Build Your Own Raised Beds

Year-old redwood raised beds with drip irrigation holding calla lillies.

Did you plant some flowers and vegetables, planning to have a garden that would make the neighbors green with envy? You hit a slight snag, though: the gophers acted like a salad bar was open. You lost first one plant, then another and soon, all of them were in gophers' bellies.

Raised beds offer a simple solution to theses pesky pests. The best part is even novices can build and install a single basic raised bed in a weekend.

Building raised beds is a matter of planning and preparation, construction, installation and irrigation.

Each step is important but the first step is crucial to your success or failure.

Tools include a Skilsaw, carpenter's square, tape measure, cordless drill and
bits, screwdriver, safety goggles and ear protection

Step 1: Planning. Tools required: a tape measure, pad and pen or way to draw out and record your plan. You will also need access to a pick-up truck for hauling lumber and planting soil.

Planning begins with measuring where the raised bed will go. Be sure to allow room to insert the bed and space to accommodate a water line.

Tip: Water flows downhill. Do not have the top of your bed more than 12 inches above your water valve. Ideally, the bed should be lower in elevation.

Planning includes orienting the bed for sun exposure based on the type of plants you want to grow. It’s a lot easier to make this adjustment now than after you’ve built your bed.

Once you’ve measured where the bed will go, modify your design to reflect 8-foot wood lengths. Lumber comes in a variety of sizes, typically starting at 8 feet. Other common lengths are 10 feet, 12 feet, 16 feet and 20 feet. Eight foot boards fit in the bed of a full-size pick-up truck, while 10s and 12s stick out a bit. Anything over 12 feet can be tough to transport without a lumber rack.

Using 8 feet as a base, consider bed sizes such as 8 feet by 2 feet, 8 feet by 4 feet, 6 feet by 2 feet or 4 feet by 4 feet. Your final width may be slightly narrower, but these measurements give you a starting point.

You will also need corner posts, and for anything longer than 4-6 feet, center support posts. Use 2 by 4-inch posts when using “1 by” thick wood panels (this wood measures about .75 thick), 4 by 4-inch posts for “2 by” (1.5-inch thick) panels. Your posts should site about 6-8 inches below the bottom of your bed for stability.

Also look at how hard and level the ground is, if you are going to set your bed on it or slightly into it. The ground needs to be firm enough to support the weight of the box, dirt, plants and water on top of it. Muddy or extremely sandy soil is a bad location.

Now you have your bed’s site planned and wood lengths calculated. It’s time to move on to the Construction phase, which has three parts: cutting wood, assembling the bed and gopher-proofing it.

Step 2a: Construction. Tools required: a saw, carpenter’s square, tape measure, pencil and a flat and level surface. Safety equipment: Ear plugs or ear guards, clear goggles and gloves.

Pine posts, redwood, drill ready for pre-drilling, tape measure, gloves and
in foreground, a long clamp for warped wood. A stack of end boards sits
at left.

Start by measuring your side panels with your tape measure. Draw lines by placing your carpenter’s square along one straight edge then marking your cutting line across the board.

If you are going to make more than one cut from a single board, make your cut marks starting from one end then the other. This assures you of at least one straight, square edge.

Now that your lines are drawn, make sure your boards are flat and secure. Boards break, warp and can hurt you by bouncing back when the weight becomes uneven.

Next, put on your safety gear and start cutting. Have the blade spinning before contacting the wood.

Tip: When using power tools, always follow the manufacturer’s recommendations and never place your fingers close to a blade. Also, turn off your power saw between cuts as an additional precaution.

When you’re done cutting, pile the boards into stacks for long and short sides. Stand them on end. If one board is noticeably longer or shorter, measure it and either cut or replace it.

Your wood is ready, so it’s time to advance to the assembly stage.

Step 2b: Assembly. Tools required: a drill, Phillips head screwdriver bits, wood bits one size narrower than the screws you are using plus a manual screwdriver. Optional: long wood clamp.

Start by placing your posts on a flat, level surface. Align the top and outside of your longest top side board (if going more than one high) with the top and outside of your posts. If the top and outside of your top board is square to your posts, the bed will be square. If either side is off, the entire bed will be uneven.

Pre-drill holes for your screws. Predrilling helps reduce the amount of wood that will be split.

Your pre-drill holes should be slightly shorter and narrower than your screws. This makes driving your screws easy, but still makes the holes tight enough for the screws to hold securely.

Drive your screws in most of the way. If they stick out slightly, that’s easily fixed. Do the top board, left, middle (if longer than about 4 feet) and right.

Using the same procedure, align the second board with the top one butting up against it. If there is a gap at one end between the top board and second board, consider using a long wood clamp to force them together. Make sure your left side screws are in pace before attaching the clamp. Allow 2 or 3 screws per board per post. Once your two long sides are completed, use available materials—trees, concrete blocks, strong boxes in your garage—to support them. Now start attaching your narrow sides using a slightly different method than above.

