By Cassie Johnston
Jump Directly to Project
Share this post:
As I mentioned in our Garden Plan post for this year, one of our huge undertakings for our 2018 vegetable garden is building brand new galvanized steel raised beds. This will be our sixth growing season working this space, and this year, we decided it was time to invest in our “forever” beds.
When we first started growing in this space, we had planned on growing in wide raised rows in our garden space like is suggested in one of our favorite gardening books—in fact, we even spent one fall digging them throughout our entire growing space—but it didn’t work out for us for a few reasons. The main issue was that we have a wicked weed seed infestion in our garden soil. We’ve tried fighting it with mulch and a lot of back-breaking weeding, but we ended up losing the battle every year. We decided something had to change—and building raised beds with fresh soil was it.
Of course, weed control isn’t the only benefit of raised beds. We’ve always had amazing success growing in raised beds because you have so much control over the growing environment—it’s easy to control the watering, the fertilizing, and the pests. They also look beautiful, and since we ended up making our raised beds so high, they make any garden work easy on the back and the knees.
There are some negatives to raised bed gardening though. The main one being that it dramatically reduces your growing space. You just can’t cultivate the same number of plants you would be able to if you took the same space and make wide rows.
The other big hiccup: it’s expensive to build raised beds. Tilling up a plot of land and planting some seeds is relatively cheap (or even free), but once you start adding in building materials to build raised beds and soil to fill them up—it can get pretty pricey.
So we considered the pros and cons of all methods of cultivating our garden, and in the end decided that nice, long-term raised beds were where we wanted to invest our gardening budget this year. Once we had decided that raised beds were the way to go, we had to do some decision making on what materials to build them out of. Here were the main contenders:
I’m going to give you a full tutorial for how to make these beds at the bottom of this post, but first, I’ve been getting a lot of questions about these beds, so let me answer those.
Moles. And weeds. Moles and weeds are jerks. And we have a lot of both them. Moles love to burrow through our garden and just destroy our garden beds, so we’re hoping the 30-year landscape fabric we used will keep them out. Same with the weeds, to a lesser extent. Most weeds won’t be able to germinate up through two feet of soil, but honestly, our weeds are so relentless, I wouldn’t put it past them. So we erred on the side of too much weed control as opposed to too little. We will be covering all the landscape fabric with crushed or pea gravel later in the season.
Landscape fabric is a necessary evil for us. I don’t love having a petroleum-based product at the bottom of our beds, but I think if we didn’t put it down, we would have been kicking ourselves for years. We investigated some other weed and mole control methods, but none of them seemed as sure as landscape fabric (by the way, this is the weed fabric we always use—it’s really great quality and, if you have a Prime account, Amazon is the cheapest place we’ve found to buy it and get it shipped). I take some comfort in the fact that the fabric is below two feet of soil—hopefully any chemical leaching the fabric does will leach down and not up.
One thing we did have to adjust because of the fabric—we had to bring in worms! Worms probably would have eventually found their way through the seams of the fabric into our beds, but we sped up the process a bit by inoculating our beds with nightcrawlers from Uncle Jim’s Worm Farm.
The depth of our beds is 26″—the same width as the galvanized steel roofing panels. Could we have cut them down to make shorter beds? Absolutely, but we didn’t want to for a few reasons. The obvious one is that a higher bed makes for less back-breaking work. Our beds are high enough that we can comfortably sit on the sides and weed or bend over to harvest without feeling like our knees and backs are taking a beating. This isn’t a huge deal right now since we are in our mid-thirties, but since we want these to be long-term beds, we were thinking about future Cass and Craig. In 10, 15, 20 years, I think we’ll be thanking our past selves for making higher beds.
The second main reason is that plants want way more soil than you imagine they would. They like lots of space for their roots to spread out—especially plants with long taproots like carrots. Honestly, the more soil space you can give your plants, the happier they’ll be.
The only con to these mega deep beds is the amount of soil you need to fill them. We brought in weed-seed-free soil and compost from a local company, and the volume just makes it a lot more expensive. But thankfully, it’s a one time expense.
The galvanized steel panels, conduit, and corner covers will last 30-60 years. The cedar supports will probably be a bit less—closer to 20 years. If we get 20 years out of these babies, I’ll be thrilled.
