Build Your Own Raised Beds

comments (26) February 24th, 2009

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You can build this 4x8 raised bed with basic carpentry skills (see the instructions on page two, at the end of this article).
Each raised bed takes about half an hour to build, once you have your materials together.
You can reach the center of this 4-ft.-wide bed from either side; the pathways, which are 3 ft. wide, accommodate a wheelbarrow.
You can build this 4x8 raised bed with basic carpentry skills (see the instructions on page two, at the end of this article).Click To Enlarge

You can build this 4x8 raised bed with basic carpentry skills (see the instructions on page two, at the end of this article).

Photo: Rosalind Wanke

Raised beds solved many of the garden problems that faced me 20 years ago in our new southern California home. Among the challenges were terrible soil, a concrete-paved yard, arid growing conditions, small children, and a big, exuberant puppy. I found the raised bed solution to be a great success, and only now am I having that first set replaced with new ones.

A raised bed brimming with plants
But let me tell you the story of my garden. When we first saw our house-to-be and read the realtor’s description, five words eclipsed all others: Perfect Back Yard for Pool. To a gardener (me), those words meant a warm southern exposure and a sizable empty space in which to plant a vegetable garden.

The sizable sunny space turned out to be about 2,000 sq. ft. of concrete pavement, minus a 3-ft. planted perimeter. True, it was large enough for a decent-size garden. But also true was that what little soil existed was heavily compacted and lacked organic content.

Once before, we had been faced with difficult growing conditions. On a granite ledge with no soil in New Hampshire, my husband had built a raised bed where I grew a small salad garden. Why not design a system of raised beds that would allow me to grow vegetables year-round?

Getting more for less from a raised bed

In addition to the concrete and poor soil, there were a number of reasons raised beds seemed the perfect way to garden. First, my husband, Frank, was an accomplished carpenter and could build the boxes. Second, we could leave the concrete in place and simply break up the portions under the boxes to provide drainage.

Black gold
  Dirt poor, the original subsoil (left) became black gold (right) by amending it with chicken manure, compost, and topsoil.
Soil quality was a third reason for raised beds. We were able to create soil by using compost from our previous house (we had moved the entire pile). We supplemented the compost with some topsoil and chicken manure, and had a great, easily worked growing medium.

Because we live in a Mediterranean-type climate with less than 10 in. of rainfall per year and almost none between April and November, we knew we would have to irrigate. Raised beds allowed us to set up an irrigation system that included a hose bib in each box. This would allow us to water each bed independently.

It didn’t take long for us to see that our raised beds had several unanticipated advantages. Our golden retriever puppy loved to race around the beds but rarely jumped into them. Our children, Josh and Jessa, could easily ride their Big Wheels around the obstacle course we had unwittingly developed for them. And neither these activities nor my gardening compacted the soil because no one ever walked on it. It remained fluffy and well aerated, allowing plant roots to grow freely.

Deciding on the design
Redwood raised bed
  Redwood is the material of choice for West Coast gardens, and once you have your materials together, the beds take only about half an hour to build.
  Redwood raised bed
  The 4-ft. width of the raised beds allows the author to reach the center from either side. Paths 3 ft. wide accommodate a wheelbarrow.
I wanted eight raised beds, and I wanted them made of wood. Construction-grade redwood, which contains knots and some imperfections, seemed like a logical choice, since we knew it would last many years and would cost less than $100 to build the eight beds. But that was 20 years ago. For a recent replacement, the wood and nails for one box alone cost about $90. [Editor's note: This article was written in 1997.]

The design of the beds was derived from several practical considerations. The dimensions, 4 ft. by 8 ft., were based on the fact that lumber was available in 8-ft. lengths, so it would require a minimum of cutting and no waste. I could comfortably reach only 24 in. into the beds, so a width of 4 ft. would allow access from both sides to the middle.

I also measured several of our chairs and found they all had a seat height of 16 in. to 19 in. Since we had decided to use 2x6 redwood, we could stack the boards three high and end up with a finished height of 16-1⁄2 in. (the actual width of a 2x6 is 5-1⁄2 in.). This made the edge of the box a comfortable height on which to perch and gave more than enough root run for the plants.

