Join Waitlist We will inform you when the product arrives in stock. Please leave your valid email address below.
All Things Garden,  Beginner Basics

7 Ways To Make Wood Garden Beds Last: Nontoxic Sealer & More

There are many benefits to gardening in raised beds or planter boxes: the improved ergonomics, clean appearance, ability to fill them with quality soil and compost, and it’s easier to block out pests. I love raised beds! Yet one of the few drawbacks is that they don’t last forever (and, they aren’t exactly cheap). So, protect your precious investment and follow these 7 ways to make wood garden beds last longer! We’ll talk about how to seal garden beds, lumber choices, drainage and more.

I’ll admit, we never sealed our garden beds in the past. They’re made from super durable heart redwood, after all! However, once we moved to our new homestead and began building our “forever garden” (and felt the rude awakening of not being in our 20’s anymore during the laborious process) I thought to myself: I want to make these garden beds last a LONG as physically possible. 

In fact, we seriously contemplated getting some awesome Birdie’s galvanized metal raised bed kits instead. Those things should last forever! (And you can save 5% with code “deannacat3”). But in the end, my love for the look of rustic wood won that battle, so here we are: we just finished building 19 new redwood garden beds, sealed and siliconed this time. Do it once, and do it right.

After reading these tips, pop over and follow our step-by-step guide on building wood raised garden beds!

A large gravel garden area that is lined with large rocks on the border with many wood raised garden beds evenly spaced throughout the area. There are oak trees in the foreground and background as well. The beds are full of soil but have yet to have anything planted inside.
Our brand new garden. I can’t wait to see her planted and full of life!


1) Choose wood that is naturally long-lasting 

One of the best ways to extend the life of raised garden beds is to use quality, long-lasting lumber right from the start. Cedar and redwood are two excellent choices, as they are both very dense and durable. Thanks to their high tannin content, both cedar and redwood are naturally resistant to rot, mold, and insects – including termites. Heart redwood lumber (what we use to build our raised beds) is even more indestructible than common redwood boards. 

Garden beds built from untreated cedar or heart redwood can last well over a decade on their own – likely much longer, depending on the climate and other conditions. The 7-year old untreated heart redwood beds in our old garden are still in excellent condition. I’ve also heard stories of friends’ redwood beds lasting well over 20 years! Then, if you follow the other ways to make garden beds last longer as described below, you can extend their life by several years more.

In comparison, garden beds made of softer woods like Douglas fir or pine can rot out and decay within just a few years. Don’t be tempted to use pressure treated lumber (usually treated pine) to make garden beds last longer either! In addition to containing undesirable chemicals not ideal for organic gardening, the lifespan of treated wood is less than cedar or redwood anyway! Especially when it is in constant contact with soil and moisture – as it will be in your garden.

Three garden beds of varying ages and color are sitting atop gravel hardscape. Two of the older beds are planted out with bok choy and various greens. The smallest and newest garden bed has just been topped off with soil. There are various salvia, cacti, fruit trees, and other perennials in the background.
Heart redwood garden beds at various ages in our old garden. The big bed in back (most gray) is about 6 years old in the photo. While the color has faded with age, it is still perfectly structurally sound. The bed in the foreground is 1-2 years old, and the smallest one to the left was brand new.

2) Use wide planks and thick boards

Choosing wide lumber planks is another excellent way to extend the life of wood garden beds. For example, a raised bed constructed out of 2×6” boards will last longer than one made from 2×4”s. Eight, ten, or twelve-inch wide boards are even better! Raised beds are most susceptible to rot in the seams between the boards, where moisture collects and air is scarce. By using wider planks (and thereby reducing the number of seams in the bed overall) it is reducing surface area and places for water intrusion. 

The same idea applies to board thickness. While 1-inch thick boards are often more affordable (such as cedar fence boards, which are actually only ¾” thick), the raised bed will not last as long as one constructed with 2-inch thick boards. Plus, thinner boards are more likely to bow or even crack over time under the pressure of heavy wet soil pushing against them. Last but not least, thick 4×4” corner supports will last far longer than using 2×4’s or other smaller wood in the corners.

