Building a Raised Bed

Hi!  I'm looking to start a small vegetable garden in my apartment's yard, and I'm wondering if anyone has input on building the raised bed (I'm also very new to this website but I saw a lot of good advice!).  It's only going to be 4x4ft (12 inches tall), so I'm hoping it will be alright to use 1-inch thick boards because I'm on a bit of a budget, and 4x4x12in doesn't seem like it would be too much soil weight on the sides.

My main question is if it would be better to attach the boards to each other at the corner (every-other, as in figure A) or to a post (as in figure B).  (For clarification, the bed would be three planks tall either way, I just didn't want to draw all three levels of planks in MS Paint).

The post seems sturdier, but I've heard that because the soil is pushing outwards, it's essentially pulling out the nails slowly because the nails are attached in the same direction as the soil pushes.  Whereas I think varying the boards as in figure A would mean that the soil doesn't pull on the nails the same way due to the varying directions, although I'm really not sure.  If anyone has insight on this (or how big of a post to use for figure B), that would be amazing!

I'm also not sure on wood type.  Cedar wood is a bit expensive for me at the moment, and I'm not even sure how long I'll be staying in my current apartment to keep this bed, so it's alright if it's temporary as long as it doesn't really affect my actual plants.  I'm looking between knotty pine wood and what the store calls SPF (spruce/pine/fir) wood.  I know everyone recommends pine as the budget wood option for garden beds, but I can't tell if that applies to SPF wood.  There is somewhat of a price difference (it would probably cost around $65 to build it with the knotty pine and around $30 with the SPF), but if SPF is really that much of a problem then I can definitely opt for the pine, it's far more reasonable to me than buying cedar at this point in my life.

Also, is it important to cover the insides of the wood with some sort of liner to stop soil from seeping in, or does it not really matter?

Thank you for reading and (in advance) for the help!

Hi R,

To build the longest lasting raised beds, the corners are the most important in my experience. At this very moment our second set of raised beds is collapsing. Most of the boards are still fine, but again, the poles are rotting faster, probably due to their vertical orientation, which favors wicking water from the ground as well as absorbing rainwater when it lands on the top.

We choose the hardiest quality wood for both the poles and the boards, and it lasted quite some time (10+ years). What we wish we had done, is using steel 90 degrees angled profiles in stead of poles, on the outside corners of the beds. We should have driven them half the length into the ground. We even considered doing that when the wooden poles started to give up two years ago. We could imagine that even when the boards would rot away, we could replace them by sliding (hammering) in new boards from above.

We decided not to do that (because we have so many beds, that it would be very expensive; we have "funny" shaped beds for which no standard profiles are available and our ground is pretty soft, what probably would cause the steel profile to loose its exact vertical position relatively quickly so it can no longer function. We decided to go "all natural" and let all beds collapse into hills, which we are connecting with each other hugelstyle), but we still think that the steel poles are a good idea!

Good luck with your bed, have fun building and growing!

If you will have 12" tall beds and you say it will be 3 planks tall, then the boards you are proposing must be 1x4. Where I live, I can get 2x for about the same price as 1x. If you use 2x6, the bed will only be 2 boards high.

Where I live, a 2x6x8 is $6. For a 4'x4'x12" bed, you'd need 4 of them. I do not use any type of liners in mine and the soil stays in just fine. If you use untreated wood, you may want to paint the boards before assembly so they last a little longer.

Either way, you will essentially have 2 or 3 stacked box frames. You must have a way to secure each individual box frame to the others to keep them in line vertically. That is where the corner posts come in. They could be a piece of 2x6 as well or 4x4 or even a round piece of wood. The corner posts keep all of the boxes aligned vertically.

I like to have mine like your figure A, horizontal boards overlap and attached to each other and also have the vertical corner board as in figure b with a couple of fasteners.

I created a bunch of wood sided raised beds for my garden and I'm on around year four or five with them. I utilized 2x12 rough cut pine where I affixed the screws through the boards similar to your option A.

I have just started to see some breakdown of the connections (Wood wearing where the screws are holding) but the beds are still holding together. I use mulch in the pathways between the beds and found that the mulch itself has helped keep the boards anchored in place.

We use raised bed using the option B.

I feel either way will work.

Option A might be the best as it requires more nails or screws.

