what you need to know about building raised bed vegetable gardens

Considering growing more edibles next year?  I am.  A common and easy way to add a vegetable garden is a raised bed.  Raised beds can be built quickly and on top of any surface (except contaminated soil, for obvious reasons), and will provide a place to add clean, weed-free soil which will make gardening easy.  They also warm up faster in spring, and are easy to add hoops and frost covers to.

Above: some raised beds installed by one of my clients last summer.

Here are a few important considerations I gave her during the design phase:

MATERIALS

• anything works when used properly: wood, brick, stone, plastic, metal.  But wood is easy to work with and fairly cheap.  Cedar is a great choice because it is naturally rot resistant.  DON'T use treated wood!
• if recycling some kind of container, make sure there is good drainage by removing the bottom or adding plenty of holes.

LOCATION, LOCATION, LOCATION

• if at all possible, do not compromise on this point!  A veggie garden requires plenty of sunshine - at least 6 hours in the middle of the day.
• maximize the heat too - the garden shown above will receive plenty of extra warmth and shelter from the south-facing wall of the house, as well as the gravel which will absorb the warmth of the sun and radiate extra heat during the night.  My own veggie area, shown in progress below, is on the south side of a fence and includes recycled concrete stepping stones for absorbing daytime heat. (Don't worry, the garbage in the back corner will be gone!)

ACCESS

• one of the key benefits of raised beds, after the ease of building, is that the soil never gets stepped on, so make sure you build them so that you can reach far enough into them without compressing the soil.  A general rule is to make the bed max 4 ft wide if you can access it from both sides, and 2 ft wide if you can only access it from one side.
• if bending over is an issue for your back, the higher the beds are, the better.  But generally the depth should be at least 6 in (15 cm) deep or at least 1-2 ft (30 - 60 cm) if you are building on an impermeable surface.
• easy access is essential, and raised beds can look so neat and orderly that you don't have to hide them in the back corner of your yard!
• if building more than one bed, make sure you can navigate the pathways with your wheelbarrow.

IRRIGATION

• veggie-growing is not low maintenance; you will need a convenient water source.
• that said, if you are always at home, hand watering from a rain barrel could be all you really need.
• if you've got a large garden planned, consider getting water plumbed to the area (before you build!), and/or use water timers and a sprinkler or irrigation system if you are away a lot.

INSTALLATION

• if the bed will be shallow, remove any weeds before building.
• if it will be 30 cm deep or more, the new soil should smother any weeds below, but it's not a bad idea to put a thick layer of cardboard or newspaper down first just in case.  The paper/cardboard will decompose over time, but may initially interfere with deep-rooted vegetables if the raised bed is not very deep.

DESIGN

• the two examples I've shown above used 4x8 ft rectangular beds, but there's no reason to limit yourself! 
• be creative: if you have the space you can do anything from a series of squares, to spirals, to a radiating, pie-shaped design.
• this website has some great design possibilities to get you started dreaming.  If I had more space, I'd be all over these designs!
• a gallery of raised bed designs from Fine Gardening
• have fun with it - add some pretty pots, funky trellises or garden art on the walls, and an inviting place to sit.

From the archives:

When to plant vegetable seeds in Calgary.

If you would like a help developing a beautiful and successful garden that nourishes your body and soul, view My Services for consultation details.

Comments

[dillards bedding]

I've always dreamed of having my own backyard garden where I could depend for some fresh vegetables for daily consumption. It's really fun to have something like this at home where everyone could bond together while enjoying the nurturing of the garden itself and later on enjoying the bountiful harvest as well.

[Kate C]

hi there,
I am building a couple raised beds for my garden in Calgary and the sale man suggested to stain our untreated spruce wood planks so it will last longer. He suggested to stain the outside of the boxes with wood stain and use cooking oil on the inside that come in contact with the soil. I'm not sure about it. I read a few gardening books and none of them mentioned staining the wood. I'm not sure if it is the cold weather in Calgary that "staining" is needed. Would you say it is necessary? Thank you!

[Calgary Garden Coach]

Hi there,
I prefer cedar which is naturally rot-resistant, and then stain is not as much of an issue. The oil or stain is suggested because it will help preserve the wood, as it will be in contact with wet soil. So yes, some kind of treatment will make your wood last longer. Since spruce isn't as rot resistant, I would definitely use something. But I used tung oil rather than cooking oil, as it is thick and will provide much more protection. Tung oil could be put on the outside as well, and re-done every year. I would prefer that to stain, personally, to be on the safe side.
Janice

[EmmaCay]

Wow, what and amazing garden. I just love your grow boxes. I would love to have my own garden just like this one.

[Lance]

This is perfect for what i want to do Thank you. Im not sure how to do irrigation in calgary i have seen a lot of people use different methods, but you have great ideas thanks again!