Yes, and it’s laughably simple! We didn’t fill our beds 100% to the top with soil—we left about six inches clear—so we can cold frame the beds without much effort at all. Literally, our “cold frame” is just a plastic greenhouse panel laid on top with some bricks to hold it down.
This works so well, it’s amazing! On a 30° and sunny day, it was up to 75° in the bed within about five minutes of putting the panel on. The best part about this? It was totally free. We screw these panels into the side of our chicken coop in the winter to act as a windbreak in their run—so when we took them off for spring, we just moved them onto our garden beds!
We had a big dump truck load of half garden soil and half organic compost delivered to our house. The garden soil is a mixture of screened topsoil and sand (to help with drainage). We then tested the soil and amended it as necessary in each bed. Each year, we’ll top dress the beds with more compost and worm castings.
I wasn’t planning to post a full tutorial for these beds, but since I’ve been talking about them over on Instagram, so many people have been asking about them, so I asked my husband to write up a full tutorial for how to build them. We’ve tried to be as clear as possible (and provide lots of photos), but if you have any questions, just leave a comment or shoot me an email.
(download a printable version here)
Click any item to see an example and/or purchase online.
1. On a flat surface big enough for a 8′ x 4′ raised bed, lay down two 26″ x 4″ x 4″ cedar boards parallel to each other roughly 8′ apart (photo 1A). Take one 8′ corrugated panel, and place the panel so that it rests on top of your 4″ x 4″ pieces at each end, like a bridge—making sure the outside edge of the panels curve upward and the edge of each panel is flush with the edge of the 4″ x 4″ (photo 1B). Using four of the 1″ self-drill screws for each end, screw the panel to the 4″ x 4 ” piece, starting at the top groove of the panel and skipping two grooves for each screw (photo 1C). Repeat this step with your other 8′ corrugated panel and two more of the 26″ x 4″ x 4″ pieces (photo 1D).
2. Have someone assist you by lifting up one of the previously assembled panels and holding it in an upright position (photo 2A). Take one of the half-cut corrugated panel and place it against either end of the assembled 8′ panel, creating a 90-degree corner of your bed (photo 2B). Using four more 1″ self-drill screws, screw it into the 4″ x 4″ through the top ridge of the panel, skipping two ridges for each screw, just as previously done (photo 2C). Repeat this step with your other half panel on the other end, creating another corner of your bed (photo 2D).
3. Have your assistant lift the other 8′ assembled panel and hold it in place between the two half panel ends to create the other side of your bed and the other two corners of it (photo 3A). Screw through the half panels and into the 4″ x 4″ corner supports on the assembled 8′ side your assistant is holding (photo 3B). You should now have a four-sided 4′ x 8′ raised bed. Place your bed as it currently is in the location that you want it to be permanently (photo 3C).
4. Grab the eight 40″ lengths of conduit, tape measure, and sledge, as you will now be anchoring your bed in place. Start by measuring the halfway point on any side (photo 4A). Getting as close to the panel as possible, start hammering in one of the pieces of conduit into the ground at this point to about a 6″ depth (photo 4B). Repeat this step on the other three sides and then make sure your bed is still placed the way you want it, as you may have shifted it slightly when you started hammering in the conduit. Adjust as needed. On one of the 8’ sides, measure the halfway point between the previously hammered conduit and the end of the bed and hammer another length of conduit here (photo 4C). Do this on both sides of the originally hammered conduit. Repeat on the other 8′ side. Hammer all conduit in until the tops are level with the top of your corner 4″ x 4″ posts (photo 4D).
5. Take your two remaining 4″ x 4″ pieces and place these in the middle of each 8′ panel on the inside of the bed, for added support of the top rails (photo 5A). Place the 4″ x 4″ on the inside, just to the left or right of where the conduit is on the outside, and screw in using your 1″ self-drill screws (photo 5B). Repeat on other side (photo 5C).
6. To do the top rails, place one of your 99 3/4″ x 2″ x 6″ rail pieces on top of the 4″ x 4″ supports on the 8′ side (photo 6A). Make sure the inside edge matches up with the inside corner of the 4″ x 4″ corner post (photo 6B). Using one to two 3″ screws per 4″ x 4″, fasten the rail into the 4″ x 4″ (photo 6C). You may run into an issue regarding your conduit sticking up too high. Just lightly hammer the 2″ x 6″ rail until it is able to rest upon the 4″ x 4″ supports.
