Flower Planters - Pressure Treated Plywood

Has anyone made flower planter boxes with plywood? Whats a good 4 season protectant? Or has anyone used pressure treated plywood? Stain for it as well?
Any guidance would be appreciated.
Thanks for your time.

The traditional material here would be cedar (or in some locales, locust) or redwood if you can get it — why would plywood or pressure treatment be necessary?


It doesnt need to be plywood. I was more curious if anyone had worked with it before and by chance for this application.

The adhesive in the plywood will fall apart fast. You probably won’t last one season. The chemicals used for pressure treating are by necessity very toxic (usually copper compounds which are biotoxic). I second the recommendation from Will. Also some people use metal Galvanized steel or copper.


Fully agree with you both. Thanks for the replies.

It wasn’t plywood, but I purchased hardwood from lowes advertised as “severe weather decking treated lumber”. It cut and stained like normal lumber. The flower boxes are starting their 3rd summer and seem to be holding up well.


I have always heard that white oak is weather and bug resistant like cedar but I could never bring myself to do an outdoor project in white oak.

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I have some beautiful red cedar. My property is full of.it. what an amazing looknit is!

Yes, White Oak.

Red oak is NOT as good for outdoor applications. It matters, so look close before buying.

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I made these above ground planters out of PT lumber for a local gardener. I used a Grey stain and then a UV protecting Marine finish to seal them.


Ditto everything said about not using plywood, but if you do, paint it rather than staining it. Nothing will protect wood better than a good exterior house paint.

There are a lot of new products for decking that are basically plastic and wood. It is guaranteed not to rot or chip and peel. Wood is a great product but eventually it will fall to pieces and will require maintenance like recoating and washing. So check out some of the newer deck materials that works like wood and would likely take paint if you cant get the colors you want. This is just an example.


Another option might be sheet PVC. PVC can be used as colored or can be painted your preferred color. However anything with paint eventually has to be repainted. The PVC will expand and contract and eventually the paint will peel and fail.

As others suggested cedar and redwood will last a good long time but everything eventually returns to the dust it came from. Treated pine will not last until the water gets hot. The current cooper based solutions for treated wood does not work well. The man made materials will last longer than cedar or redwood and is regular wooding tool friendly. White oak has been mentioned but that is quite expensive and is not readily available. In the big box stores they only have red oak. White oak is what sailing ships were built of. Red oak has the capillary straws that adsorb water and rot from the inside out. Plus red oak is cheaper than white oak but not by much. For more exotic wood there is Teak and Ipe but those are at another price level above white oak. Any wood outside will require maintenance of cleaning and painting/staining every couple of years.

Good advice here. Might mention also that acacia wood is a much more affordable alternative to something like teak. It holds up well outdoors, and is said to be more sustainable although I have only heard anecdotal claims of that.

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One option is not to put dirt in the planters, but instead put the plants in pots or windowbox liners and put these in the planters. In that case you could make them with anything as long as you paint or stain it. I have made several planters with cedar or PT fence pickets. They are cheap and easy to build. I have made raised beds with plywood (exterior treated with linseed oil) they only lasted a couple seasons. On the other hand my raised beds made with cedar boards lasted 10 years. I also have used the whiskey barrels they sell at the big box stores for flowers. I coat the inside and the bottom with a couple coats of used motor oil; the set in front of the house has lasted 10 years.

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Use marine grade plywood, its waterproof

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