First, align the top and outside with a long side. Pre-drill the top hole and insert your screw. Next, push, pull or tap the right long side so the top and outside of the narrow board lines up with it. Now attach the top screw. Make sure your top narrow board is square with both long sides.

With the top screws attached to both left and right sides of your narrow board, add the remaining screws to it and secure it. Now switch to the opposite end and repeat. Check to be sure the ends are square.

When all screws are in place, use a hand screwdriver to firmly tighten them. Using too much pressure will cause the wood to split.

Your basic raised bed is now complete. If gophers are not a problem or you are using it for vegetation with long roots, stick the sucker in the ground.

However, if gophers consider your plants fast food, move on to the next step.

Chicken wire installation.

Step 2c: Gopher proofing. Materials required: chicken wire, 3/8ths long staples. Tools: staple gun, wire cutters. Safety equipment: gloves, a long-sleeved shirt.

Start by turning your bed upside down.

Align one end of your roll of wire with the end and one side of your bed, allowing about 1 inch of overlap. Laying the wire over your first pair of posts, use your wire cutters to clip three sides of a hole just large enough for the post to slip through.

Use staples to attach the wire to one narrow end then lay the wire over the remaining posts. Cut those holes. Staple the far end then cut the wire. If your bed is narrower than the wire—it typically comes in 4-foot widths—trim down the long side as well. Now staple the long sides, with staples about 2-3 inches apart.

Tip: You want the wire to be tight, but not so tight it puts tension on the wood. Slightly loose is better than too tight.

While chicken wire will not keep all gophers out, it will make it more difficult for them. That's the idea: let them move somewhere else.

Congratulations. Your raised bed is now ready to be installed.

Phase 3: Installation. Tools required: bubble level, a shovel, possibly a “busting bar” for rocks and hard dirt, wheelbarrow for moving dirt.

Position the bed where you want it to go, then lightly tap the posts. This will mark the soil. Now dig holes for each post. Once the bed is touching the ground, remove or add dirt to level the bed.

If your ground is uneven, start by having your bed touch the ground at its lowest point. You will need to remove dirt from the higher area—or shift it to the lower point—to balance your bed.

Your bed is now set, but empty. If you have gopher problems, consider adding a layer of rocks atop the chicken wire. Larger rocks make it harder for gophers to get in. Fill your bed using a mixture of regular dirt and amendments such as potting soil.

I prefer to use regular dirt—so long as it is not either pure sand or solid clay—for the lower two-thirds, topped with a mix of potting soil and dirt for the top third bringing the soil mix to within the top 1-3 inches of your bed.

Tip: Liberally water your raised bed before adding your watering devices and plants. This will compact the dirt, allowing you to add more if needed.

At this point, some people add their plants and stop, preferring to water by hand or let Mother Nature do it.

If you live in an arid climate, though, irrigation is essential.

PVC 3/4-inch feed line to 1/2-inch to 1/2 inch drip tubing to 1/4 inch sprinklers.

Phase 4: Irrigation. Tools required: a pair of regular pliers and a drip irrigation hole punch. Materials: a timer that attaches to a hose bib, a female to half-inch drip connector, half-inch and quarter-inch drip tubing plus drippers and sprinklers to suit. The materials you will need depend on how many raised beds you have, their spacing and the type of plants you are using.

Start by connecting a watering timer to the nearest hose bib (outdoor faucet), then attach a garden hose to it. Next, attach the female to half-inch drip connector to the end of your hose. This device is made with black plastic and has a green ring on the end. You screw one end onto your hose then wriggle your half-inch tubing into the other, going in at least 1-2 inches for a secure fit.

For a single raised bed, run the half-inch tubing from your hose down the center of the bed to the far end. Cut it off and use a clamp (it looks a figure eight) or male hose connector (it looks like the end of a hose you screw onto the faucet but this version comes with a cap) to close it off. You can use either small rocks or special large metal staples to keep the half-inch line straight but allow a little play.

Now use your hole punch to make holes in the half-inch line and using small connectors (often supplied with spike-style drip sprinklers), connect your quarter-inch line to your half-inch. Place these drip sprinklers close to your plants then adjust their volume down or up so most of the water goes only on your plants.

It’s always a good idea to ask your local nursery or hardware store which type of drip devices to use with your plants.

Tip: Some people have problems getting the quarter-inch connectors into the half-inch tubing. Use pliers makes this task far easier.

And now it’s time for the final phase.

Three new beds join an older one (far left).

Phase 5: The End. Tools required: a cold beverage, anti-inflammatories and a cold shower or hot bath. Take a load off and congratulate yourself on a job well done.

