Instructables
I have been using raised beds for several years now. I converted an existing patch of grass into four, 4ft x 12ft raised beds for a total garden area of 192 sq. ft. This could, conceivably, produce enough food throughout the year to make a serious dent in the food budget. And, of course, all the advantages of raised-bed gardening are realized. However, I have had to replace several end boards due to rotting out at the corners. In order to prevent this from happening, I came up with a way to use concrete as a corner brace, and thereby stop the rotting and make a more permanent installation. Starting in step 7, I show how to replace an end board that has rotted out at the corners.
 
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Step 1: Materials Needed

The usual concrete tools, materials and supplies. For my mix, I used a ready mix concrete so that I would be sure to have a uniform, strong concrete. For the bed itself, I choose to use 2x dimensional lumber. At least one bed is made with 2x12's, one with 2x10s, and so on. A 2x6 is certainly big enough, so it is a matter of personal preference. In this instructable, the lumber is 2x8's.

Step 2: Making The Form

The form is made using 1/4in. plywood, and 1x6 lumber cut to the correct sizes. See pictures for specifics. A key part of making these braces is the addition of a piece of wire mesh into the mold. I chose to use some rabbit wire for my reinforcement. It is easily cut with wire cutters, and shaped to fit within the mold between the bolt holders....these have been made out of regular PVC pipe, which is the 1//2 inch size. The form is assembled using drywall screws. Before assembly, it is a good idea to apply a coat of oil to the wood pieces to act as a release agent for the concrete. I just used some vegetable oils, but any oil will do.
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gaelicwinter made it!6 months ago

I placed the concrete corners on the outside of the wood to match the style I'm using in the rest of the yard. Galvanized carriage bolts to hold it together. Poly fibres in the concrete means I could make the corners about 1.5" thick. The vertical frames for the clematis are cedar and stainless steel. Solid stain on all wood.

image.jpg
Creativeman (author)  gaelicwinter6 months ago

Good job! That's a very attractive arrangement for your yard!

ntense991 year ago
Nice pavers! I used the same pavers / form for my entire home!
https://www.facebook.com/media/set/?set=a.522403854473323.1073741837.508872869159755&type=1&l=8a292ab03c
Creativeman (author)  ntense991 year ago
That is one awesome, serious project! 5 stars for sure, you should enter it in all the contests you can find...a sure winner. Thanks for sharing, and did you do an instructable?
I love how you used the pavers between the raised beds; gives me some ideas - i was kind of in the market to build a veg garden and want it to look nice; yours is awesome!
thanks man! negative, i did not make it into an instructable! maybe one day i will :)
MuffyCase2 years ago
I love your set up and the walkways in between and around the beds. I have to ask (because I believe this is the design I have planned for my garden)..but are the walkways made by using the Quikrete walkway mold? I had a vision and love seeing what it would look like once finished. Awesome job!
Creativeman (author)  MuffyCase2 years ago
Thanks for your comments muffycase! Yes, I used the quckcrete mold...they are alot cheaper now than when I bought it...
That's the same one I used:
https://www.facebook.com/media/set/?set=a.522403854473323.1073741837.508872869159755&type=1&l=8a292ab03c
ariviera1 year ago
I really enjoy the open discussion and trading of ideas this instructable has spurred. The concrete corners are an excellent idea, but i wonder if it would also be possible to form reinforced concrete walls as well, using rebar or mesh. The walls themselves would use a different mold, but once you build it you are unlimited as to the number you can produce. Just a thought to bypass the issue of rotted wood and potential leaching of chemicals. Again, great instructable and I really like the discussion going on here.
we don't have rabbits, or gophers. we do have possums, skunks, and I have 2 cats. I am more worried about the cats thinking it is the best litter box ever.
I love your design. I am pretty sure Hubby will dig it. Since he is the "builder" he needs to like it. thanks,
About your cats, if it gets to be a real problem, you may consider getting this device that emits a very hi-frequency sound (humans, not even birds can hear it), but only when the animal gets within range. The cat will come to associate the unpleasant noise with being in the garden or wherever he happens to be that he shouldn't be. Here's the link: http://www.safepetproducts.com/cat-stop-cat-repellent-1-cat-repellent-on-the-market.html?utm_source=msn&utm_medium=cpc&utm_term=contech%20catstop&utm_content=m350715038&utm_campaign=msn-campaign-catstop#.UZIrGKDn91s. You can also try planting Rue, Bergamont, Coleus Caninea (aka Scardy Cat plant), lavender, geranium, rosemary & garlic cloves, or plant prickly plants in and around your garden... all of these are known to deter a feline's interest in an area to a certain extent. And/or plant a cat garden with cat nip, grasses and let him know this is his place.
sapplegate1 year ago
What is the cost overall for one 4X12 bed?
Is 4X12 a functional size?
Do you put any chicken wire across the bottom to limit gophers?
Can you add an upward post to the corners for a fencing around the garden? (to keep the dogs and cats out of the garden.)
Thank you so much. Sara
Creativeman (author)  sapplegate1 year ago
Sara: I originally spent $200 for four beds. That could vary widely depending on materials chosen, and the extent you want to go to. This size was perfect for my spot, and the dimensions lend themselves very well to square foot gardening. I didn't line mine for the gophers, but it would have been a good idea. Yes, they can be fenced as you suggest...I haven't had to do that, although the racoons do considerable damage looking for grubs and such....good luck.
IG-885 years ago
How come you didn't go with that green treated lumber or perhaps cedar? Cost?
The green in treated lumber is either amine copper quat (ACQ) or copper azone (CA), both of which are poisons. Having them mix with ground soil and water may leech into the plants -- not a healthy idea. While expensive, hardwoods like redwoods last much longer. A note to Creativeman: Bolted ribs (stakes bolted to the sides of the planks) that are twice the size of the planks (half on the plank, other half buried) will relieve much of the stresses put on the corners and will increase the rigidity of the overall form.
 This isn't entirely true...