The boards were nailed to 4x4 corner posts that extend nearly 8 in. higher than the sides. I use bird netting during seed germination and clear plastic to warm pepper and melon seedlings. I drape these covers over the posts. The paths between the beds are 3 ft. wide to accommodate a wheelbarrow, which I use to transfer compost from its bin to the boxes.

Nail the boards to the posts   Assemble the bed
Two nails per board secure the boards to the post. The bottom board should be flush with the bottom of the post; the top of the post extends about 7-1/2 in. above the top board.   Stand the long boards with posts on the ground, parallel to each other and 4 ft. apart. comoplete the bed by nailing the short boards to the posts.

After you try it, show it off to other members in the
gardener's gallery.
Post your photos

posted in: raised beds, structures

Comments (26)

timonrooster writes: great ideas.. thank you for sharing
Posted: 3:42 am on August 20th
charisbaker writes: it's really useful information...
Posted: 2:04 am on August 20th
lyunmoss writes: thank you for share your ideas
Posted: 5:55 am on July 26th
DonnaCox writes: thnx for sharing your ideas, i was really need this.
Posted: 2:16 am on July 26th
aboveground36 writes: when i built my above ground gardens (2) i put 4x4 posts on each corner and 1 on each side and they were screwed in from the inside of the box. they are 16 inches high off the ground. the bottom of beds were covered with cedar wood, same as the beds were made of and holes were drilled in the wood on bottom of beds for drainage. also, i filled the bottom of the beds with plastic bottles with the lids on. if using beer cans, lay them flat along side each other. this helps so that you do not have to "fill" the beds with so much soil.

i put bottles down, then a layer of leaves and then 2 bags of garden soil, 2 bags of cow manure and another 2 bags of garden soil. this was enough to fill a bed 4 feet long by 2 feet and 2 feet deep. the soil will need to be stirred up and added to each season before planting again.

after the growing season, i put a layer of leaves on the soil and mix it up to help fertilize the soil over the winter months. i live in wisconsin and the snow covering the leaves helps to keep them in and also keeps moisture so the leaves will deteriorate. save your water bottles and lids or any plastic jar with a lid. have any question? i'll try and answer them for you.
Posted: 1:05 am on April 8th
wagnea writes: My husband and I have made many raised beds. We attach our side boards with screws, not nails. We also put L brackets on the outside of the corners. Ours are made of redwood, available in California. The advantage to a raised bed for us is, we can line the bottom with gopher wire. No missing veggies from underground creatures. We also have a real problem with sparrows in the late winter and spring. With the raised beds it is easy to attach some 2x2 to the sides and drape some bird netting over the bed.

Posted: 11:17 pm on January 28th
Lizzieplants writes: We built 10 raised beds with pressure treated deck boards lined with heavy black plastic. It took a lot of compost and soil to fill them. They are about 17 inches high. I would like to bring the beds up to standing height like those you find at assisted living facilities. We are getting older and the bending is hard on our backs.

Any thought on how to do this without spending a fortune on soil? Is there something we could fill the bottom in with?
Posted: 9:38 am on January 27th
silaswren writes: Nice work.. Impressive
Posted: 12:26 am on October 10th
NorthwestNative writes: One solution to rotting boards is to line the planter box with garden plastic. I folded it over a piece of lathe and then secured the lathe to the sides of the planter box with staples. It keeps the beds from rotting for a LONG time (more than 20 years in my case) and helps keep the soil from drying out.

This approach alleviates any worries about the type of wood you use and makes it possible to use whatever is available because it does not come in contact with the soil.
Posted: 2:09 pm on May 27th
Downeast_Pete writes: Ruth writes: Masik, this is an old article, so we can't ask the author about exact soil quantity, but we can do the math. The bed shown in the drawing is 4x8 and roughly 1-1/2 ft. deep, so filling it would require 48 cubic feet of soil (5-1/3 cubic yards). Hope this helps.

Ummm, I'm just a dumb Maine hick but as far as I know there is 27 cu ft in a cubic yard. Not sure how you get over 5 cu yds from 48 cu ft?