Do some of these terms seem confusing? If so, read the accompanying story for explanations and more tips.

Carpentry Terms, Tips, Tools and Techniques for the Homeowner

Some of the terms used in the preceding guide to building raised beds may confuse you. Fear not for this brief article will help.

What follows is a list of some common terms, tips, tools and techniques to help you build raised beds. They also apply to many other home carpentry projects.

Use what you need. If you still have questions, ask a professional.

This bed uses 2-by fir attached to 4x4 posts with lag screws.

Wood

Four types of wood are often used in raised beds: redwood, pressure treated fir (or other wood), untreated fir and untreated pine. Each has its advantages and disadvantages.

Redwood can withstand direct contact with the soil and last at least 10-20 years. However, it often costs about three times more than untreated pine or fir.

Untreated pine or fir generally lasts 5-10 years, longer if sealed with a clear coat. This tends to be the least expensive material because it is frequently used in home construction.

Year-old planters are made with redwood. Pressure treated
wood is used to line a walking path, not in planting beds.

Pressure treated wood is similar to redwood in terms of both durability and cost. However, it is treated with arsenic so never use it with anything you plan to eat. Using it for flowers, or to outline a walkway is fine. But never use pressure treated wood when raising fruits or vegetables.

Wood sizes are often misleading to novices. When someone talks about a “2 by 4,” they are talking about a piece of wood in its raw, untreated size. Milling reduces these dimensions by about 25 percent, making a 2 by 4 actually 1.5 inches thick by 3.5 inches wide.

Be wary of warps and crowns. Warps will cause the wood to bow in or out. Crowns will cause it to bow up or down at one end. You can correct for a slight warp by using screws. Crowns are harder to fix.

Saws and Cutting

Wood needs to be cut to make your raised beds. Some stores and lumber yards will cut your wood at no charge. Others charge a nominal fee. If you are uncomfortable working with power saws, have the pros do it but be sure to carefully measure what you need first.

If you are going to cut the wood yourself, consider buying what’s commonly known as a Skil ® saw with a blade 5 inches or greater in diameter. These saws give you a lot of flexibility but require a steady hand and care when using.

When attaching your wood, also try to use at least one end with a square cut. This is a cut with a perfect 90-degree angle, like what you will get from a lumber yard. Some homeowners' do not cut perfectly straight, which can throw their beds off when assembled. Using square cuts on at least one edge results in a better bed.

Drills and Screwdrivers

Your typical small cordless screwdriver does not have enough power for this type of task. Either get an 18-volt or greater cordless model or a fairly powerful corded electric drill.

Since assembling the sides of your raised beds involves pre-drilling holes then inserting screws, you might find it efficient to have two drills and load one with a drill bit slightly shorter and narrower than your screws. Use the second drill for driving in the screws.

Measuring and Leveling

One of the most frequently used tools in any carpenter’s kit is a carpenter’s square. This simple device has a 12-inch metal ruler, a simple bubble and a 45-degree stop. Use this for drawing cutting lines and for perfectly positioning drill holes on wood up to

Larger squares (they look like a large metallic “L”) are better when working with bigger pieces of wood such as sheets of plywood.

Bubble levels come in a variety of lengths. A 2-3-foot bubble level is sufficient for most home construction projects. Longer levels, such as 6-footers, are only needed for major construction projects.

Screws and Hardware

You can attach the sides of your raised bed to your posts using nails, screws or lag screws.

A personal preference is avoiding the use of nails because too much force can split boards, costing you money and time.

Your typical Phillips head wood screws work just fine most of the time, provided you make sure they are wider and longer than the drill bit used to pre-drill their holes. Consider using regular screws when building raised beds with “one by” wooden sides.

Lag screws are larger and far heavier than normal screws. You will need a socket wrench to drive them. Personal preference is using lags when working with “two by” thick wood and 4-by-4-inch posts because lags have the strength to handle the additional weight.

If are going to use lag screws, pre-drill a 1-inch diameter (or smaller) hole about a half-inch deep in your side board, then pre-drill your screw hole. The larger diameter hole adds depth to screw hole and keeps the screw head flush with the outer edge of your board.

You can also use brackets but they can add a substantial cost to your project.

Safety Equipment

Power tools are not forgiving. The slightest amount of inattention can cost you a finger or worse. Splinters can fly up and destroy an eye. Boards can bounce back and clobber you. Loud noises, such as saws, can damage your hearing.

For those reasons, it’s always a good idea to wear gloves, clear plastic eye protectors and either foam earplugs or slip-on hearing protectors. Keeping a solid grip and even pressure on wood being cut will eliminate the bounce backs.

There Is No Substitute for Experience

Building raised beds is a simple project for anyone, even novices. However, pros know what to and how to do it so they are much faster and more accurate. When in doubt, talk to people and hire a pro.