Raised beds are ideal if you don’t have a suitable area for growing plants in your garden. They also save your back because you don’t have to bend down as far when tending to plants. But when you are building your raised beds you need to make sure that you choose the right wood so they hold up against the weather.
This article will take you through my recommendations for some of the best types of wood, as well as some of the alternative materials and the things you should avoid.
Table of Contents
- How Thick Should Wood Be for a Raised Garden Bed?
- What to Consider When Buying Wood for Raised Garden Beds?
- 9 Best Wood Options for Raised Garden Beds
- 1. Cedar
- 2. Redwood
- 3. Pine (Cheapest Option)
- 4. Safe Pallet Wood
- 5. Black Locust
- 6. Douglas Fir
- 7. New Pressure Treated Lumber
- 8. Juniper
- 9. Cypress
- Can You Apply a Treatment to Raised Garden Bed Wood?
- Can You Paint Raised Garden Beds?
- Should You Use a Garden Bed Liner in Your Raised Garden Bed?
- What are Some Common Raised Garden Bed Mistakes?
- How Long Do Raised Garden Beds Last?
- What are Some Alternative Material Options for Building Raised Garden Beds?
- Materials to Avoid when Building Raised Garden Beds:
- Final Thoughts
How Thick Should Wood Be for a Raised Garden Bed?
Your raised garden bed needs to stand up to general wear and tear, so you don’t need to keep replacing it. Ideally, the wood should be at least 1 inch thick, preferably 2 inches. This will be robust enough to stand up to the weather and resist damage. However, the thicker the wood, the more expensive it will be, so consider your budget too. Try to buy the thickest wood that you can afford.
What to Consider When Buying Wood for Raised Garden Beds?
When deciding what type of wood you should use, there are a number of key things to consider.
Firstly, look at the price of the wood. Some options, like pine, will be much cheaper than rare hardwood. On the other hand, the cheaper options tend to be less robust. If you are building a lot of large raised beds, you need to pick a relatively affordable species of wood so you don’t go over budget.
Rot-resistance is one of the most important qualities to look for. Your raised beds will get rained on a lot, and they will be in constant contact with wet soil, so they are very prone to rotting. Some wood species have a natural resistance to rotting and mold due to the high oil content.
Wood that has a tighter grain is also resistant to rotting because it doesn’t let as much moisture in. Always pick a wood species that is naturally protected against moisture and rotting.
The appearance of the Wood
Your raised beds will be a central feature of your yard, so you should consider the appearance of the wood too. What does the grain look like? Is the color nice? Will it weather nicely or will it take on a dull color? For most people, appearance isn’t a top priority because raised beds are a functional addition, but it’s still something you should take into account.
Availability in Your Location
Finally, how easy is it to get hold of the wood in your area? If you pick a native species that grows just around the corner, you can easily find suppliers and the cost will be reasonable. But if you pick a rare species of wood that needs to be shipped in, the cost suddenly shoots up.
It also makes things more difficult in the future if you want to replace and repair raised beds and you can’t get hold of the same type of wood.
9 Best Wood Options for Raised Garden Beds
There are a lot of things to think about when selecting wood for raised garden beds. If you are a bit lost, my list of the best wood types will help you find the right option for your yard.
Cedar is a popular choice for raised beds because of its excellent natural resistance to rotting and insects. It has high levels of natural oils, which prevent moisture from seeping into the wood and rotting it. Cedar also has a very distinctive smell that insects hate, so it is naturally repellent.
Even when it is in constant contact with the soil, it will last for years to come without rotting. If you treat the wood to protect it first, it should last decades.
It has a simple straight grain and a reddish-brown color. It might not be the most interesting wood species, but it looks fine for raised beds. Getting hold of cedar is fairly easy as it is grown in North America and Canada, so it is relatively affordable when compared with teak or mahogany, for example.
Cedar is a solid choice for your raised beds because it’s readily available and fairly cheap, it looks good, and it’s incredibly robust.
Redwood is a more expensive choice, but it does have a lot of benefits. It is only found in certain areas, like the California coastline, so getting hold of it is harder and the price is higher as a result. That said, it is a very hard-wearing wood with great natural rot resistance. Like cedar, it has a lot of natural oils that repel moisture.
Redwood is an especially strong wood, so it will last a long time outside in the elements. However, unlike other high-strength wood types, it is very easy to work with, making it ideal for building your own raised beds.
The other big benefit of redwood is that it looks great. It has a nice deep brown/red color and a more interesting grain than cedar. If you have other redwood features in your yard, your raised beds will blend in nicely and you can make them more of a feature, instead of a simply functional fixture.