OLD CCA lumber has been banned for consumer use since 2003/2004 ... Arsenic was the main component there that was causing problems... Pressure treated wood now still has copper in it... but copper interacts with other metals in the ground not really plants... Some people even plant copper wiring to ward out snails and slugs as pests in their gardens!

I've used pressure treated wood in my raised vegetable boxes and its been great!
You realize of course you are probably going to die a slow an agonizing death now. All those harmful copper toxins you have been eating all these years are adding up and pretty soon BOOM!, your insides are going to explode!

Really, I think some people take this organic thing a bit far....
Copper wire is pure, metallic copper in solid form that will only leach in tiny, tiny amounts-NOT so in the pressure treated wood. The copper in PT wood had to be put into a very soluble form to permeate the structure of the wood and it's the SOLUBLE metals/toxins that you need to worry about.

Remember, most of your plumbing (other than the waste/discharge lines) are made of pure metallic copper and has been for generations and hasn't caused problems...yet...
irontank5 years ago
lol, yea, I was trying to figure out why you went to all the trouble to make the concrete corners. Why have corners at all, just nail the wood together with galvanized nails and lay some plastic in there and be done with it. But the concrete is super cool, you could use PVC. Just slit a 4" or so pvc pipe down the center heat it up and lay it on a flat surface. You'd have a flat plastic piece that will never rot and probably cheaper then a bunch of concrete.
The problem is that PVC releases toxic chemicals such as dioxin when heated and even after it's cooled and hardened again it is much more prone to leaching the chemicals into the soil and your edibles. At least concrete mostly just produces CO2 when made-and in many cases it somewhat safely binds/incorporates "fly ash" (a by-product of burning coal) that would otherwise be a pollutant.

Side note: cement production *is* one of the largest contributors to the rise of atmospheric CO2 but when used carefully in small amounts and for durable uses like in this project, it can make up for it.
Creativeman (author)  irontank5 years ago
Good thoughts, thanks. Cman
cojonc5 years ago
Loads of those built up gardens around. It's a good idea and I think more and more people will do it. Gives better control of the soil. If one were to make all the gardens 4x4 foot, the soil in each could be conditioned to the plants in that section. As example tomatoes. They typically do poorly in soils with a PH under 6.