You are also calling the bed 4' x 8' x 1 1/2 ft deep but it is not that deep. The author uses three 2 x 6 section for the sides, since these are actually nominal 5 1/2" the bed is actually 15 1/2" deep. Subtract the 4" freeboard
The author suggests and you have actual depth of 11 1/2". So, it would take between 1.08 & 1.18 cu yds of material to fill a raised bed using the Authors dimensions/plans.
Posted: 9:28 am on May 20th
Stella84 writes: Juniper, in my opinion, is the best choice for raised garden beds. Juniper is long-lasting, beautiful, and chemical-free lumber that is being harvested in in the Northwest. The selective harvest supports local family-run mills committed to restoring Northwest ecosystems. Juniper lasts much longer than cedar or redwood, up to 50 years or more in ground contact applications. Juniper is especially suited for this purpose because of its naturally high oil content that is decay and rot resistant. It is chemical free! Do you really want to use chemically treated lumber where you grow your food? I built mine out of Juniper and love that fact that they will last and I am helping the environment. Google Restoration Juniper to learn more about it and where it can be purchased.
Posted: 9:52 am on July 3rd
tims1chap writes: I just built the 4X8 described above. I purchased pressure treated lumber, 50 bags of good top soil, 4 bags of manure, 2 bags of Miracle Grow Garden soil at Lowes for $154.67. Not too bad and it only took a couple of hours to do all of it.
I think I will have to add about 6 more bags once the dirt settles some.
Posted: 3:57 pm on March 30th
Rayngardener writes: The design looks great but I am extremely disappointed that a gardener is willing to use non-renewable wood... Redwood. I assume that home gardeners are advocates for the environment. Please do not support the cutting of redwood trees.
Posted: 5:16 pm on January 24th
MaddieFH writes: I made 3 raised beds two years ago. You can buy the prefab ones, but dollar for dollar, making your own gives you a better depth than the prefab. I made mine w/ cedar wood. The boxes ended up costing about $42 each for 11" deep, 8x4 waste. that is going to a Loewes and get the untreated decking boards. If you have a sawmill nearby, perhaps you can get some rough cut lumber. I used good decking screws and with a wood that doesn't rot, I anticipate many years of use. The cedar does discourage insects, but once I put compost in with a supply of earthworms, they seem happy to oblige me with healthy soil. The cedar turns grey with age.

Posted: 12:38 pm on January 1st
Rapscallion2 writes: This is the most fantastic article that I have come across on the topic of raised beds; and I have been doing extensive research as one that is good at so doing :)

Most do not address challenges and the minutia that are usually lessons hard learned.

Unfortunately I found this article just a little bit too late in my project to address some future challenges - that have been addressed so well within this article; there are several things I would have done differently 3 days ago ;)

My project involves the design & installation of two 4X12 raised beds over hard clay / builders backfill. The client specified 12" deep beds, but I suggested at least 18" (given what they wanted to plant) given the nature of their native soil.

I found a really cool 4'X4'X1" X9" high finger joint cedar 'kit' complete with 4X4 trellis (Suncaster - on sale for $30 (from $79). Having explored various other construction material options, from both a labour & cost perspective (with serious emphasis on bed depth), I chose to buy 8 of these kits to create two 4X12X1" (thick) X 18" deep beds. None of the 2X, or commercial 1X or 5/4X could compete with the price to create a similarly deep bed.

I had to install cross bracing to prevent the 12' long sides from mis-behaving at the 4' joint points, vertical posts to tie the 2 levels together and lend greater stability to the 1" thick walled beds, and install narrow strips of land-scape fabric to prevent the soil from seeping out between the lower and upper courses and at the finger joints (my aluminum 1/8" thick X 1" wide X bed width cross bracing increased the inter-level gappage to 1/8" at the aluminum pin down points holding the finger jointed 4X4X9" boards + brace together.

I would have handled many things differently had I come across your article 3 days ago ;)

Lucky for me, having found your article before the end of the project, I will consider installing landscape fabric differently for the perimeter paths, exterior seating vs. capping the bed tops with seating boards (given that they will interfere with turning the beds - never thought of that), and flexible / easily removable options for irrigation system.

You guys are great - thanks for sharing your hard found knowledge.
Posted: 8:49 pm on October 14th
SweeneyTodd writes: Masik, and any else who are interested:

The raised beds above hold 1.18 yards (32 cubic feet) of dirt if you leave a 3 inch gap at the top of the boards.

