How to Build a Raised Bed Step-by-Step

, written by Benedict Vanheems gb flag

Raised bed vegetable garden

Spring has sprung - but there's still time to start a raised bed! In this short video and article, we'll demonstrate how easy it is to build a small 4ft x 4ft (1.2m x 1.2m) raised bed from scratch.

For this project we've used two planks of wood that are 8 feet (2.4m) long. By cutting these in half this makes a square bed that is 4 feet (1.2m) long on each side. The advantage of a bed that size is that you can reach the center from all sides of the bed, so that you never have to step on the soil inside the bed. That means the soil never gets compacted, which helps plants to thrive.

Preparing the Ground

Choose an area of your garden that receives plenty of sun. Start by laying cardboard over the area the new bed will occupy. This will help to clear all the grass and weeds beneath.

The first thing you need to do with any cardboard is to remove any tape and staples. That way you'll be starting with nice clean cardboard that will rot down into the soil over time. This step may seem a little tedious, but it really shouldn't take you too long.

Spread your cardboard all over the growing area, including the paths. This will help to suppress weeds, stop grass growing up through, and keep it nice and clean, ready for the compost to go on top. Overlap the cardboard generously to prevent weeds from creeping up through any gaps. Aim for an overlap of about 6 inches (15cm).

“Pulling
Remove any non-biodegradable tape and staples from cardboard before using it as a base for your raised bed

Building a Raised Bed

With the ground covered, it's time to make your raised bed. Lay out a measuring tape along each plank and clearly mark the halfway point with a pencil. Saw both planks in half to create four the four walls to your raised bed, all of equal length.

Next, drill some pilot holes. These will make it easier to screw the walls together. Use a drill bit that's slightly thinner than the screws themselves. One end of each plank will overlap the end of the next and screw directly into it, so position your pilot holes correspondingly. Two holes in each plank is sufficient.

The walls of the bed need to be laid out so that each plank overlaps the next, with the pilot holes located at the overlapping end.

Screw the walls together using long screws so that each wall is properly secured to the next with a snug, close fit.

“Building
Overlap the ends of the raised bed walls and screw them together

Raised Bed Finishing Touches

With the walls of the raised bed fixed together, it's time to fill it. Add garden compost to the bed. This will give a nutrient-rich, moisture-retentive layer for roots to grow down into - a sensible move with summer approaching. It also introduces lots of beneficial microorganisms to the soil, which will further enhance plant growth.

The compost may be quite lumpy, so you can mix the compost with enriched topsoil specially formulated for vegetable gardening if you wish. Its fine texture means you can get on with sowing and planting immediately. You could use more of your own garden compost if you prefer, but make sure it's completely decomposed and of fine enough consistency to begin planting.

“Filling
Finally, fill your raised bed with a mixture of compost and enriched topsoil

You can lay bark chippings directly onto the cardboard between beds to give a neat-and-tidy finish to pathways. Alternatively, cut away excess cardboard from around the raised bed to leave a simple grass path.

Next comes the fun part - sowing and planting! If you're going to create a raised bed this spring, please let us know what you plan to grow in it in the comments sections below.