A concrete patio is being used to construct garden beds. There are pieces of 2x6 boards and 4x4 boards as well. One bed is laying on its side, fully constructed. The patio is lined with older garden beds that are filled with various vegetables. Two chickens stand in the yard beyond, visible between two of the beds that create a gate. Using cedar or redwood help make garden beds last longer.
We make our heart redwood raised beds with 4×4 corners and 2×6″ boards. These beds were extra tall, but now we usually make them 3 boards high. We haven’t been able to find 8″, 10″, or 12″ tall boards here easily – but we’d use those if we could!

3) Seal wood garden beds (with non-toxic sealer)

Sealing wood garden beds can help extend their lifespan many years beyond unsealed wood. Applying a sealer will protect the wood from moisture intrusion, mold, and decay. However, you don’t want to use just any wood sealer on your garden beds! Many sealants and stains contain toxic chemicals – stuff you don’t want around your healthy homegrown food and soil.

We recently used this nontoxic wood sealer on our new redwood garden beds. If you know me, then you know I do my homework before choosing materials to use in our home and garden! This particular product is food-safe, made in the US, won’t leach, has no VOCs, carcinogens or endocrine-disrupting compounds, and is nontoxic to wildlife. Plus, it gets great reviews!

We ended up applying 3 coats of Garden Seal to the inside of our beds (where rot is most likely to occur) and had enough left over to do just one coat on the exterior. It goes on milky white, soaks into the wood well, and dries clear with a slightly satin finish. However, the third coat inside the beds did leave a bit of a visible residue, so one or two coats for the exterior would be best. Be sure your wood is totally dry before application.

Hope’s Natural Tung oil is another nontoxic option to seal garden beds, though I’ve heard it’s best to reapply it annually – which is why we chose the other sealer. This would be a good option to seal the exterior of garden beds where routine application is possible. 

A 5 gallon bucket of Garden-Seal sits inside a raised bed. A paint roller is upside down, leaning against the bucket.
The nontoxic wood sealer we used on our new raised beds. We got a 5-gallon bucket since we were sealing 16 4×8′ beds (plus a few smaller ones). After applying three coats to the interior only, we went through about 3/4 of the bucket. So, the smaller one-gallon option would cover most home garden projects.
DeannaCat is using a paint roller to apply the sealant to the inside of the garden beds.
Applying the sealer with a paint roller. If you plan to seal both (all) sides of your wood, it is MUCH easier to seal the boards before assembling your raised beds. We didn’t decide to seal our beds until after they were already built (and only did the insides at first), so we applied the sealer to the already-assembled beds.
The inside of a garden bed is shown, half of the bed has had an application of sealant where the other side is still natural. The sealed side is slightly darker than the unsealed side. A paint tray and roller sit in the foreground with some milky colored sealant in the bottom. Seal beds to make garden beds last longer.
Unsealed redwood on the left, and after one coat of sealer on the right.
5 wood raised garden beds, full of plants and with gravel around them. In front of the beds sits a 5 gallon bucket of nontoxic wood sealer and a paint roller. Three of the beds are sealed and appear darker in color with the knots in the wood showing through more, where the two unsealed beds are lighter tan.
We were in a bit of rush to get our new beds filled and ready for spring, so we initially only sealed the insides. Then once things settled down, I went back and applied one coat of sealer to the outside of the beds too. You can see how much it makes the color and wood grain pop (sealed on the top/right, unsealed on the left).

4) Seal garden bed seams

In addition to sealing the wood itself, consider sealing the gaps between the boards. Again, wood garden beds are most prone to decay in their deepest nooks and crannies, including the corners and horizontal seams between the wood. When building our newest raised garden beds, we applied clear silicone to all the seams – which is waterproof, inert, and nontoxic once it dries. My friend Steve has been professionally installing and maintaining organic gardens for over 25 years, and he claims that this single step can extend the life of garden beds by 5 to 10 years!