3. Pine (Cheapest Option)
If affordability is your main priority, pine is the way to go. It’s much cheaper than other options on this list and it’s easy to work with when building raised beds. However, it doesn’t have the same natural rot-resistance that other wood types do. If you leave it untreated, it won’t last very long at all outside.
But you can easily apply a treatment to protect it from moisture, and it will work perfectly on raised beds. You must make sure that you use a non-toxic treatment that will not seep into the soil and kill plants. Check out our guide on non-toxic wood treatments for raised beds for more information.
Even though pine doesn’t offer great rot-resistance, it is a very dense, strong wood. It grows in many countries around the world, and can be found throughout the US and Canada. In fact, it is the most common conifer in Canada, so it’s very easy to get hold of, and very affordable. Even though it requires a bit more work to treat the wood, pine is a brilliant choice if you want to build raised beds on a budget.
4. Safe Pallet Wood
Pallet wood is great for raised beds because it’s cheap to get hold of. Often, you can get pallets for free, and they are usually made from robust wood that has been treated to protect it against moisture. However, you need to be very careful about which pallets you use because some of them are treated with toxic substances that will kill any plants in your raised beds.
Pallets are marked with specific codes to indicate what they have been treated with and whether they are toxic or not. You will see a lot of different markings but the main thing you are looking for is the letter codes that give details about treatment methods. Look for the following codes:
- HT – Heat Treatment
- MB – Methyl Bromide
- DB – Debarked
- KD – Kiln Dried
You will usually see a combination of these codes. Heat treated pallets have been heated to kill any pests. Kiln dried pallets are also heated, but to a lower temperature. Debarked simply means that the bark has been stripped from the wood. The ones that you really want to watch out for are the Methyl Bromide pallets.
These have been treated with a strong pesticide that is harmful to your health and will kill off your plants. This treatment is no longer used, but older pallets may still be in circulation. Always check the marking and if you are unsure, play it safe and avoid using the wood.
You can also seal the wood for good measure. A strong clear coat will prevent anything from leaking out of the wood into the soil. Using a simple liner in your raised bed gives you more protection too.
5. Black Locust
Black Locust is a wood species that is often favored for exterior uses like fence posts, furniture, and even boat building. It is one of the hardest wood species available, and it’s very resistant to rot too. The strength of the wood makes it good for raised beds, but it can be more difficult to work with.
In terms of availability, it depends on where you live. In the eastern US, it is readily available and fairly affordable. But if you have to have it shipped in, the cost will increase quite significantly.
One of the great things about Black Locust is that it weathers nicely. Some types of wood turn a dull gray color that doesn’t look that attractive, which is not what you want for raised beds that take up a large portion of your yard. Black Locust turns a dark brown color with age, so it stays looking nice without the need for stain or paint.
Although it can be more expensive, Black Locust is not too unaffordable, it’s durable, and it weathers nicely, so you can keep it in your garden for years to come with relatively little maintenance.
6. Douglas Fir
Douglas Fir is another great budget option that still holds up against the weather. It’s relatively hard and has excellent natural rot-resistance too. Douglas fir has also become a more popular choice for raised beds in recent years because it’s very sustainable.
Some species of wood are relatively rare and there are environmental concerns about using them. Douglas fir, on the other hand, is abundant throughout the US, Europe, and the UK, meaning that it’s sustainable, easy to get hold of, and cheap.
It has a nice reddish-brown color to it and an interesting grain pattern, which is often very varied. After being outside for a while, it will start to gray somewhat. However, it takes on a nice silvery-gray rather than the dull gray you see with other wood species.
Douglas fir sits alongside cedar as a good, relatively affordable option for your raised beds.
7. New Pressure Treated Lumber
Pressure treated lumber is perfect for raised beds because it has been specifically treated with additives to make it resilient against moisture. It will last decades, even in direct contact with the soil. However, it’s crucial that you only use new pressure treated lumber.
The chemicals used to pressure treat wood have changed a lot in the last 20 years or so and older wood is treated with toxic substances. Prior to 2004, wood was treated with chromated copper arsenate (CCA), a substance that contains arsenic. This can leak out of the wood, causing health risks and certainly killing off any plants that are in the soil.
However, due to health concerns, companies stopped using CCA (it’s banned in some places) and switched to alternatives like alkaline copper quaternary (ACQ) instead. So, new pressure treated wood is perfectly safe to use and won’t harm your plants. As long as you use wood that is not treated with CCA, you should be fine.
Wood from the Juniper tree is less common for woodworking projects, but it’s actually a great choice for your raised beds. Like cedar, it has an odor that is naturally repellent to insects and it is incredibly rot-resistant too. It costs roughly the same as cedar, but it is a lot more durable and could last up to 50 years, even in direct contact with wet soil.
