How do I make my raised beds nicer?

September 26, 2022 4:07 PM

I have four old raised garden beds made out of wooden 4x4s. I never stained or sealed them or did anything to them (except garden in them). Now I want to pay some attention to them. Is it too late? What can I do?

They were put in maybe 4 or 5 years ago. I don’t know if they’re treated or untreated, but if that’s important information I can try to figure it out (how?). They’re definitely weather-worn but still intact and sturdy. I want to (1) make them look nicer and (2) help them last longer. Assume I know very little about what I’m doing, though I have stained furniture before. What can I do?

posted by southern_sky to Home & Garden (5 answers total)

Best answer: This is a perfect use application for a product called Eco Wood. It's non-toxic and mineralizes the wood to make it longer lasting. The "clear" will dry and age to a lovely silver gray; it's also sold as a stain in a limited range, or can be tinted with pretty much any water-based stain. Available at paint stores, Home Depot etc. Absolute cinch to mix (with water), apply and clean up; one application lasts for years.
posted by vers at 4:43 PM on September 26, 2022 [5 favorites]

Even if they're treated, i'm surprised they've lasted that many years. My climate is probably rainier than yours, and treated raised beds last like, three years tops before they start to lose some structure.

Especially if aesthetics are important, your time and money may better be spent not by trying to extend their life, but planing for their replacement with hardier buddies. Corrugated metal lined beds last much much much longer than wood (treated or not). If they really are not rotting or otherwise in decay, you could empty the soil out, and then line the insides with corrugated metal. Framing them like this takes less material, but if you already have structure there, you can just pop them down the sides, facing the soil.

Wood in contact with soil is food for plants, not a structure to contain plants (permanently).
posted by furnace.heart at 4:43 PM on September 26, 2022

It does matter if they're pressure treated for things like whether sanding is a good idea and what will adhere, take some close up photos and link them if you can. Or plug "pressure treated lumber" into google images to get a sense of the markings that leaves on the surface.
posted by snuffleupagus at 4:52 PM on September 26, 2022

If you have raised beds made from 4x4 wood boards, most likely they are pressure treated wood. Untreated hardwood like cedar or redwood 4x4 is hard to find, and very expensive. So most likely they are 4x4 pressure treated pine meant for home construction, decking, or fencing. If you are using them for ornamental gardening, no issues in continuing to use them until they start to rot away.

If, on the other hand, you use these for any vegetables or herbs, please replace them with untreated hardwood and use liners for longevity. The chemicals from pressure treated wood can and will leech into your veggies. These chemicals are quite harmful. Here is an article discussing some options for non-toxic raised beds:
https://thebackyardpros.com/best-non-toxic-wood-treatments-for-raised-garden-beds/
posted by thewildgreen at 5:12 PM on September 26, 2022 [4 favorites]

The old arsenic based compounds were a potential concern for edible gardens, as that link states the newer ones are less concerning (in terms of leeching into crops, versus 'ponds and aquatic life' and provided you're not concerned with 'organic' trade standards).

See also OSU Extension Q&A

But you don't want the newer stuff in your lungs, so it matters for sanding (especially power sanding), and if it's treated then that also limits what you can do to it now.
posted by snuffleupagus at 5:51 PM on September 26, 2022