We used a class 50 premium exterior silicone (or this similar option) to seal our garden beds along the inside seams only. Class 50 silicone is far more durable, flexible, and resistant to temperature swings than lower-rated classes. This is important since garden beds are exposed to varying temperatures, and the wood constantly swells and shrinks with moisture.

Use silicone to seal garden bed seams just like you would caulk. First, squeeze it deep, thick, and evenly into the cracks. Then while it is still wet, tuck your finger inside a paper towel and gently smooth it out – removing gaps, air bubbles, and excess. Pay special attention to sealing your corner supports! I also added a dab to any open knots, holes or cracks in the bed interior.

DeannaCat using a caulking gun with a  tube of silicone inside to add silicone to the seams of the raised beds.
Applying silicone to all the board seams with a caulking gun. For reference, I needed about one 10 oz tube of silicone to seal each garden bed measuring 4 x 8’ and 3 boards tall.
DeannaCat is using her finger and a piece of paper towel to smooth out the silicone that was applied to the seams to help against water intrusion.
Squeezed a good amount in there, and then smoothed it over with a paper towel/finger.
The corner of the inside of a raised bed is shown, the seams in between the 4x4 and 2x6 boards are sealed with sealant.
The final result. All sealed and waterproof!

5) Reduce wood-to-earth contact 

Clearly, your garden beds are going to be full of soil – so a certain amount of “wood-to-earth” contact is a given! Yet beyond their seams, wood garden beds are also quite susceptible to decaying along the bottom perimeter. There, they’re essentially sitting in constant moisture. So, another clever way to make garden beds last longer is to avoid setting the wood right on the ground. 

Our raised garden beds are perched on top of a couple inches of well-draining gravel. Because we have a nasty gopher problem, we also have hardware cloth and landscape fabric (permeable to water) below our beds. However, that isn’t to say you can’t have the bottom center area of your beds open to the native soil below if you prefer! I’m just talking about the wood itself. 

My pro garden friend Steve installs all his raised garden beds on top of a gravel border, similar to a french drain. To do so, he digs a small trench (about 6 inches wide and deep) and fills it with fast-drying ¾” leach rock. Then the perimeter of the wood garden bed frame sits on top.

Three redwood garden planters lined up one after the next with pathways between. They are sitting atop gravel which will help with drainage to wick away moisture.
Our raised beds are set on top of gravel, with hardware cloth in the middle to block gophers. Yet you could leave the middle of your raised bed open to the native soil below and only create a “tunnel” of gravel around the perimeter for the wood to rest on.

6) Shou Sugi Ban garden beds

Shou Sugi Ban is a Japanese wood preservation technique that involves burning or charring wood surfaces. The charring process essentially seals the wood, making the wood more resistant to water and insect damage. Shou Sugi Ban garden beds should last several years longer (or more) than untreated wood of the same species. 

To char wood garden beds Shou Sugi Ban style, most folks use a blow torch or propane weed torch. We’ve never done this ourselves, but I’ve heard one drawback is that it does take a lot of fuel and effort. Experts also say it’s important to not burn it too heavily, since deep burns can actually make the wood more susceptible to decay and reduce structural integrity.

This article explains more of the process. This YouTuber also shows his Shou Sugi Ban raised beds here – along with an update showing the inside of his bed 1.5 years after use.

Three wood garden planters sitting on top of bare dirt. The insides and bottom of the planters have be slightly burnt using the Shou Sugi Ban method.
Just as we chose to seal only the inside of our new raised garden beds, this person applied the Shou Sugi Ban method to only the inside and bottom perimeter of their beds – the most vulnerable places. Image via Reddit.

7) Promote good drainage

Good drainage is key when growing in raised beds. Plants prefer fluffy, moist, well-draining soil with plenty of air pockets for exploring roots and beneficial microbes. They don’t like soggy, heavy, compact soil – and neither does your wood! Heavy soils that hold in too much moisture can increase the likelihood of wood decay. On the other hand, raised beds tend to dry out more quickly than in-ground gardens. It can be tricky to achieve the perfect balance! 

