Repeat - do not use railroad ties for raised beds because they were heavily treated to resist rot. There was quite a controversy some years ago about pressure-treated lumber because it was typically CCA-type (the preservative included an arsenate compound that either did or didn’t leach into soil significantly, depending on who you believed). Today’s pressure-treated lumber is entirely based on a copper preservative that is widely deemed safe for vegetable crops.
I’ve had a couple of large raised beds for at least the past 8 years that are of recycled plastic and have lasted well. They have about a foot of soil raised over grade. I mixed in cheap topsoil, compost, rotted manure and whatever else was handy. One bed currently is for blueberries and the other has mostly been for strawberries (this year I planted potatoes in it). Something to remember about raised beds is that they will dry out faster (they also warm up and lose sogginess from winter conditions faster than surrounding ground, which is an advantage). In summer you need to keep an eye on them to avoid crops drying out during long stretches of hot dry weather.
If you go with wood, home improvement places like Lowe’s will make straight saw cuts for you, which makes setup a lot easier.
I’ve seen those metal corner supports in gardening catalogs. That much dirt gets very heavy when its wet. Those supports keeps the corners from busting open.
I see the OP is from around Chicago, so this might or might not work, but perhaps others can benefit. It doesn’t get below freezing very often in western Oregon, but we do get a boatload of rain in the winter. To keep soil from washing out of the planter and to magnify whatever sun we do get, I make bed covers using 1/2" PVC and some conduit straps for a frame, and some heavy mil plastic (not black) as a cover. Something similar to this. Drape the plastic over it and tie the ends shut so the wind doesn’t take it.
We cover the herb beds in late fall, and when we remove them in the spring we have a good crop of oregano, chives, parsley, thyme and mint that survive the winter without a problem. During the winter, just lift up the plastic to cut what you need.
One thing about the PVC. You want to bend it on a relatively warm day, as cold+plastic=broken PVC. Just secure one end with a strap and slowly bend it until it reaches the strap on the other side.
Another suggestion: if you are planting annuals or veggies that go away by summer’s end, plant a cover crop in the beds for the winter. It adds needed nutrients back into the soil and can just be turned under in the spring. Any nursery will have cover crop seed.
So our downstairs neighbor (the one in the garden unit) sent around an e-mail this morning to the effect that we may need to do some really major plumbing work affecting the whole building, which would involve digging up the entire front yard. (We apparently have a major case of tree roots growing into the main water line.) His unit flooded badly once a couple of years ago, and he doesn’t want it to happen again – and I can’t say that I blame him. So all this may or may not be tabled until a decision on digging up the yard. But OTOH the two side beds might not be affected at all, so who knows?
FWIW, my wife and I just made 4x8 foot beds using two 2x6s (so 12" high). She used a beeswax and mineral oil preservative she found online (like this, but I’m not sure if that’s the exact recipe she used) on the lumber to avoid bad chemicals leeching.
Depending on how long you want to keep them, going to much effort to line or treat them might be overkill. I used 1x6 cedar with the bottoms buried an inch below grade, and after 8 years they have minor warping but no rot. This is in the rainy Pacific NW.
Next time I’ll use 2x6 boards to cut down on the warping, but I’m not convinced treating the wood with something like wax will extend its life much unless you are regularly reapplying it (which necessitates digging it out). A rot-resistant wood like cedar will last a good long while on its own.
MY $.02 – Do the math on how much soil you’d need to fill a raised bed, and cost it out. It would take a LOT of 5-pound bags from the garden store to fill even a small bed, so you’re probably looking at getting it delivered in bulk. At which point, if you’re OK with the cost, you have to start having contingency plans to deal with excess, because bulk deliveries of soil are not very precise. You’ll may calculate that you need exactly 4 3/4 (cubic) yards, but you’ll get somewhere between 4 1/2 and 5 1/2 if you’re lucky, and maybe even more. If you’ve got enough yard you can just spread out the extra dirt, that’s fine, but be aware of the possible issues.
That’s what my wife and I did too. They have worked very well for 5 years, but one of them needs replacing finally.
Oh… buy them at some point after it’s been dry and not rainy for a while. They do soak up water and weigh quite a bit more when wet! I found that out the hard way.
We got bulk garden soil as well- much cheaper, although we did have to invest in a wheelbarrow for it.
This. Keep it simple. I’m in MSP and this is what we use, plain old untreated pine construction lumber and we get about 10 years out of each box before we’ve had to replace. Replacing is actually pretty simple, lots easier that I thought. We’ve had our boxes (4 of them, 8’ x 4’) for almost 15 years having replaced each once.
Where I’m at, cedar is more than 5x the cost of untreated pine. We considered cedar, but the math worked out to be like 80 years (replacing the pine once every 8-10 years or something like that) before we would recoup the difference.
We didn’t use plastic, or paraffin, or weed barrier or anchors or anything. We just put them down right on the lawn where we wanted and filled with some pretty expensive garden center dirt - had 3 yards delivered.
For the corners, I used 3" deck screws (might have been 2.5" - either would work) and braced the inside with a 4x4 post cut to height. Last replacement, I had trouble finding an untreated 4x4 post, so I used two standard studs (2x4s) stuck together with construction adhesive (liquid nails).
Wife does a mix of veggies, herbs, and flowers in all four boxes and she gets great results. I’m just around for the heavy lifting.
Before building raised beds beside a driveway or sidewalk, think about where you put your snow in the winter. A raised bed will mean that you can’t just shovel it off the edge. You’ll either have to push it farther, or lift and throw it.
So I went to poke around for ideas today, and now I’m thinking of using something more like this. Would I be crazy? Is there anything I should know? I am thinking of amending the soil we already have with some additional topsoil, peat moss, compost, etc. But do you think I would be nuts to use stones to build a relatively shallow bed, without cementing them?
Your link is missing a colon, I think. I was able to tweak it to get to the page you meant.
I think those kinds of stones would be fine because the square edges will fit closely enough together to prevent dirt from spilling out… though I do notice they have rounded corners.
It will be important to make sure the ground is level so that they fit together well. Any gaps between them can permit dirt or water to come out, or allow weeds to start growing there.
Cheaper is plastic political lawn signs. And probably much more available in the Chicago area. You can probably get them free – ask a candidate who lost.