How to calculate your dirt needs:

For this box:
Depth x Length x Width
1 ft x 8 ft x 4 ft = 32

Conversion to Yards = Cubic feet / 27 (1.185 as shown above)

For slightly more comlicated depths or sizes, the pattern still works, but everything needs to be converted to the decimal version of measurement:

18" of soil = (18/12)feet = 1.33 feet deep
5'7" long = 67" = (67/12)feet = 5.58 feet long
2'4" wide = 28" = (28/12)feet = 2.33 feet wide

1.33 x 5.58 x 2.33 = 17.29 cubic feet
17.29 / 27 = 0.64 cubic yards

Hope this helps.

And remember, most businesses sell soil or compost by the half yard, so in both of the cases above, you might want to buy topsoil and then supplement it with a few bags of peat, compost, or manure to add nutrients.

Posted: 2:32 pm on April 30th
justachick writes: Descolian writes: "I then replaced all the sleepers with low brick walls on a concrete foundation. The area now looks much tidier and is easier to maintain. In my old age I can also garden sitting down on the brick. (NSW, Australia)"

Id sure love to see how you used the bricks as Ive just been offered a truckload of used bricks if I want them.
Posted: 6:23 pm on March 1st
Descolian writes: I used old railway sleepers for the construction of our garden beds, but after five years, some of the old hardwood rotted and allowed couch and Kikuyu grass to penetrate. I then replaced all the sleepers with low brick walls on a concrete foundation. The area now looks much tidier and is easier to maintain. In my old age I can also garden sitting down on the brick. (NSW, Australia)
Posted: 11:04 pm on February 29th
oracal writes: I have four raised beds I built using redwood about 10 years ago. I'm also in Southern California. My redwood beds are pretty rotten already--they still hold the dirt, but are going to need replacing soon. Regardless of what anyone tells me, I will never use any type of pressure treated wood for my garden beds. The next time I replace my beds, I will probably use a composite decking material like Trex. I know its expensive, but it will be the last time I have to replace them.
Posted: 1:15 pm on February 29th
DirtyJohn writes: I've built 6 4x8 redwood raised beds, 20" tall with bench seat to be easy on knees and back. Well built (and not cheap), so I want them to last. They're sitting on a well-draining brick patio. I'm considering lining the interior sides with 4 mil plastic to keep moisture, dirt, and bugs from direct contact. Your thoughts?
Posted: 10:34 am on September 3rd
LindaChisari writes: Hello! I am the author of the Raised Bed article (14 years ago!). There are 27 cubic feet in a cubic yard, so it takes just under 2 cu. yds. to fill a bed. You'll want to keep the soil level about 4" below the top to allow room for whatever irrigation system you use and to prevent soil from spilling over the top when you dig!
Posted: 2:48 pm on February 14th
Ruth writes: Masik, this is an old article, so we can't ask the author about exact soil quantity, but we can do the math. The bed shown in the drawing is 4x8 and roughly 1-1/2 ft. deep, so filling it would require 48 cubic feet of soil (5-1/3 cubic yards). Hope this helps.
Posted: 8:45 am on January 19th
Masik writes: What a GREAT helpful review if a raised bed! Would you care to share how much soil actually go to 1 r.b.?
Thank you!
Posted: 9:41 pm on January 18th
genosgarden writes: Great pictures and instructions. I'm getting my materials listed and prices and hope to spend Mother's Day making my first bed! Yea! I'll send you pictures. Jeannie
Posted: 4:53 am on May 5th
pcworth writes: Just wanted to add that people should read this Fine Gardening Article:
Posted: 9:49 am on April 27th
pcworth writes: I definitely agree that people should not use CCA preserved woods, but the new environmentally "friendly" arsenic and chromium free preservatives used in pressure treated lumber make pressure treated lumber a good choice now.

If you read the research on Ever Guard and similar micronized copper products, it seems that although some preservative leaches out over a long period it is sequestered by the soils and not taken in to plants.

It is probably no worse than water from some municipal supplies, or copper plumbing.

Posted: 9:23 am on April 27th
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