Fill raised garden beds with soil that is made for containers or raised planter boxes. This article discusses how we create our own soil blend with bulk soil, compost, and an “aeration” component. Aeration additives include perlite, pumice, sand, peat moss, coco coir, rice hulls, or our favorite: ⅜” lava rock. It promotes that ideal blend of moisture retention and good drainage.

Furthermore, never seal off the bottom of your raised beds with impermeable material, such as a plastic lining. You want your beds to drain freely! I also do not recommend lining the wood walls with landscape fabric, even “permeable” and breathable ones. The fabric will hold in extra moisture right against the wood.

Elevated garden beds or those installed on top of hard surfaces (e.g on a patio, driveway or deck) should have plenty of drainage holes in the bottom – just like pots. For instance, we drill at least half a dozen ½” to ¾” holes in the bottom of our wood wine barrel planters.

Aaron and Deanna taking a selfie standing in front of their new garden area that is in the process of being created.
Our newest garden beds – all sealed, siliconed, and being filled with fluffy, rich, well-draining soil. These babies should last well over 20 years… hopefully 30+!

And that is how to make wood raised garden beds last as long as possible!

All in all, raised garden beds are a fantastic way to grow food, flowers, herbs and more. I love their sleek look, and for us, the ability to block gophers from getting inside. I hope you picked up a few new tips to help extend the life of your beautiful raised beds today. If you found this information to be valuable, please spread the love by pinning or sharing this post. We wish you the best of luck in building and preparing your beds – with years of bountiful harvests to come!

You may also like:

DeannaCat signature, keep on growing


    • Aaron (Mr. DeannaCat)

      Hi Heidi, we didn’t sand the wood before applying the sealer and it went on really well so I don’t think it is necessary. Good luck!

      • Heidi

        Awesome. Thanks, Aaron. And many thanks to all that you and Deanna teach and share with us all. It’s such a gift. 🙂

  • Nicola

    WOW, These are gorgeous; thanks for the inspiration. You hjave created some amazing gardens. Our school is starting a school garden. We have only asphalt (no patch of soil at all!!!) on which the beds will sit. I’m trying to find the best way to line the garden boxes (7′ x 2′). One option is woven weed barrier (which appears to be plastic). I’m considering burlap which is more natural. Any thoughts on if this will prevent anything from the asphalt leaching into the soil? I’m less worries about soil leaching out, more concerned about things from the asphalt leaching into the soil and plants for our elementary school students. Thanks,

  • Judy

    I just love reading your articles and watching your stories on instagram. You have a beautiful garden and home!.
    We have a 9×9 ground level vegetable garden bed and we normally just amend it each year by adding some sheep manure and a bit of peat moss, however its never as fertile and plants just do ok. I am wondering if the soil mixture you list in this article would be suitable for ours. I really want to remove at least 24″+ of the soil and give it a new overhaul. (btw we are in Ontario, Canada) Thx!

    • Aaron (Mr. DeannaCat)

      Hello Judy, if you have landscape supply companies in your area that offer quality bulk soil, that would be the way to go. From there you could add around 20-25% (to total volume of soil) of quality compost to the soil mixture and there may be companies in your area that offer quality bulk compost for delivery as well. If you wanted to stick with your peat moss regiment, you could add equal parts peat moss, compost, and and aeration additive like pumice, coarse vermiculite, perlite, or 3/8 inch lava rock to create your own soil mix. Sheep manure is a good additive on its own but it would be even better and more complete if it is left to compost with dry leaves, hay, or straw to create an even carbon (leaves) to nitrogen (manure) ratio. Hope that helps and reach out if you have any further questions, good luck!

      • Judy

        Thanks for the quick reply! I forgot to say that the sheep manure we use is the composted one sold in bags. I think this year we’ll finally try organic mushroom compost sold by the yard. And will definitely add in the lava rock you have recommended. I think the aeration portion is what we were missing. Thx again 🙂

  • Heather

    My loving and well-intentioned husband built me a large raised bed out of corrugated sheet metal, but for the inner corners he used lengths of pine only around 1.5 x 2.5. The beds are two feet tall. I’m not sure how these are going to hold up. Would you recommend I ask him to do it over? That will not make him happy!

