Raised bed materials

Hello everyone,

I was hoping to get some perspectives on raised bed materials.

I started making raised beds about a decade ago when I cleared my woods of debris left from storm damage.  At the time I hauled out a lot (20+) tree trunks from downed trees in our woods.  I had them laying all over the yard (I had not heard of hugel beds yet or I might well have used them in that application) and I needed to do something with them.  Instead of burning them I decided to use them for the edges of raised beds.  The trunks were typically about 12” in diameter and I thought this was a much better use than burning.  And they have served well but their usefulness is at an end.  They are rapidly rotting out and even collapsing under their own weight.

Some of these logs have already been completely replaced, the remnants of the logs buried in the bed as a sort of sunken hugel bed.  They were replaced by 2x10 lumber painted with drylock for rot protection.  These edges are working well and 2 of my 3 beds have been converted this way.

But the last bed is a bit different.  It is 32x6 feet.  The cost of 2x10 lumber was adding up for the other beds, especially considering the added drylock.  For those beds, 16x8 lumber was just fine.  But I am hoping to do something more affordable for the 32x6’ bed.  I was thinking about using cinder blocks as they are actually slightly cheaper than 2x10 lumber and require no prep work.  Further, I doubt I can just drop 32’ of lumber on the ground and expect it to be flat—the ground undulates too much.  

So cinder blocks are one option, but can anyone think of other options?  I am not thrilled by the aesthetics of cinder blocks just sitting out, so I am open to other options.

Thanks in advance,

Eric

Hi Eric. I don't have suggestions for other materials. I just wanted to say that if you do decide to go the cinder block route, you could always just own it and paint them crazy colors. If you have kids, let them paint designs all over them. Then it's an "art project" rather than a cheap way to make a raised bed.

Cinderblocks are not that bad, because you can plant in them, and the plants can tumble over the edge and they don't show much.  They can also be painted.  They can be rearranged if you change your mind, and you will have them forever, you can take them with you.   You'll never have to replace them.

I started out with wooden raised beds and they got termites, which then got into the house.  A serious, expensive lesson!

If you change your mind, there are dozens of uses for cinderblocks.  I've grown strawberries in them, built retaining walls, held down tarps in a storm, made patio furniture (chairs and tables), and stacked them so they hold pipes, lumber, long things.

I had a ton of cinder blocks from demolition projects and old retaining walls, and I used them to build terraced grow beds. Some I capped with Allen blocks (came with the property) but others I just capped with weathered spruce boards. They really don't look bad. In fact, with the plants taking over the beds, I hardly notice them at all.

Everyone,

Thanks for the feedback! I am glad that everyone seems to like the idea of cinder blocks.  I have thought about staining them brown just to vaguely resemble wood.  Also I have considered planting into the hollow parts of the blocks with pollinators or something similar—it just seems like a waste to not use them.

Eric

Hi Eric

To use a different path... why 32 feet? Why not four 8 foot beds? This should help to to get back to using logs as the cheaper material.

John,

Actually you make a really good point.  The short version is that I am out of logs.  These were plentiful a decade ago and I decided to use them knowing that eventually they would rot away.  Also, as my beds are filled with wine cap inoculated wood chips, the wine caps are aggressively attacking the log remnants.  I have places where the 12" diameter logs have been reduced to a pile 2" tall.  In other places, the "logs" are really just a shell of a formal log with a few pieces of wood that for whatever reason have not rotted away yet, but I know that they will.  Out of the 20+ logs I had a decade ago, only a small number remain and they are in bad shape--there are no replacement logs

You make a fair point, but I am just out of logs by now.

Eric

I was gonna say logs too. :)   So you don't have them.  What do you have? Rocks? wine bottles? red clay?

The simplest raised bed I have seen is someone shoveled out a foot deep or red clay then used that to make the sides of the raised beds.  Filled that with topsoil and compost.

I think the blocks are a great idea.
I have three beds like that all with at least 2 courses of block.
I tend to level and tamp the earth under the first course, drive stakes through the holes and fill them with rocks and gravel.
This keeps them in place rather well.

Be certain to look at Craigslist for free or cheap block.
I have rarely bought these blocks from the store, but they are generally the best value in cementous blocks.

I think a good case has been made for cinder blocks. Just to add another option, search up "ferocement". There was a recent thread on here with some beautiful examples of raised beds with a lovely aesthetic. Not  sure about the economics though

My mom has two cinderblock raised beds and the only drawback is that sometimes the plants in the holes dry out and fry in the sun. Otherwise it has been a success. Now if I can just convince her not to turn those leaves under every spring.

Natural wood from your local hardware store may last about 5 years, so cement blocks might be the option.

I built mine out of cob. The cost was zero dollars, the time was 3 months.
They do an amazing job... I filled them with rotted wood, branches, chips, leaves, compost and soil. The thermal mass warms up before the ground and stays warm through the night. After the seedlings are tall enough, a good deep watering and mulching, there is very little need to water again.

Chris Sturgeon wrote:I built mine out of cob. The cost was zero dollars, the time was 3 months.
They do an amazing job... I filled them with rotted wood, branches, chips, leaves, compost and soil. The thermal mass warms up before the ground and stays warm through the night. After the seedlings are tall enough, a good deep watering and mulching, there is very little need to water again.

Yes!  I was just about to make some earthbag raised beds.  Can't believe I forgot to mention that.

Chris, Rob,

Thanks for the cob suggestions.

Truth is I have the ingredients for cob on hand.  My soil is brick hard clay anyways.  However, when I do this, it needs to be done fairly quickly.  My other raised bed projects, especially the fence for the raised bed, got long and laborious enough that eventually the project slowed to a halt and took about a year to finish.

The more I think about it, the more I am liking the idea of just getting some cinder blocks delivered and plopping them in place and being done with things.

I will give one big shout out for cob though and that is the energy (or lack of) needed for production.  I did my masters degree in history and largely focused on the history of energy.  I see an energy component to absolutely everything. From paper to cars, planes and other vehicles.  I see energy in my coffee in the morning (might be surprised how much that is BTW).  The energy for cob is basically limited to my meals consumed to do the labor (still more than one might think.  Muscles are only about 25% efficient).  But cement production is one of the most energy intensive operations on earth.  Despite their apparent simplicity, cement takes some serious energy just for the actual making of cement powder, leaving out transportation and mining for basic resources.

Nonetheless, cinder are probably most attractive, even though cob has a lot going for it as well.

Eric

Eric.
"Time vs. money vs. embodied energy" is pretty much the trinity that informs my decisions in life. There is always a push and pull between these factors, but sometimes an amazing synergy!

As a side note, I'm trying to get a local oyster bar on side so I can collect shells and burn quicklime for my own projects. I don't know if this is any less energy intensive than commercial concrete, but at least it saves the transportation to my remote northern location. Plus, another factor, I get to learn a new set of skills!