To me what goes into the raised bed is most important.

The bottom layer could be leaves, sticks, twigs.

Then a layer of 1/3 compost and 2/3 quality top soil.

Some folks add vermiculite or perlite for aeration.

Top it all off with a layer of compost.

Our raised beds also contained well rotted manure and leaf mold mixed with the 1/3 compost and 2/3 top soil though this is just an added bonus.

Jackson Bradley wrote:If you will have 12" tall beds and you say it will be 3 planks tall, then the boards you are proposing must be 1x4. Where I live, I can get 2x for about the same price as 1x. If you use 2x6, the bed will only be 2 boards high.

Where I live, a 2x6x8 is $6. For a 4'x4'x12" bed, you'd need 4 of them.

What wood type are you using that a 2"x6"x8' is $6?  For me, that sounds close to the price of the generic SPF (spruce/pine/fir) wood I mentioned above.  This is part of why I was trying to figure out if using "SPF" (unnamed spruce/pine/fir) wood would work okay, or if I need to actually use wood labeled as pine.  Where I am, a 1"x4"x8' is about $9, and a 2"x4"x8' is about $20 for actual knotty pine wood.  That's why I was going for the 1x4's. (especially considering its small size, and that I may not stay in this apartment for that many more years anyway).

If I were to use the "SPF" wood, I could definitely use 2x4's, as those are $4 each.  I'm just not sure what that would entail for gardening or if it's recommended.

Thank you so much for the information!

R Cohen wrote:

Jackson Bradley wrote:If you will have 12" tall beds and you say it will be 3 planks tall, then the boards you are proposing must be 1x4. Where I live, I can get 2x for about the same price as 1x. If you use 2x6, the bed will only be 2 boards high.

Where I live, a 2x6x8 is $6. For a 4'x4'x12" bed, you'd need 4 of them.

What wood type are you using that a 2"x6"x8' is $6?  For me, that sounds close to the price of the generic SPF (spruce/pine/fir) wood I mentioned above.  This is part of why I was trying to figure out if using "SPF" (unnamed spruce/pine/fir) wood would work okay, or if I need to actually use wood labeled as pine.  Where I am, a 1"x4"x8' is about $9, and a 2"x4"x8' is about $20 for actual knotty pine wood.  That's why I was going for the 1x4's. (especially considering its small size, and that I may not stay in this apartment for that many more years anyway).

If I were to use the "SPF" wood, I could definitely use 2x4's, as those are $4 each.  I'm just not sure what that would entail for gardening or if it's recommended.

Thank you so much for the information!

It is from the local bog box store. If you use untreated, you could paint it before building to extend the life. Treated would last longer but you'll have to decide if you want that wood contacting the soil you are growing plants in. I do not think there would be much of a difference between spruce/pine/fir or #2 pine but others may be able to chime in on their experience.

How long the wood lasts would be very specific to your environment. How wet, humid, termites, etc.

I think the ideal material, if the goal is longevity, would be concrete blocks or bricks. With the concrete blocks, you could fill some of the cells with bag mix concrete and rebar driven into the ground.

I have made lots of raised beds. Mostly out of pallet wood, because I'm on a strict budget. I have used both methods you showed, and both work.
Cedar fence pickets are pretty affordable, and will hold up pretty well. I prefer screws to nails. On trick is to sink your nails, or screws at an angle to help keep them in place with the soil pressure. Personally I would reduce the width of the bed to 3 feet wide and make it a little deeper, if possible. Veggie like tomatoes like a little deeper than 12". If it won't work for you, you can always get a 5 gallon food grade bucket, or inexpensive nursery pot and plant veggies that need more room in them.
Good luck, what ever you decide, Enjoy the process.

I have a thought for option C

Basically go with option A, but put a little 90 degree angle iron around the outside.  That angle iron will make the connection stronger than either option A or B alone.  If you really want to go crazy, instead of using a wood screw, use a short bolt.  A bolt with a proper washer and maybe a nylox nut (to prevent loosening over time) will remain very sturdy for the life of the bed and the total cost should not be very high.


My two cents,


Eric

Screws at an angle like Jen mentioned is a good shout. The other thing worth doing is putting a couple of cardboard layers at the bottom before you fill it, kills the grass underneath and the worms love it. Breaks down within a season anyway so it's not permanent.