    • Aaron (Mr. DeannaCat)

      Hi Heather, that was nice of your husband to build you a raised bed. I can’t say for sure if he would need to redo the bed as I am not aware of the entire construction of the bed itself. You can always reinforce the raised bed in time if the corners start to deteriorate, even by adding extra bracing or corner pieces on the outside of the bed. I would just use the raised bed and hopefully if will last you some time and if you need to do something in the future it will be at least a number of years out. Good luck and enjoy your new raised bed!

  • Caitlyn

    We plan to use Shou Sugi Ban and burn the inside and outside of our cedar garden beds. Is it with it to also seal and caulk, or is jut added effort for not much return? We want to have the beds last as long as possible.

    Thanks so much for all your great content! It’s been so helpful in planning my garden.

    • Aaron (Mr. DeannaCat)

      Hi Caitlyn, we are planning on the sealer and caulk help our raised beds last for quite a long time, longer than if we didn’t use them at all. We think it is going to be well worth the effort. Good luck on your raised beds and let us know how the Shou Sugi Ban method works out.

  • Rachael

    Thanks so much for this very helpful article. We just built four 4×8 boxes, with one gallon of the recommended sealer I was able to do two heavy coats of the boxes inside and out. I’d never thought about using silicone to seal the cracks, what a great idea. I finished the project today, I am confident these boxes will last for a lot longer than they would have. These tips are helping us get our money worth our of wood that is so expensive now. Thanks again.

    • Aaron (Mr. DeannaCat)

      Hi Rachael, glad to hear you were able to build your garden beds and take the extra effort to ensure they will last as long as possible. We are anticipating our raised beds to last for quite some time and I am sure your’s will as well! Have fun filling your raised beds with soil and hopefully you will have tender seedlings growing soon!

  • Tara

    Love this info, but I’m wondering how hard it is to keep the gravel paths and the outside edges of the beds weed free… do you have to use tons of weed killer? We’ve built the beds and the trellis supports and that all looks fantastic, but the weeds are awful. Your paths look AMAZING!!

  • Michelle

    Thanks for all the great info! I’d never considered caulking the cracks. Fantastic!
    I’d love a little info/advice on replacing boards on existing beds and repairing them. I’ve got some termite eaten beds that need repair and am just imagining that it’s not gonna be fun.

    • Aaron (Mr. DeannaCat)

      Hello Michelle, I guess it depends on what boards need replacing? If your 4×4’s or whatever you used for supports are in good shape, you can either pull the soil away from the side of the bed that needs replacing with a shovel until no soil is touching the bed. From there, if you used a drill to screw the boards on, just unscrew them from the corners and remove the deteriorated board and replace it with a new one. You may possibly be able to slide cardboard or thin plywood in between the soil and side of the bed if you didn’t want to remove some soil, hopefully creating a barrier between the soil and the boards you want to remove. Also, depending on your space and how many raised beds you have, it may just be easier to fully replace the raised bed with a new one. Granted you will have to remove a fair amount of soil which may or may not be possible, we have had to do this once and while it wasn’t fun, we were able to do it fairly easily. I may be able to offer more advice if I knew how the beds were constructed and what parts of the beds are in most need of repair. Hope that helps and good luck!

  • Lisa

    The new beds look so beautiful. What do you guys recommend for on-going/future maintenance, of the exteriors? Love seeing how you guys are building out your new home 🙂

    • Aaron (Mr. DeannaCat)

      Hello Lisa, we will just let the outside age naturally as we enjoy the look of the beds as they age. We could have used the same sealer we used on the inside of the bed on the outside but we opted not to. Other sealers, like the tung oil linked in the article should be applied every year or so for best results which is a bit more work than we want to take on. Hope that helps and thank you for the kind words!

  • Lori

    Thank you for so much great info on the raised garden beds, we are in the process of building our right now out of cedar. This article couldn’t have been more perfect! Thank you again.

Leave a Reply

Your email address will not be published. Required fields are marked *