I built one next to the house for plants. It was a two-tier with a shelf above for plants that hang down over the pots. Really looks great! I handled the rot problem (I hope) by pouring a concrete footer under the boards to keep them off the soil. I like to 'mound' the concrete to cause any water to run off. I just use a form of level 2x4's staked in place where the planter was designed to be. Then I dug holes 18" deep for 2x4 posts in the corners and every 4 feet. These I cut from a single 4x4 treated with .060 ppcf ACQ for buried conditions.These posts are concreted into place as this bed is to be permanant. Then I paint on a sealer (stain in this case) to preserve the wood from the effects of weathering--pressure treating stops the rot, sealers stop the weathering... two different things. Two thicknesses of heavy plastic sheet is used for covering the inside of the 2x8 boards that retain the dirt. The sheet is folded over about an inch wide three times, then stapled on top, and the staples are covered with 3M 5200 sealant to stop any water penetration. Then it's draped down the board, and into the planter about a foot.

Now I screw down a sealed but not treated 2x4 on the top to resist bending pressure against the 2X8's, make the top attractive, cover the plastic, protecting it and shading it from ultraviolet radiation. I cut the 2x4's drill them for the galvanized screws, put in the screws and add more 3M 5200 sealant top and bottom to keep water from entering, then screw down the boards. Sometimes I come up from below ground with a PVC twin pipe watering system that can be put on an inexpensive timer, but I didn't in this case as it contains basically shrubs and flowering plants I won't eat. Then I fill it with clean soil, mounding it about 4-6 inches in the center, and bringing it to within one inch of the bottom of the 2X4 topper. Next I cover it with the sturdiest black plastic sheet I can find, tucking in the edges all around about 6". This contains the mound I made in the center, heats the soil for better growth, and inhibits weed growth. Finally I cover it with mulch or even another inch or so if soil. This brings it to the lower edge of the 2x4 topper, covering and hiding all the plastic.

I wrote this quickly and in brief, so pardon me if I missed anything, but that should keep the 2x8's in good shape up to a theoretical 20 years. If you want a belt and suspenders approach, additionally paint the wood with a propylene glycol (antifreeze) borate solution to extend the rot protection. (formula online here) The 2x4 topper will rot, but it's easily replaced and inexpensive. To plant, I cut a small 'X' in the plastic and put in my plants.

Here in East Texas, where the soil can be used without additives to manufacture very high quality bricks (red or yellow clay), this raised bed gardening is extremely popular. Hmm, perhaps, necessary is a bit more appropriate term. I was building an area in the back to have a concrete floor, and made a flattened area, dished to later get a central drain, but nothing else had been done. It rained and the water, five inches deep and ten feet across, remained for more than two months. Makes for an easy swimming pool, eh?

I am a former sailor and very familiar with the problems of wood rot, so I prefer the more involved process. I'm use to it, love the detailed, scientific approach, and I seriously doubt I could actually put down wood and expect rot when it is reasonably easy and inexpensive to get all my web-footed swimming birds of the family Anatidae in a row and maybe, just maybe, not have to ever do it a second time. Plus it looks bloody great stained, mate!

I sincerely enjoyed your instructable, and I thought your concrete corner post idea was noteworthy. I am going to run it through the processes a bit more, but it's an interesting idea. Might use it myself. Can't rot that stuff, huh?

Thanks all around for the effort you put in and the quality of your work. Much appreciated!

Oh, one more thing. Those who feel that the treated wood would be dangerous around gardens, or the leaching of concrete too alkaline, might consider the amount of chemical likely to permeate the soil to any significant PPM over distance. I have not checked specifically, but given some nominal considerations, I find it unlikely that any effective molecular transport mechanism exists in garden soil. If the contaminates make it an inch or two from the site, in any appreciable/damaging PPM I would be surprised. Are there recorded instances of death or illness (esp with ACQ) directly attributable to raised bed gardens or similar constructions? Additionally, the 2X8's are only ACQ (20 ppcf) as they are not intended for ground contact. I have done this before and eaten the fruit, roots, etc. I'm almost 70 and I still feel like I could successfully take on a full grown supremely conditioned male baeolophus-- even during mating season when he is fully charged with strength building hormones. . . and prevail.
Baeolophus. Typo? Or did you really mean a Titmouse? Just curious.
Yes, a titmouse. Some can be quite formidable--especially the big ones.
zurkog cojonc5 years ago
Here's a baeolophus issuing a war shriek, just prior to attack. Note the razor sharp talons. Scary stuff.

http://k43.pbase.com/g6/15/373415/2/69828942.DiiTyh8t.jpg

Back on topic, this is a very useful instructable; thanks! I'm pretty handy constructing forms out of cement, and it never occurred to me to do something like this. I very much want to start a raised bed garden with drip irrigation. The house I'm in right now has almost no yard in full sun; the next house I purchase will definitely have room and proper sunlight for raised beds.