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Comments

 
"Does the cardboard need to be without any writing? Or for instance, laundry detergent might have a photo of the product super-imposed on the cardboard...not a photo that can be scraped off..."
Harry on Tuesday 17 April 2018
"Hi Harry. Ideally the cardboard needs to be plain - with just writing printed directly onto the cardboard. Avoid cardboard with shiny surfaces or coloured pictures on it - this will consist of the cardboard and then another glossy layer which won't easily decompose. Packing boxes are best, as is cardboard that internet deliveries often arrive in."
Ben Vanheems on Tuesday 17 April 2018
"my raised bed isnt from this year but from lasts year. it is around 15ftx30ft. bad thing is that is on a slope. a bit rough for me since my entire yard is on a slope haha. i just did an experiment with planting at that time. i just literally took about 50 packets of different veggie seeds and just threw them everywhere in the garden . well it actually paid off pretty well! it grew like a dang jungle! i have so many diff. veggies out there right now. just tried a turnip with its greens for the first time yesterday and it just might be my new favorite! i found out that guy i heard about just throwing the seeds everywhere and forget about plant spacing was right. there are NO weeds in the garden because all the veggies are overpowering and are growing stronger than when i spaced them like suggested. i found out to sometimes throw that out the window for some plants. my next experiment will be with tomato plants. i will try to remember to give updates on the progress. i have some good ideas that i think might work very well."
kevin on Saturday 16 March 2019
"Wow Kevin. Throwing your seeds about has clearly paid off for you! Glad you're having so much success. Please do keep us updated."
Ben Vanheems on Monday 18 March 2019
"what about plants with deep tap roots or carrots? Is this bed deep enough?"
Linda on Sunday 19 April 2020
"Hi Linda. Yes, if the bed is set on top of soil or lawn like the one in the video, then it would be fine for vegetables with long taproots because very long roots would be able to grow down into the original soil beneath the bed."
Ben Vanheems on Monday 20 April 2020
"Unfortunately, I realized that tree roots were the cause of many of my vegetable gardening problems. I understand that there are certain barriers that one can lay down, as opposed to the cardboard shown in the video, that would prevent tree roots from sucking all the moisture away from the vegetables...any suggestions would be appreciated. "
Harry on Monday 20 April 2020
"I can't recommend a particular product, but if you look for a thick, weed-suppressing membrane of some sort, that should do the trick. You want a barrier that keeps the roots separate from the soil in the raised bed, but that still allows moisture to drain through."
Ben Vanheems on Monday 20 April 2020
"Our ground is primarily clay, and we were originally going to get it tilled up, add good dirt, and just plant a traditional garden. However, I'm heavily leaning toward raised beds instead. Would you recommend us still taking this step if we did? I'd hate for my plants' roots to get through the cardboard to the clay and not do well because they found it a dead end. "
Karen on Tuesday 21 April 2020
"I don't think there's any need to do that Karen. If you are putting good stuff into the raised beds and then continuing to add organic matter periodically over the following years, the soil immediately beneath the raised bed will soften and improve in time. This is because the soil live within it - and particularly worms - will move up and back into the raised bed, essentially mixing up the two layers. This will in time soften and break up the clay beneath the raised bed, enabling plant roots to reach deeper down. "
Ben Vanheems on Tuesday 21 April 2020
"Our land is completely block paved. We have tried removing some setts to make a bed but the hard core is too deep. Can you put a raised bed on to the paving with a membrane of some sort underneath? It would only be for flowers."
Dawn on Friday 24 April 2020
"Hi Dawn. Yes indeed you can. The bed would need lining - some permeable landscape fabric would be fine - and then filled and planted as normal. One caveat is that the water draining out from the bottom may pour out from the sides and potentially stain your paving. The only way around that would be to smash down through the paving and hardcore to allow the water to drain vertically, but that doesn't sound like an option for you. But yes, you can certainly pop the raised bed onto a hard surface."
Ben Vanheems on Monday 27 April 2020
"Having mentioned earlier that tree roots were the "root" of my problems, I laid down some landscape and weed block fabric, then refilled the bed with soil (that's the short version of the story). This got me to thinking. Will earth worms still be able to get into the bed if they can't access it from underneath because of the fabric??"
Harry on Sunday 3 May 2020
"Worms have an uncanny ability of finding their way into garden beds and compost bins, no matter what. However, you could make absolutely sure by digging up an area of soil for worms and adding them in manually. But they'll find their way in there eventually."
Ben Vanheems on Monday 4 May 2020
"I have got a wooden bed and it is lined with heavy duty plastic,I intend growing roses in it .Do I need to pierce the plastic for drainage"
yvonne on Saturday 12 September 2020
"Hi Yvonne. Yes, pierce the bottom of the plastic to allow excess moisture to drain through, or else the soil could become saturated."
Ben Vanheems on Monday 14 September 2020
"Thanks for this idea!! I have a terrible time with grubs and they destroy My garden. I’m going to use recycled dresser drawers and remove the bottom to make smaller beds with different varieties of veggies and herbs, tubers, and potatoes for my fall garden. "
Mommy Harris USA on Wednesday 28 October 2020
"Love that idea - please let us know how it goes."
Ben Vanheems on Thursday 29 October 2020
"A neighbour has offered me some ground which in the past was a very good vegetable garden but is now lawn. I have access to seaweed (though getting it to the veg garden will be tricky) but little else and I need to keep the budget down. Can I 1) just put cardboard down to kill off the grass and then plant through the cardboard or 2) cover cardboard in layer of thick seaweed and plant through it in a couple of months time or would I really need to cover the cardboard/seaweed with a layer of soil? Look forward to any thoughts."
Biddy Simpson on Monday 25 January 2021
