Build Your Own Raised Beds

comments (16) February 24th, 2009

Pin It

thumbs up 255 users recommend

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

1 | 2 All

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.
   




Accessorizing your raised beds
Beds can be custom designed and accessorized. For some clients, I have designed beds that have a 6-in. board or “cap” around the edge to make sitting more comfortable. (This does make it just a bit more difficult to turn the soil, though.) Others have corner posts extended up to 8 ft. to allow attachment of trellises for beans, cucumbers, and other climbers. In gopher-prone areas, beds have hardware cloth tacked across the bottom.

For some beds, I have devised a system of hoops, using PVC irrigation pipe, over which to drape bird netting or row cover to keep cabbage loopers out. Brick or stone raised beds can be used to retain small slopes. Other beds divide gardens into “rooms,” sometimes quite formal in design.

I have experimented with several irrigation products, including micro-emitters, “leaky” pipe, soaker hoses, and drip pipe. I prefer the very flexible soaker hoses available in most hardware and garden stores. They can be snaked in any configuration and are easily removed when it’s time to turn the soil. I use inexpensive chopsticks to keep the hose in place.

Bird netting   Soaker hose
Netting draped over the beds keeps birds from helping themselves.   Whimsical but useful, chopsticks hold the soaker hose in place. A hose bib allows controlled watering.
   
Now that redwood has gotten fairly expensive, many clients ask about using less expensive pressure-treated wood. I try to discourage them from making this choice because I’m not comfortable using chemically treated products around food crops.

It has been 20 years since we built the beds, and we are beginning to see signs of wear that indicate we need to begin rebuilding. Certainly, they have been a good value, having held up to blasting sun and year-round cultivation. Where there was once only concrete, the soil is now black and rich and teeming with earthworms. The eight beds make crop rotation easy to track. Everything I’ve grown in the garden has thrived.

Over the years, we have slowly removed the concrete paving between the boxes and replaced it with a thick layer of pea gravel that allows the little rain we get to percolate into the ground. And it crunches delightfully underfoot. Because the vegetable garden is the primary view from our kitchen, it has been an added pleasure to look out on the raised beds with their profusion of vegetables, herbs, and edible flowers spilling over the edges. Thanks to the raised beds, we can enjoy home-grown produce every month of the year.

Build the bed: plan, instructions, materials, and accessories
To make the corner posts, measure and cut the 8-ft. 4x4 into four 24-in. lengths. To make the long sides of the bed, nail three 8-ft. 2x6s one at a time to two corner posts; you will have boards stacked three high. The bottom board should be flush with the bottom of the post while the top board should end approximately 7-1⁄2 in. short of the top of the post, as shown in the drawing below. Repeat this step to form the second long side.

Cut the remaining three 2x6s in half so you have six 4-ft. 2x6s for the ends. Stand the two lengths with posts up, parallel to each other, approximately 4 ft. apart. Nail the 2x6 end pieces to the corner posts, three to each end. They should be aligned flush with the posts. The raised bed form is complete.

At this point, if you’re worried about gophers, moles, or voles, you can staple a 4-ft. by 8-ft. piece of 1⁄2-in. hardware cloth across the bottom of the box. This allows drainage and root growth but keeps the critters out.

Resist the temptation to sink the 4x4s into the ground; it’s really not necessary because the soil makes the boxes very stable. Also, buried 4x4s will rot faster.
Redwood raised bed plan
Click here or on the drawing to enlarge it. 
Materials list (per bed)

• One 8-ft. 4x4 redwood post for corners
• Nine 8-ft. 2x6 redwood boards for sides and ends
• One 1-lb. box of 16d (3-1⁄2 in.) galvanized nails
• 1⁄2-in. hardware cloth, 4 ft. by 8 ft.
Optional accessories

• Soaker hose and hose bib
• Support hoops
• Row cover fabric
• Clothespins
• Chopsticks
• Cloches

Learn more about designing and building raised beds...

by Linda Chisari
April 1997
from issue #8

1 | 2 All

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

posted in: raised beds, structures

Comments (16)

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 boxes...no 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 - http://www.suncast.com/productdisplay.aspx?id=647&pid=138) 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.
justachick
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:

http://www.finegardening.com/design/articles/pressure-treated-wood-in-beds.aspx
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
You must be logged in to post comments. Log in.