I've seen raised beds where they attached tar roofing shingles to the inside of the 2x10's to help keep them dry. Any opinions on that tactic?
cojonc zurkog3 years ago
I could not help wondering, did you ever do a raised bed garden? if so, would you share your results? By the way, full sun is not always a necessity to having exceptional plant growth. We are in the middle of a forest of 50 to 70 foot loblolly pines and get exceptional growth in all our plants. Oh heck, I'll just give you and everyone the details. As a former columnist, I learned to enjoy writing.

My garden is completed except for a revision on the topping boards which suffered from inconsistent corner height as the boards moved from sitting on them and the corners twisted uncontrollably. I am replacing the topping 2x4's and adding either a wide half-lap at the corners or routing a space under the corner joint for a 1" support that holds the corners together more securely. That should allow sitting and standing without the twisting problems.

The garden has been growing for a year now. I love the raised bed appearance, and especially the old bricks with the stained 2x8's making the walls of the garden. The 2x4's I put on top to make the edge wider have proved to be absolutely worth the extra effort and cost--except for the correctable problems mentioned above. The plants we have grown are the topping glory and because of a scientific approach, are mind boggling in size and scope.

Because of the soil I "manufactured: by collecting my food garbage and biodegradable wastes for "fermenting" in an old bathtub on my side yard I have excellent mulch, which I mixed with some imported black soil. (We have red and yellow clay as the predominant soil in east Texas) I also have drip watering on a timer and I administer correct does of 10-10-20 or similar plant foods, and additional chemicals plants benefit from. Epsom salts as an example. Epsom salts is actually magnesium sulfate, and activates many enzymes used in photosynthesis, plant respiration, and protein synthesis. It contains chlorophyll, which is responsible for photosynthesis.

Most home gardeners don't use a scientific approach and do not realize the usefulness of researching topics and augmenting soils, so they are struck dumb when they see my garden.

My home is in the middle of a pine forest thick with 50 70 foot loblolly pines. Only my tiny quarter acre plot was cleared and it still had five large trees. The garden is on the North- East side of the house and gets very little direct sun--less than three hours. Regardless, the elephant ears (Colocasia esculenta) my wife planted and tended did amazingly well. The usual size for this plant in the states is about 2-3 feet tall with a leaf about a foot across. What we got was true typical of tropical growth for this species with leaves to three and a half feet in length and more than two feet wide on a plant over nine feet in height.

The garden is raised almost 18 inches and the elephant ears (a dozen plants in a space eight feet long) dominate by growing in tropical profusion. Below them are plants of all sorts including shrubs, flowers, grasses, ground cover, creeping types, and so on of varying colors. There is a path in front of the garden and you have to work your way through them, pushing aside umbrella sized leaves coming from stalks the size of a mans arm.

We really love that area, and as our age allows, we will continue this plating and gardening approach until the back lawn is surrounded with a jungle of annual, deciduous and evergreen plants designed to provide a spectacular look year round.

If any of you are thinking of doing a raised bed garden, I sincerely recommend it and also careful use of good soil and plant foods. The results will please you more than you might expect.
zurkog cojonc3 years ago
As a matter of fact, I did. I finally just trusted my gut instincts and built it out of eight foot long 2x6's, stacked two high for a total height of almost a foot. I cut the ends in half, so the beds are 4 foot by 8 foot, and I have two beds. I used metal flashing to secure them all (I believe its intended use is to keep your roof on in the event of a hurricane strike), used liquid nail in between the top and bottom boards, and even rented a rototiller for a day to dig down and loosen up 6-8 inches of the soil underneath the beds. Here's one of the few photos I took, right after we put some plants in them: http://i.imgur.com/7T1oh.jpg My daughter is holding her lima bean up to the sun to get more light.

We planted eggplants, pole beans, and cucumbers, all of which did fantastically. The cucumbers produced so much it was almost humorous. with 4 plants, we were harvesting more than 2 a day, on average during the peak. We also planted yellow squash and butter nut squash, neither of which did very well, and a few pepper plants that hardly produced anything at all. I got -one- jalapeno pepper the size of my pinky, and a single bell pepper the size of a golf ball.

