13 Plant-Safe Wood Sealers For Planter Boxes

When it comes to constructing planter boxes, there are the obvious things to consider, and the things that might slip your mind. Unfortunately, it's the things that may slip your mind that can have a harmful effect on your plants.

A perfect example of one of those things is the chemicals that are used when it comes to treating and sealing the wood you use in the construction of the boxes themselves. Whether the wood was pre-treated before you bought it, or treated by you after the purchase, knowing if the chemicals used to seal the wood can be harmful to your plants is important.

But you're using the chemicals to treat the wood, you think, not pouring it into the dirt. Why does it matter?

Unless you have some kind of neutral, physical barrier like a sheet of plastic between the dirt and the wood, the chemicals used in the treatment of the wood will inevitably seep into the soil.

If the chemicals you use for the treatments or sealing of wood are toxic or hazardous, they will harm your plants. As you water the plants, those chemicals will bleed from the wood into the dirt, and your plants will mistake them for food poisoning themselves. But have no fear, these catastrophic events can be prevented by using a plant-friendly wood treatment.

Plant safe wood sealers are generally derived from plant-based or other natural and organic materials, and won't harm your plants if or when they seep into the soil. What does this mean for you? You get to help your wooden planter boxes last longer, and you get to do it in a way that won't end up poisoning your plants.

Finding natural, plant safe wood sealers may seem more easily said than done, but we've already done all the work for you! Let's go over some of the best, plant-safe wood sealers for your garden boxes, and hopefully, you will find one you like.

Satisfy yourself with these types of planters and planting pots.

1. Raw Linseed Oil

Linseeds in spoon and bowl with glass of linseed oil on wooden table

Raw linseed oil, derived from the flax plant, is a perfect, natural alternative when it comes to wood treatment if you're trying to avoid chemical sealants that could end up harming your plants.

Applying this linseed oil to untreated wood will increase its water-repellant properties, and help weatherproof it. Once you apply it, you're going to need to let it dry for two to four days to allow the oil to completely and fully penetrate the wood.

Click here to check out this product on Amazon.

2. Real Milk Paint PTO-G Pure Tung Oil

Pure Tung Oil with no additive or preservatives is what you get from this offering by Real Milk Paint.  This plant-based oil will bring out the beauty in your wood while enhancing its water resistance.

It is all-natural oil pressed from the nut of the Chinese Tung tree and is safe for use on any porous surface that needs preserving. It is environmentally friendly and food-safe.

Click here to find this on Amazon.

3. Hope's 100% Tung Oil

Hope's 100% tung oil is another great environmentally safe choice to seal your wood garden planters beautifully. Hand rub several coats in to bring out the luster and grain pattern in your wood. While it will not be as shiny as varnish, tung oil will dry to a hard finish.

Click here to find this on Amazon.

4. Tung Oil

Tung Oil is the substance produced from pressing nuts grown from the tung tree. Tung Oil, also called China Wood Oil, is a completely natural way to treat your wood products, like garden boxes, and it comes with a few nice aesthetic perks!

Tung oil, especially when it's applied in several coatings, can give the wood you put it on a sort of wet, satiny look that is quite pleasing. In comparison to other oils, it also has a fairly quick drying time, which makes it nice if you're short on time or patience.

Click here to check out this product on Amazon.

5. Eco Wood Treatment

Unlike the other options we've mentioned so far, this product ships as a powder, not a liquid. This not only makes it slightly cheaper than some of your other options, but it takes up much, much less space to store it if you don't end up using it all.

Extremely easy to use, you just add water and go! Even if there is a leftover surplus that drips onto your grass or into the dirt of the garden box, the residue isn't harmful, so you don't have to worry about it killing your grass or other plants.

Click here to buy this sealant from Amazon.

6. Lifetime Wood Treatment

If looking for a wood treatment that can come in contact with you, your plants, and your animals without having a harmful impact on them has become exhausting, look no further! Lifetime wood treatment is a natural, non-toxic option that is backed by independent lab testing and over 60 years of use by professional craftsmen.

Shipping a gallon's worth at a time, this is a treatment you should try for yourself!

To buy this product from Amazon, click here.

7. Seal-Once Nano+Poly Wood Sealer

Make use of advanced nanotechnology in a polyurethane sealer to protect your wooden outdoor planters for up to ten years! This sealer goes on fast, with a wet on damp application. It is ultra-low VOC, which means it is safe for your pets and your plants.

With eleven different colors available, plus clear, the hardest decision you will have is choosing which one you want!

Click here to find this on Amazon.

8. Ecoprocote Eco-Poly Finish & Sealer

Need to finish your wood and concrete planters? This water-based urethane works great for both types of surfaces, and thanks to its advanced plant-based urethane technology and bio-emulsion resins it is low odor and highly durable.

At least two coats will result in a beautiful glossy shine that will enhance garden decor!

Click here to find this on Amazon.

9. EcoProcote

A soy-based product, you don't have to worry about accidentally killing your plants when it comes to this sealant. Odorless, non-toxic, and fast-drying, you have nothing to worry about when it comes to this chemical and possible exposure to your plants.

Even better, it's UV resistant, which can help prevent the wood from turning grey due to sun exposure.

Click here to purchase this product from Amazon.

10. Seal It Green

Plant-based, non-toxic, and made specifically for planter boxes, this product is safe for your plants. It helps protect the wood against sun damage, water damage, and warping, and cracking.

And to top it all off, each application of the sealant to the wood lasts for over a decade, making it a very low maintenance product. Water will roll right off the wood after an application or two of this product, so give it a try!

Click here to view this product on Amazon.

11. Eco Advance

Where some sealants need several days before they're dry, and the wood is "safe" for use, Eco Advance dries in less than two hours, effectively making it one of the quickest drying options we've found.

It can also be used in a sprayer, which means you don't have to be down on your hands and knees with a brush to apply it.

It's completely safe for you, your kids, pets, and plants, making it quick to dry, quick to apply, and non-toxic. All in all, the perfect combination! And with a low odor, you're not going to walk away with a chemically induced headache by the time you're done applying it.

Click here to buy this sealant from Amazon.

12. Garden Seal

This sealant is non-toxic, eco-friendly, and contains no VOCs. Lather it on all of your wooden beds for a nice clear protectant. It's also UV-resistant, so your wood will stay looking nice for an extended period of time. Your plants will thank you for using this sealant.

Click here to purchase this product from Amazon.

13. Seal-Once

This specific sealer has been formulated to protect wood that gets exposed to lots of water, even the marine life that can come with increased exposure to the ocean. It can easily handle the frequent watering that even the most thirsty plants require!

Preventing all kinds of mold and algae growth that increased exposure to water can cause, rotting, warping, cracking, and other damage, this is a fantastic sealer to use, and yes, it's safe for your plants, pets, and you!

Click here to buy this product from Amazon.

We hope you found this list interesting! Here are a couple of related articles -

10 Awesome Balcony Garden Containers for Your Plants

21 Box Garden Ideas [Picture Inspiration]

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A collage of plant-safe wood sealers for planter boxes available on Amazon, 13 Plant-Safe Wood Sealers For Planter Boxes

One comment

  1. Question – we painted and put polyurethane finish on two window boxes last year, and for the first time in over 20 years, my flowers struggled to grow – really did not grow, even after replacing the soil mid-late summer. Should I sand the polyurethane off? I believe it was water-based (not positive). Any other advice? Thank you.

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