long as I don't put the dirt up that high. But I haven't done the math for how much garden will cost. Seems like about 4 feet or so is the max width, so I don't have to step in. --karyn I'd go for the standard 8x8x16 and lay them lengthwise, holes up, then you could fill the holes with gravel or dirt and put little flowers in there too, filling the holes would add stability but it would probably be fine either way. Offset the bricks at the corners, or if you really don't feel like doing that much planning just fill in the short corners with 8x8x8's, but offsetting is more stable. There's also a kind of block that's specifically made for being laid dry and backfilled with dirt like this, it's kind of angled and lumpy, with interlocking bits, I forget what it's called but my folks used it for a flower bed and liked it. Each block sets back from the one below by a half inch or so, and I think there's a little overhanging bit on the bottom or something so they interlock. --Liz >and then ben referred to dynamite. Serendipitously, I happen to have just gotten the "facts on blasting" pamphlet from my town hall, and, though checking references is advised, it appears that this would be totally impractical. >I'm currently considering concrete blocks. Home Despot has 5 options: Serendipitously^2, I was also at HD last night pricing concrete blocks. Aside from the holy options you list, there are a number of solid blocks available, at least at the Tewkesbury HD. I think the 4x8x16 with no holes for like $0.97 was the most useful for your purposes. A more specialized provider can sell you longer stuff, too; "concrete blocks" in the yellow pages. (If you strike out, there's one up here that I know has long solid pieces; to my way of thinking, you may as well just get big slabs instead of putting together lots of little ones.) I was at HD because I was considering replacing our disintegrating brick steps with slabs of somethingorother, but I ended up just replacing the bricks instead. (Well, starting to replace bricks. I finished the top, filled in the holes in the middle, and laid three bricks before I ran out of mortar.) The really annoying thing is that, totally spontaneously, some bricks on the bottom decided to give out sometime within the last few days, too. --andrew My folks say they got "split-face concrete block" at the ServiceStar hardware store in CT, which is 8x8x16 just like regular concrete block, with a rough face, at $1.80 each, with little plastic spacers that make them fit together with an offset, at .60 cents each. They also mortared on 8-inch patio blocks to make a top for the wall. They say it's quite solid that way. Blocks not at Home Depot. If you can't find them try calling 203-374-6133 in Trumbull, CT if you want to ask who makes them. --LizM ea, verily. Rather more expensive than simple concrete block, but it looks and performs much better. I don't know if Home Depot has it... a masonry supplier would (out by Worcester there's Camosse Masonry Supply which I use for these things... don't know what there is in where you are...) --Jim Paradis Cinder blocks, like most concrete-stuff, is quite fragile when under tension. It cracks very easily, which is why they have to use rebar. So if you're using them to support loads (like your car), ALWAYS put the load along a solid path, i.e. set it with the holes up/down, not sideways. Blocks crush as the hole collapses. Oilpan imprint on chest. -dca Another vote for this stuff. We have used it for 3.5' retaining walls, and it doesnt move over a bunch of years in a bad (southern Quebec) climate. It is NOT the block and spacer stuff Liz mentioned - it looks very awkward - a sort of angled-off, flattened peanut shape is the best description I can come up with - but of course thats why it locks together well. May be overkill for your app, but loose square block is underkill- will fall over or become intolerably unneat in a year or two w/o mortering or running something down the holes. -h |
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