Are Landscape Timbers Treated? A Helpful Guide

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While gardening one puts lots of thought and care into planning what goes in their landscaping. Landscaping timbers are no exception to this rule. Before you begin placing timbers in your landscaping project, be sure you know what your timbers are made out of with this helpful all-inclusive guide!

Landscaping timbers are produced from the soft center of the trees. This center wood is typically chosen for making plywood but makes for absolutely beautiful landscaping timbers as well. Depending on what type of landscaping timbers are placed in your yard and where they are sourced, they may or may not have been treated by harmful chemicals.

Landscaping timbers can be used in order to build decks, walkways, raised garden beds, or even to simply create a divider between plants and the rest of the yard. However, with our children and pets spending lots of time in our gardens, harmful chemicals should have no place in our yards. At times knowing what is in your landscaping timbers can prove to be quite difficult. This guide below will help you to learn what goes into making your landscaping timbers, the best ways to use them in your garden, and safe alternatives to using treated landscaping timbers around your property!

What’s in your Landscape Timbers?

First of all, what even is a landscaping timber?

When you first hear the word, you may think it refers to the small wooden chips placed underneath play structures or in the yard landscaping areas. However, landscaping timbers is actually referring to the small logs that are commonly used to build structures in yards.

A landscaping timber can be anywhere between three to six inches thick and are most often round on two sides while flat on the others. Since the timbers are designed this way, they are easy to stack and still give off a clean, finished look in your garden. However, not all landscaping timbers will come with rounded edges so it will all depend on the look and feel you would like for your garden which timbers you should choose.

Why do most gardeners choose to use treated woods over untreated woods? Well, in the case of a raised garden bed, the soil and water will begin to break down untreated woods rather quickly, leading to rot and moss build up. However, the treatment on the outside of the timbers will help the wood last longer and keep your gardening projects intact.

So what are they made of?

Now that we know what a landscaping timber actually is, let us discuss exactly what they are made of and if they are even safe for use in your garden.

Rather than using older landscaping timbers, we suggest looking for some of the newer pieces. This is due to the fact that before the year 2004 most landscaping timbers were soaked in the chemical arsenic.

The arsenic was used in order to help the wood last longer against the effects of nature’s elements. However, since arsenic is known for being poisonous, make sure that your timbers were made after the year 2004 just to be on the safe side (especially if you have pets or kids that will come in contact with the timbers often).

While at first, the treated timbers did not pose a problem, after a few years the chemical treatment began to seep into the soil around them and then affect the plants growing there as well.

Worried that your landscaping timbers may have been treated with this arsenic mix (known as CCA)?

Landscaping timbers treated by the CCA chemical are easily distinguished by their greenish tint. You will best be able to see the tint on the cut sides of the wood.

Keep in mind that the older the wood is the more likely that the green tint will have faded. If you are ever unsure of the year of your landscaping timbers or what they have been treated with, we suggest disposing of the old timbers and purchasing (or making) new ones. Remember, it is better to be safe than sorry!

CCA treated timbers while not useable for all landscaping projects can still be used in constructing decks or patios. You should just avoid using these timbers for garden beds (especially ones where vegetables or fruits are grown).

Since 2004 all other treated types of landscaping timbers have been deemed safe for garden and home use!

In the event that you do not want to re-do the landscaping timbers throughout your vegetable garden, you can protect the soil and plants from the chemicals by placing either a plastic ring inside the garden bed.

If you want to use landscaping timbers for your vegetable garden, there are also several untreated types of wood that will work perfectly in your garden. Some of the most commonly untreated types are juniper, cedar, and redwood timbers.

While these natural timbers may not have the same coloring available as the treated timbers, you can always paint their exterior to match the aesthetic of the rest of your garden.

The natural timbers will need to be replaced as soon as they begin to rot in order to prevent termites and other bugs from eating away at the landscaping timbers.

How to Treat Your Own Landscape Timbers

If you want the benefit of knowing exactly what your landscaping timbers are treated with, you can always treat the timbers yourself!

Doing so might be a bit more difficult but is completely possible and is well worth the extra work.

The first thing you will need to do in order to treat the timbers is to wash all the untreated sides of the wood with an oil solvent. You can apply the oil with a rag by rubbing until the oily feeling is almost completely gone.

Do you not have any oil solvent lying around the house? Click here to order some of your own!

Once you have oiled each side of the timbers, you will need to sand off the sides as well. Keep sanding until the oil layer has been completely removed. We suggest a higher grade of sandpaper in order to get the job done faster.

It is at this time that you are able to paint or stain the wood. Painting or staining your landscaping timbers can be done just like any other wood.

After the paint or stain has fully dried, you can then apply the treatment to the wood. Do so with a paintbrush or rag and a respiratory mask. Not sure where to purchase your landscaping timbers treatment, click here to get a quart of your own now!

When choosing what to treat your landscaping timbers with there are a few tips to keep in mind. Any treatment containing copper, arsenic, or chromium should not be used in any gardening beds that are going to have food grown in them.

For these garden areas, you should look for a more natural wood treatment.

Where to Place Landscape Timbers in your Yard

While you can hire a contractor to place all of your landscaping timbers, the cheaper option will always be to place them yourself.