Juniper is a very sustainable wood and using it can actually help with maintaining ecosystems. There have been issues with juniper trees, which take in a huge amount of water, pushing out other plant species, and this has a knock-on impact on wildlife. In places like Oregon, USA, people are being encouraged to use more juniper to combat this problem. Junipers are also native to Canada too.
Currently, juniper isn’t a very common wood to use. However, it is becoming more popular because using it solves environmental issues and offers superior durability compared with other wood types that cost roughly the same.
Cypress is an incredibly strong, rot-resistant wood that is also very light. This makes it ideal for home construction projects like raised beds because building them is easy, and you don’t have to compromise on durability. Cypress is also a very reasonably priced wood, and won’t cost much more than cedar or redwood, even though it is a lot harder.
It can be quite a light colored wood but depending on how close to the center of the tree it was cut from, the color can be much darker. In some cases, it may even be close to black. In general, the darker the wood, the more rot-resistant it is because it has higher amounts of resin in it.
It can also sometimes be light with dark patches. These are the remnants of fungus that has affected the wood (this is known as pecky cypress).
Can You Apply a Treatment to Raised Garden Bed Wood?
Yes, using a non-toxic treatment will give the wood added protection against rot and insect infestations. Even if the wood is already naturally resistant, treating it simply means it will last much longer before you need to replace it. Just be sure that you are not using anything that will upset the soil and damage your plants. You can learn more about which treatments are best for raised garden beds here.
Can You Paint Raised Garden Beds?
Yes, painting a raised bed is a good way to improve the way it looks and get it to fit in with the rest of the garden better. It will also create a protective barrier on top of the wood, stopping any moisture or fungus from getting in. as
When painting a raised bed, always use a high-quality exterior paint. Interior products will not stand up to the weather. Although it takes longer to dry, an oil-based paint will last a lot longer before it needs recoating. They’re also better for painting over previously painted surfaces.
Ideally, you should paint the separate boards before you fix them together to ensure that you cover all areas and there are no gaps in the joints where water can get in.
Should You Use a Garden Bed Liner in Your Raised Garden Bed?
Yes, it’s always a good idea to line your raised beds. The liner will stop any pests coming in through the bottom and damaging our plants. It also helps water to drain away properly without taking the soil with it. Finally, they insulate the soil and help you keep a stable temperature. This is important in both the summer and the winter and without a liner, your plants could suffer due to extreme cold or heat.
There are, however, a few drawbacks. Firstly, replacing liners means taking all of the soil out of your raised bed. Secondly, if you don’t have the right material, it can prevent drainage. Finally, they can be damaged when digging in the bed. That said, with a bit of careful planning, you can avoid these problems.
You can line your raised beds with a variety of materials including plastic (tarps or sheeting), cardboard (old boxes), metal (chicken wire), or fabric (old burlap sacks). Cardboard is the cheapest option but it won’t last long. A plastic tarp is the most durable and offers the most benefits, but you do need to add some drainage to it by making some small holes.
What are Some Common Raised Garden Bed Mistakes?
There are a few common mistakes that people make when building and placing raised beds.
1. Not Adding Drainage
Without proper drainage, water pools up and the soil becomes saturated. Every time it rains, the plants become more waterlogged. Eventually, this causes the roots to rot and the plants will die out. You need to be able to control the amount of water that the plants have, so you need drainage. Make sure that you consider this when building the raised bed and putting a liner in.
2. Making It Too Big
Raised beds are a good way to maximize yard space and grow more things. But people often make the mistake of making them too big. If the bed is too wide, it is difficult to reach into the middle to water and trim plants when needed. Overcrowding a large bed with too many plants also means that they compete for water and nutrients and none of them grow effectively.
When building your raised beds, between 3 and 5 feet is the optimum width. Try not to make them too long either. It is better to build multiple smaller beds instead of one large one.
3. Measuring Wrong
This goes for any woodworking project really, but it’s a mistake people make more often with raised beds. You’re only making a simple rectangle or square shape, so people get complacent and rush the measuring up. But remember, if you get it wrong, you’re wasting wood and money. So, measure twice and then use the boards from your first bed as a guide for the rest.
4. Building In The Wrong Location
Location is everything if you want your raised beds to thrive. You need to find somewhere with enough space that you can easily walk around the beds to tend to the plants. But you also need a spot that gets good sunlight for most of the day. If you build them somewhere that is shaded most of the day, you will struggle to get anything to grow in there.
The best thing to do is take note of where the sun falls in the garden and then build in the spot that gets the most sunlight. If your garden slopes at all, think about drainage. Building it at the bottom of the slope will cause a lot of issues with pooling water.
How Long Do Raised Garden Beds Last?