7. Next, place a 51 ¾″ board on one end so it hugs the 45 degree angle of the top rail that was just fastened (photo 7A). Using 3″ deck screws, fasten this board to the corner and middle 4″ x 4″ supports (photo 7B). Then, place both the remaining 99 3/4″ top rail and the 51 3/4″ top rail at the same time (photo 7C). Wiggle and adjust them so they can fit snuggly into the already fastened rails. Once they are flush, fasten them to each corner support and the two middle supports with 3″ deck screws (photo 7D).
8. Attach the galvanized roof edge to each corner to prevent injury from the edges of the sharp roof panels (photo 8A). Each 26″ corner piece will require four of the self-drill screws to fasten it, two at the top of each side and two at the bottom of each side into the corners of the bed (photo 8B). Repeat with all four corners (photo 8C).
9. The finishing touch is to sand down your cedar top rails to ensure that no splinters are going to happen when sitting on your beautiful new cedar/galvanized raised beds (photo 9A). Then fill up your bed with soil, plant, and enjoy (photo 9B)!
Happy planting, friends!
Subscribers get first access to new content, exclusive recipes, giveaways, tons of freebies, behind-the-scenes updates, and a totally free eBook just for signing up!
Your email address will not be published. Required fields are marked *
These are AWESOME!!!! I’m so excited to see them in all their veggie glory. I can see the vines spilling out now. So excited for you to do this, I’m doing something like this next year and can’t wait for the weed control aspect! Thank you for sharing!
I’ve been waiting for this post since I saw the pics/videos on insta and I am SO impressed and thankful you posted the in depth tutorial! We have a lot of projects going right now but I’m adding this to the list when we get to setting up our veggie garden!
We built an 8×4 a 10×4 and a 12×4 in 8 hours using galvanized metal and redwood that look more professional and aesthetically pleasing. Material cost for all $700. Far sturdier as well with 24 Gage steel side walls. Let me know if you want pics. I appreciate your efforts cause I know what it takes to do this. But, I believe we have a better nicer looking result. Cheers.
And no angles to cut….
Sure, feel free to share your designs. We’re very happy with ours, but I’m always open to hearing improvements!
How can we get your design, instructions, and materials list for the no angles to cut method?
Wow! This looks awesome! You may have already done a post about building a swing set, but just curious if you built it or bought a set? I’ve been looking and that look so much nicer than all the wood ones I see everywhere.
We bought it! We *really* wanted a low-to-no maintenance play set, and we ended up finding this one at Costco (but then eventually bought it from Sam’s Club—it was a few hundred bucks cheaper). It costs a bit more than the wooden ones, but we figure we’ll more than make up for the added price by getting to skip yearly sealing and other maintenance!
It’s listed at $1400 right now, but we got it for $999, so wait until it goes on sale! https://www.samsclub.com/sams/lifetime-adventure-tower-playset/prod13470037.ip?xid=plp1110195-toys:product:1:10
These are soooooo pretty! :)
Thank you for sharing the tutorial, Cassie, as well as some background information on why this is a good idea! (First time gardener here. :))
I think that’s a very rare idea. But cool!
Looks good, I really like the idea of using the corrugated metal on the sides. it makes it look cleaner. I am going to have to do this next year. Thank you for the plans
What ARE the steel corner covers? Where did you get them?
Those are the galvanized roof edges – step 8!
have been looking for this project for a long time. thanks for step by step instructions
Thank you so much for this post! This material combination seems like a perfect way to get the durability/depth out of the garden without the huge price tag of only cedar. After constructing these, do you see any problem with making a bed double in length? I’d overlap the corrugated metal in the middle with similar post/conduit spacing. I just didn’t know if strength/rigidity would be sacrificed. Thanks for your thoughts!
Hmmm, I think if I did that, I would add another cedar support in the middle on each of the long sides. The conduit is strong, but even on our 8 foot beds, the sides bow ever so slightly when filled with soil.