Before placing any landscaping timbers in your yard, no matter if you are dealing with treated or untreated timbers, you should be sure to use gloves. Not only to protect your hands from the chemicals but from the splinters as well!

Before you purchase any landscape timbers for your lawn, accurately plan out and measure the area you will need to cover. Whether this is a wooden walkway, a timber made deck, raised garden beds, or some garden steps decide exactly how you want the project to be completed and how much wood it will require to finish it.

The best way to get the correct measurements is to place some edging stake where you would like the landscaping timbers to be placed, then run some yarn around the stakes tightly, and measure!

Once you know how much wood you are going to need, you can run to your local hardware store and pick up the correct amount (and type) of landscaping timbers you need.

Prepare to place the timbers by digging the soil out of the area where they will be placed in. Be sure that you stick closely to the line you set up with the edging stakes and yarn, otherwise your timbers may be placed crooked which could possibly throw your measurements off as well.

Remember that the installation process will be much easier, and look much better, if the edging is both straight and level! In order to get a more straight edge, we suggest using a hand edger. Order the AMES Saw-Tooth Border Edger by following this link!

If you want to get the job done a little bit faster, you can even try using an electric trencher or lawn edger! The WORX Electric Lawn edger & Trencher is sure to get the job done. Click here to start using one today!

Once all the dirt has been cleared and the ground has been leveled (you can use a rake and a shovel to do this), be sure to pack down the edges either with a tamping rod or simply by walking on top of them. After that is done, you are finally able to begin placing your landscaping timbers.

Before you begin connecting pieces, we suggest laying out the landscaping timbers along the edge to double-check that your measurements are in fact accurate.

To prevent any weeds or other plants from growing in your landscaping, lay down some landscape fabric. The fabric should just reach the edge of the landscaping area (not long enough to hang out the end, but just long enough to be held down by the timbers you place).

When placing the fabric be sure that you do not leave any gaps between the sheets. You can hold the landscaping fabric sheets with some staples or small stakes.

While landscaping fabric is completely optional, placing it will significantly cut down on the amount of time you spend pulling weeds and other plants out of your landscaping!

When you begin placing your landscaping timbers, we suggest starting off in the corners. You will want to use a drill in order to secure the pieces and the corner braces together.

If the corner you construct is not a perfect 90 degrees be sure to use a protractor in order to get an accurate cut.

Once again verify that the timbers line up and that there are not any pieces too long or too short. If there is a piece that is too long you will need to cut it and retreat it using the steps listed in “How to Treat Your Own Landscaping Timbers” above.

You are then able to place the rest of the pieces, connecting them with mending plates. As you place your landscaping timbers, be sure to use a level continually as you go.

Once you have the timbers placed, you can secure them into their places by using rebar. Simply pound the rebar in a couple of feet apart, being cautious of any underground wiring or sprinkler systems. The top of the rebar should not be higher than the top of the landscaping timbers.

Learn more about how to install your landscaping timbers by reading this article by Improve Net!

Safe Alternatives to Landscaping Timbers

If you want to avoid the worry of placing any harmful chemicals in your landscaping, you can always use a safe alternative instead!

Some safe alternatives to treated landscaping timbers include cinder blocks, bricks, sandbags, metal basins, and even rubber logs! Keep reading to learn how to use each of these items in place of landscaping timbers.

Cinder Blocks and Bricks

Cinder blocks and bricks work in almost the same way when it comes to landscaping. You can place the cinder blocks or bricks to form raised garden beds, pathways, patios, and garden steps!

Just like using landscaping timbers, you should start by measuring out the area for your garden project by placing stakes and yarn around the perimeter.

Since cinder blocks are a little bit bigger than timbers or bricks, you may need to dig a deeper trench to place them in.

If you are building a cinder block path, it will be extremely crucial that you level out the land and the bricks. Make the path more stable by filling the blocks full of either sand or dirt.


While a sandbag used in place of your landscaping timbers may seem like a silly idea, sandbags actually work well for insulating raised garden beds.

Sandbags used in place of landscaping timbers are often referred to as earthbags. These earthbags are filled with the soil from the garden and then stacked in rows on top of each other. The mix used to fill your bags should be fluffier, richer soil as opposed to clay.

In order to make your walls more stable, place each row staggered from the one below. An earthbag wall can be durable enough to stand up to snowstorms, high winds, and even flooding!

Between the first and second row of sandbags, you should place either one or two rings of barbed wire. The wire will hook on the two rows and make the garden bed stronger.

To further the strength of your earthbag wall, pat down the bags with a hand tamp.

While just plain sandbags may be an unattractive choice for your landscaping, you can make the garden bed look more appealing by coating the bags in plaster and then painting them to match the aesthetic of your yard.

Once the plaster and paint are dry you can add the soil and your plants to the garden bed! The plaster will not only help the garden bed look better but it will also help the wall last longer too.

Metal Basins

A timeless gardening look is the use of metal basins for gardening or flower beds.

Whether you use a metal wash bin or a galvanized bucket, the only steps you need to do are place the bins, fill them with soil, and then add your flowers and other plants!