This depends on the type of wood that you use and whether you treat it or not. If you use a good quality wood that is naturally rot-resistant, and you treat the wood to protect it as well, it will last decades. Pressure-treated wood and wood types with a lot of natural rot resistance will last 10-15 years before they start rotting. However, if you use a sealer to protect the wood, it will hold up for even longer.
What are Some Alternative Material Options for Building Raised Garden Beds?
Wood isn’t the only material that you can use for your raised beds and it’s always worth considering whether an alternative may be better.
1. Corrugated Metal Raised Garden Beds
If it’s durability that you want, corrugated metal is ideal for your raised garden beds. Galvanized steel is rust resistant as it has a protective layer of zinc on it, so it will last a long time without needing to be replaced. Although metal isn’t as attractive as wood planters, you can make them look good with a coat of paint.
2. DIY Rock Raised Garden Bed
Making your own raised garden bed out of rocks is so simple and they look great. You get excellent drainage with rocks too, and you don’t have to worry about rotting. Rocks will last indefinitely as long as you build the beds properly. The best thing to do is use wooden posts and string to mark the area and then start stacking the rocks to build the walls.
It takes a bit of trial and error and the rocks might fall but if you persevere, you can get them to fit. If you check online listings, you can often find free rocks.
3. Recycled Plastic Raised Garden Beds (Composite)
Composite wood is made from a combination of recycled plastics and wood fibers. It has the appearance of wood but it’s far more durable and rot-resistant, so it’s ideal for your raised beds. Composite is more expensive, but it will last a lot longer than any other type of wood out there.
4. Log Raised Garden Bed
Instead of milled cut wood, you can use full logs instead. You can still choose the same types of wood that you would use if you were using boards, and it’s a lot simpler to build. You just need to stack the logs up and put a few nails in to fix them. Logs can be treated in the same way as boards too, so they’ll last just as long.
5. Cement Bricks/Blocks
Cement is another good choice if you don’t want to worry about replacing your raised beds when they rot. A few cement bricks or breeze blocks make a simple raised bed and there is very little construction needed.
If you are concerned about aesthetics, cement blocks might not be the best choice but they are a great functional, cheap option. The porous nature of breeze blocks also means that you get excellent drainage.
Materials to Avoid when Building Raised Garden Beds:
1. Pressure Treated Wood Made Before 2004
The chemicals used for pressure treating wood have changed. Before 2004, chromated copper arsenate (CCA) was used, and this is a toxic substance. If you are growing plants in a raised bed made with old pressure treated wood, the CCA can leach into the soil and kill plants. It could also be a health hazard if you are growing vegetables to eat.
However, CCA is no longer used, so if you have pressure-treated wood made after 2004, you should be fine. Read our Sanding Pressure Treated Wood Dangers article here.
2. Pallets with Methyl Bromide, Colored Pallets, and Old European Pallets
Pallet wood can be a good choice, but only if the wood has not been treated with harmful chemicals. Methyl Bromide is a highly toxic treatment that is used on some pallets. Although it is no longer used on European pallets, old ones may still be treated with this dangerous substance. Colored pallets should be avoided too because the chemicals used to color the wood can potentially kill your plants.
3. Certain Rusty Metals
Rusty metals can potentially damage plants but, in some cases, rust can actually be good for plants because it makes the soil more iron-rich. It all depends on the amount of rust and any treatments you have used on the metal. A large build up of iron is likely to kill plants, so incredibly rusty metals are a problem.
If the metal is painted and it rusts, toxic substances in the paint will leak into the soil and kill plants. You can avoid this problem by using galvanized metals to bud your raised beds.
4. Railroad Ties
Old railroad ties are often used for DIY projects because they’re cheap and robust, but you should never use them for raised beds. The wood is treated with creosote to preserve it and protect it from the elements. Creosote is highly toxic and will quickly kill plants and destroy the soil.
Some people suggest using old tires as a quick way to make raised beds. Just fill them up with soil and put some plants in. Sounds like a great idea, right? Actually, not so much because tires contain a lot of potentially damaging substances like arsenic, lead, acetone, benzene, and mercury, which can all leach into the soil. Some people find that tires are ok and their plants survive, but it can be a risk.
6. Electricity/Utility Poles
The reclaimed wood from electricity and utility poles is another affordable option for DIY projects. However, it is also treated with a lot of harsh chemicals. This does make it last a lot longer outdoors, but it also makes it dangerous for plants.
Choosing the right wood for your raised beds will help them last longer and protect your plants. When you are selecting wood, there are a few key things to consider; firstly, think about the durability of the wood and how rot-resistant it is.
Secondly, if you are using reclaimed wood of any kind, make sure that you don’t use wood that has been treated with toxic chemicals. You can also make your raised beds last longer if you treat the wood with a sealer or paint it.
Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.