Love your raised beds. I became a fan of galvanized beds while watching the Australian gardeners on youtube. They have access to some fabulous galvanized beds that I wish we could get in the US. I built 6 4’x10′ beds similar to yours but essentially made a frame of 4″ x 4″ walls and then installed the galvanized roofing on the inside (kind of like installing drywall on a stud wall). That way the edges were inside. We put a 2″x6″ cap on top like yours. We kept the full width of the panels so they are also 26+” tall. Some other suggestions for these types of raised beds are putting 1/4″ hardware cloth in the bottom in addition to the landscape fabric – keeps the moles/vole out. We haven’t had one invasion. Also applying Hugelkultur techniques can significantly reduce watering requirements. We filled the bottom 1/3 of the beds with logs (3″ – 10″ in diameter), twigs, leaves, grass clippings, wood chips, etc. The rest of the bed is filled with a combination of compost and container mix. We threw in some extra Nitrogen for the first season as the decomposing wood can draw out some Nitrogen. Finally, soaker hoses on timers sitting on top of the soil completed the project. We mulch when we plant and sometimes use black plastic compost depending on what we’re planting. The combination of mulching and the buried logs really helps reduce the need for water and eventually the wood decomposes into lovely soil. Plus we saved $$ on soil by adding the logs. You do need to make sure the logs are local so you don’t import any nasty insects, etc and haven’t been pulled out of some horrific weed patch. Also some types of wood shouldn’t be used as they are detrimental to growing plants (cedar, black locust, black walnut). How have you been managing crop rotations? We use intensive companion planting and find that sometimes all of our beds have had combinations of all the plant families so in theory we’re not supposed to plant any of the families the following year! Also , how far apart are your beds? We left enough room for a wheel barrow (~ 3+ feet). We’ve had some interesting cross breeding happen between zucchini and spaghetti squash! So I think the beds should be farther apart. Thank you for all the wonderful content you provide!
Love your idea! How do you water them?
How many worms would you recommend?
We did ~100 night crawlers per 4×8 bed.
the link to menards for the corrugated galvanized panel does not work, where do I get the 24ga corrugated panel from? all I can find is 32ga? is this too thin?
also I’m looking to do longer sections than 8ft, how would you recommended but jointing two pieces of corrugated sheeting?
I can’t say on the 32ga panels—I’ve never worked with them. And if you have enough overlap of the panels and enough conduit, I think you’d be okay.
I would frame that entire box, A -bracket the corners and put some cross beams. That wet soil is a lot of weight pushing out of those gavalnized sheets. And those pipes are not enough to hold the weight of the soil.
They’re doing fine for us! But if you want to frame it out, go for it. :)
These are perfect! Been looking for beautiful raised beds using metal. I would love to have 12 beds as well. Planning to put 3′ between beds so I can get a wheelbarrow between. Also, I was thinking of cutting out small portion in center of the landscape fabric so native worms can populate the beds. Can put some 1/4″ hardware cloth over cutout portion to keep out the moles but let the wormies through :) Also thinking of using logs in bottom to take up some of the space. Like Hugelkulture beds. It will help with water retention and Mycorrhizal growth. Thank you so much for great DIY tutorial and video!
Should I use a plastic lining under my raised garden beds to prevent roots from intruding?
You can if you want, although I would recommend a breathable, water-permeable landscape fabric instead of plastic for drainage sake.
I just sent you a message using your “contact” page. I would love your advice for building beds in our community garden! I’m hoping to hear form you soon.
At Wholefully, we believe
vibrant, glowing health
is your birthright.
The free Living Wholefully Starter Guide is packed full of tips, tricks, recipes, and a 14-day meal plan to get you started on the road to vibrant health.
Welcome to Wholefully! Our goal is to empower you to take control of your own health. Let us show you the holistic wellness tools you need to nourish your body and uplift your mind.
In this totally free (yup!) digital book, I share with you everything you need to get started living the Wholefully life—clean eating, green beauty, natural home, self-care, mental health—we cover it all!
Many outgoing links on Wholefully are affiliate links. If you purchase a product after clicking an affiliate link, I receive a small percentage of the sale for referring you, at no extra cost to you. Wholefully/Back to Her Roots, LLC is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.
Any specific health claim or nutritional claims or information provided on the website are for informational purposes only. Nothing on the website is offered is intended to be a substitute for professional medical, health, or nutritional advice, diagnosis, or treatment. See full disclosures »
We are using cookies to give you the best experience on our website.
You can find out more about which cookies we are using or switch them off in settings.
Strictly Necessary Cookie should be enabled at all times so that we can save your preferences for cookie settings.
If you disable this cookie, we will not be able to save your preferences. This means that every time you visit this website you will need to enable or disable cookies again.