Metal basins do not require any landscaping fabric or worry about any dangerous chemicals. Not to mention that metal basins are less likely to experience weed growth.

Rubber Logs

Do you still want the classic look of landscaping timber but do not want the hassle of chemicals and decay? A unique thing to try in your garden is synthetic landscaping logs.

You should consider using synthetic landscaping timbers if you live in an area that experiences extreme weather that is more likely to rot away at natural landscaping timbers.

These logs are often made out of recycled plastic or rubber and are durable enough to last not only years but nearly decades! By placing synthetic timbers in your garden you will not have to worry about checking your timbers for rot or mold build up.

If you are looking to save money on your landscaping, using landscaping timbers, either natural or synthetic, is likely to be the cheapest material for you to use.

Do it Yourself Projects with Landscaping Timbers

Not sure how to use landscaping timbers in your yard? Here are a few, fun and unique projects sure to bring more curb appeal to your lawn.

Garden Steps

Adding garden steps to a slanted yard can help break up areas of the yard and make it easier for people to walk down the lawn.

Not only will placing these steps in your garden make it easier for people to move throughout different levels of your yard, but it can act as a retaining wall in order to protect the area from soil erosion.

The best part about adding garden steps to your yard is that they are easy enough to build that almost anyone can do it!

Start the process of building your garden steps by planning exactly where you would like them to go. Then measure out the area and collect the landscaping timbers needed.

Plan out where the steps will go by placing stakes and yarn along the edges. Then dig out the area and pack down each of the step levels with a tamping rod. Be sure that each step is level and tightly packed down.

Once you lay down the timbers, you can ensure that each landscaping timber remains in place by pounding them into place with a sledgehammer. At this point, you should again check to see that the steps are level.

You can make sure that the steps remain in place by driving a metal rod through the top of one timber into the one below.

Watch the video below to see exactly how to build steps out of landscaping timbers!

Deck Frame

A deck or patio is the perfect place to spend your days relaxing out in the sun. With a few landscaping timbers, you can build the perfect deck of your own.

Rather than taking the time to dig concrete footings for your deck you can simply use treated landscaping timbers as the frame.

The first thing you will need to do in order to build your deck is clear an area for the deck to go. This area will need to be level in order to build a proper patio deck.

Once you have found a level area, use the stakes and yarn once again to measure out the area. Simply layout your landscaping timbers in a frame on the area for the deck, securing them both together and to the ground.

After your frame is constructed, you can lay the decking across the top, attaching the boards with either screws or a nail gun.

Read how these people constructed a deck frame of their own out of landscaping timbers at Cottage At The Crossroads.

Split Rail Fence

The number of different ways one can use landscaping timbers is unbelievable!

Rather than just using landscaping timbers for garden boxes and landscape lining, you can use the landscaping timbers to build a fence around your lawn.

Using landscaping timbers to construct your fence will give your lawn and landscaping a more rustic and country-style look. You can use the timbers as both fence posts and railings!

Start your fence off by digging the holes for the posts. The holes should be deep enough that at least a fourth of the post to be buried in the ground.

Need some extra help digging the holes for your fence? Click here to get the AMES Post Hole Digger to help you build a landscape timber fence for your lawn.

Once you have all of your post holes dug, you can begin setting the posts in their places. Be sure that a flat side of the post faces the inside of your fence, fill the area around the post with dirt, and then pack it down tightly with a tamping rod.

If you want to have an extra-sturdy fence, rather than refilling the holes with dirt you can fill them with concrete. Whether you use concrete or dirt to fill the holes, double-check that each post is level before they are permanently in place.

Once you have your posts all set in place, measure how far above the ground you want each level of railing to be. You will want each of the rails to be evenly spaced across the entire fence.

After you have marked the measurements on each of the posts secure the rails on with either screws or nails.

Do you want your landscaping timber fence to protect your lawn from small animals? Line your fence with some chicken wire and fence wiring staples.


A pergola provides shade for when you are spending time out in your yard. Not only will a pergola make your time spent in your yard more enjoyable, but it is so easy to construct you can even do it yourself!

For those who are unsure of what exactly a pergola is, it is essentially a wooden patio cover.

Start off by choosing where the pergola will be placed in your yard.

The first thing you will need to do is dig out four deep holes for the posts of your pergola. Place gravel at the bottom of the holes in order to let water drain out.

Place the posts in the hole and ensure that they are level. Secure the posts into place by pouring cement into the holes. Keep the posts level while the cement dries by attaching some temporary braces.

Connect the four main posts at the top with some joint beams. Be sure to hang them up with strong and durable lag bolts.

Once you have your joint beams hung up, you can begin hanging up the stringers. Make sure the stringers are evenly spaced out across the top of the pergola.

That’s really all there really is to it! However, if you want to skip the trouble of measuring and cutting out the landscaping timbers for your pergola, you can always purchase a pergola kit. Click here to get your own pergola kit for your lawn!

If you want to be able to use your pergola in both rain and shine, you will need to add a cover on top of the stringers for extra protection. Add a little bit more sun coverage to your garden pergola, click here to order the ALISUN Sling Canopy for your yard!

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