"Hi Biddy. If the ground is already in good shape then you have a head start. You can start raised beds using no imported soil or compost, either by digging out the paths and then heaping the spoil into the raised beds, thereby sinking the whole garden a little (but keeping the raised beds raised). Or you can simply position your raised beds, securing them into the ground, safe in the knowledge that over time gradual additions of organic matter will, eventually help to fill the raised beds and bring their level raised about the surrounding ground. As far as your situation goes, I would be inclined to put down the cardboard as soon as possible (having mown the lawn right down) in order to kill off the grass. This may take a few months, particularly at this slower time of year. You can pop a thick layer of seaweed on top of the cardboard, which will help to weight it down. If possible, hose down the seaweed before laying it, just to be sure not to much salt gets washed into the soil. In a few months time, with the grass dead and rotting down and the seaweed beginning to break down, planting through into the ground below shouldn't be a problem - just push the seaweed aside at each planting point so the young plants aren't swamped. In this first year I would aim for larger, more robust or sprawling plants, which will be less hit-and-miss and help with clearing the ground for later, smaller crops that need direct sowing. Squashes, sweet corn, potatoes, tomatoes, courgettes/zucchini, chard, brassicas - that sort of thing."
Ben Vanheems on Tuesday 26 January 2021
"I need a deeper bed to cover a old tree stump. Do you have a easy fix at a reasonable cost. I'm 77 yrs old and will do it myself hopefully. please hurry as I want to plant early."
Sandra Borden on Monday 8 February 2021
"Hi Sandra. You could either make a taller raised bed using wooden planks/lumber, securing the planks on top of each other to corner posts fixed on the inside corners. I would also add further rigidity by screwing on corner brackets, as the weight of compost might be a strain on the wood. You might also consider lining the inside walls of the bed with plastic sheeting, to slow rotting and increase the wood's life. Alternatively there may be off-the-shelf solutions with extra depth. When filling, you could fill the bottom half of the bed with pretty much anything, to save on filling it with more expensive potting mix or whatever growing medium you are using. Old bits of wood, prunings, straw - anything organic that can be popped into the bottom to help with the initial fill will suffice. Your tree stump will be great, as it will break down very slowly over many years, slowly releasing it's nutrients to become available for the plants you grow in the raised bed."
Ben Vanheems on Monday 8 February 2021
"I can't plant a garden in the soil in by yard because of lead levels. If I want to plant root vegetables how deep does my raise bed need to be so that the roots don't grow into the soil below"
APRIL D EASTEP on Tuesday 30 March 2021
"If the soil beneath the bed is contaminated, I would strongly advise that the bed is lined, so that there's no chance of any roots reaching down into it. Use a strong permeable liner, or a plastic sheet liner with drainage slits cut into it. For depth, I would look to go to at least 8in/20cm for root crops."
Ben Vanheems on Wednesday 31 March 2021
"Hello, I'm just starting a garden for the very first time. I'm considering a raised bed, 3ft x 8ft x 10in. Is this a good starter size for an ABSOLUTE beginner? Thanks"
Lee Holston on Thursday 1 April 2021
"That sounds perfect Lee - not too big and not too small - enough space to keep you busy but thoroughly enjoying the experience!"
Ben Vanheems on Tuesday 6 April 2021
"I have built three raised beds and planted different vegetables. My concern is the soil. Should I empty them and start from the beginning or apply different technique to make the soil better. "
Bardha Qirezi on Monday 26 April 2021
"If your beds aren't completely full to the rim, then I would just concentrate on adding more organic matter to the surface to improve soil structure and nutrient content."
Ben Vanheems on Monday 26 April 2021
"I am planning to build a new raised bed garden in my front yard because it has full sun. I had very limited success the last 2 years due to lack of sun in the backyard. I will have the thick zoysiagrass cut out in the front yard and moved to the backyard. We have clay soil. Do you recommend having the soil tilled up before I begin building the raised beds as described in your article?"
Carole Prevost on Sunday 6 February 2022
"Would you mind recommending what type of compost and top soil. I am a total beginner and want to make sure if I am spending out that I am putting good stuff in it from the start. Kind regards. "
Jill Wilkinson on Monday 25 April 2022
"Hi Carole. Apologies for the very late reply to your question, which I hadn't noticed till now. I hope it's not too late. But just to say you can simply cover the soil with cardboard or similar and then put your raised bed and fresh growing medium on top of the cardboard. There's no need to dig the over the soil beneath. In time the soil will naturally improve as the growing medium you put on top gets mixed in with the soil by the action of worms etc."
Ben Vanheems on Thursday 28 April 2022
"Hi Jill. You have a few options for filling your bed. You can often find 'vegetable garden topsoil/soil' sold in bulk bags, which will have organic matter added to it to enrich it. I find that compost made from collected garden waste works really well too, but in my experience it can have the odd bit of plastic/glass/other debris in it that slips through. Another option is mushroom compost. All of these can be used on their own or in combination with each other. I'd suggest getting hold of whatever's most affordable and readily available."
Ben Vanheems on Thursday 28 April 2022
"I'm a beginner and I've just taken on my first allotment, the ground is covered with grass (normal grass, not couch or anything like that). Would I need to dig the grass up in the areas I'm planning to put raised beds or just go ahead and lay the cardboard down?"
Lisa Arbon on Monday 3 October 2022
"I'm glad to report that my new raised bed was a success this year, but with a couple of failures. Tomatoes, and peppers did very well (and are still producing). I even got some hot peppers by accident, the seed must have gotten mixed up in the bell pepper seed packet, but they were delicious. All of my zucchini plants were killed by squash vine borer, but I've learned to follow your advice and hope to do better next year. Several of the beets were dug up by some critter. But most of the other plants did fairly well, too. Each of the last 3 years of vegetable gardening has been a fun and learning experience. Keep the tips coming, Ben!"
Carole Prevost on Monday 3 October 2022
"Hi Lisa. Yes indeed, you can just put cardboard down on top of the grass and then shovel on compost/growing medium to plant into. The grass should die off before the cardboard has fully rotten down."
Ben Vanheems on Monday 17 October 2022
"Hi Carole. Brilliant work on your new raised bed. Pleased to read is twas mostly successful. Keep on gardening! :-)"
Ben Vanheems on Monday 17 October 2022

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