What the photo doesn't show, and what was a surprising success was the EarthTainers: http://www.earthtainer.org/ I built 5 of them, and planted two tomato plants in each, and after I moved them around the back yard in search of sunlight (with the help of a dolly - those things are HEAVY when fully laden), the plants grew like weeds, and I was harvesting tomatoes until December 4th, when the first hard freeze killed them off. I highly recommend checking out the free plans he's got on his site. It only took a couple weekends (and a few trips to the hardware store) to get them built.

I used the soil mix in the earthtainer guide (potting mix / pearlite / bark fines) to fill the raised beds, and was very happy with it.

Right now, the beds are empty, although I'm about to toss the spent soil from the earthtainers into the beds, along with some leaves, and I'll throw some annual rye grass seed on top to act as a green manure.

I'm just getting started with this gardening stuff, so I haven't started composting yet (but plan to this season), nor have I set up drip irrigation (which I definitely plan to do this year). Scientific approaches always appeal to me, and I'll have to start tweaking added chemicals and plant foods too. I just haven't figured out the best vegetables/fruits to plant yet; definitely cucumbers/eggplants/pole beans, but I'll have to try some different ones this year, too.

Thanks for the update, I'm sure I'll have more questions in a few months!
cojonc zurkog5 years ago
I am using the natural clay of the area to form the cement channels below the 2x8's. I made an adjustable digging tool that glides along the 2x8 as it carves a trench below for the concrete. This saves on the forms, places the concrete at ground level, and gives room for the bricks that will be set in mortar on top of the concrete footer. This keeps my wood forms off the soil and provides drainage while looking purty slick too.

On the shingles. Sorry, they won't help unless they are sealed both top and bottom and side to side. Water can and will enter anywhere they are open to the environment--through the cracks between where they join. I'm using two layers of 4 mil plastic to accomplish the same thing and sealing the overlaps with 3M's 5200 (read the specs first-here) Regardless, the plastic is in contact with the wood and will create an area where there is no air circulation to remove moisture. This creates the moist, warm, dark environment the many fungi responsible for wood rot can flourish in. Anytime the moisture climbs above 20% (and includes the conditions I described above), these fungi will generally flourish. I offered a home brew wood rot preventative solution earlier and will again (here) . As a long time sailor, I have used this and know it is effective.

I plan drip irrigation as well, but will be placing 55 gallon barrels to catch rain from the roof (via the gutters) during the winter to use for summer irrigation. If I can place them at 6 feet, I will have the head to go without a pump. I have not looked into timers yet but will.
Michael_oz4 years ago
Great idea. You could also use some 45 degree molding (or maybe concave round) on the edges of the mold to get rid of the sharp 90 degree ends, I imagine stepping on or kicking the concreet in bare feet would hurt.
dittyjunk4 years ago
Super nice idea I love it.  I will do mine in retangle cube block.  Easier to manage and easier to build the form.   Thanks for the idea.
Jason_G4 years ago
Thanks for sharing! Wasn't there an Instructable for that stepping stone pattern that you have around your raised bed?  I can't seem to find it- can someone help me out?  Thank you. -Jason
Creativeman (author)  Jason_G4 years ago
dougbyte5 years ago
Great Instructable A swab of diesel fuel on the forms will make them separate from the concrete easier.
Or a layer or two of newspaper. I discourage the use of petroleum products anywhere near my garden or groundwater no matter how much. Also, newspaper makes a suitable weed block, compared to that roll of black material stuff.
Vegetable oil isn't a petro product though, so you should be good.  You can also use animal fat or oil left over from cooking meat, and that stuff will actually feed your garden quite nicely.
I was referring to Diesel fuel. dougbyte, not Paladin. look at the dates.
 Or used cooking oil. It can been oil - just a veggie oil. 
Linda McCue4 years ago
I've never tried this although I have a book or two with the beds in them. Your instructable makes it seem less intimidating. Thanks. I had a thought as I followed along. There are bookshelf ends for putting together bookshelves easily. They're cheap and reusable. Many people throw out their bookcases and leave them in place or sell them at garage sales. This would make your initial construction easier. Then if you covered the joint with concrete or a protective solvent, the ends would be less likely to rust and break as time went by. Again, great job.
Creativeman (author)  Linda McCue4 years ago
Thanks for your input Linda, may try that as time allows.  You know, so many things, so little time! Cman
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