Wednesday, April 22, 2009

How to Build a Raised Garden Bed

Building a Raised Garden Bed

Building a raised garden bed is easier than you think. You can build them on top of grass, dirt, rocks, patios, roofs, wood, just about anywhere. But for this post, let's just say you want one in the backyard. You can build it right on the lawn and don't worry about removing the grass or sod it will just compost under the soil you place in the bed and help add to the soil quality. Not to mention worms like it and worms are a gardeners friend because they help aerate the soil.

Now where you place the beds is the first consideration. You want the beds to get at least 6hrs of sunlight or more. I've had the most success with placing them up against a south facing wall or fence. This way you get some reflective sunlight and heat transfer. I live in the panhandle of North Idaho and so being in a northern climate zone, I need to maximize heat and sun to have a successful growing season. Because the beds are usually rectangle in shape, I would orient them so that the ends are facing north and south and the sides are facing east and west. This also helps your plants get maximum sunlight.

Building the raised bed is easy, just about anyone one can build it. For the easiest and most cost effective plan, build a 4x8ft bed using standard lumber. For a basic design, use standard lumber either in 2x8, 2x1o or 2x12 size, in lengths of 8ft. For one bed you'll need just 4 boards, cut 2 boards in half or in 4ft lengths. Now, form a rectangle by placing the 4ft lengths on the ends of the 8ft lengths and you have a rectangle. You can nail them together, but I recommend you screw them together so they don't pull apart so easily.

Also, I would recommend you place the 4ft ends on the outside of the 8ft sides, then screw them together, this will help prevent them from pulling apart because the sides take most of the pressure. You can also screw stakes on the inside of the boards to help them from pulling apart or spreading because of the weight of the dirt.

You should now have a 4x8ft box. This seems to be the ideal size for a raised garden bed. You can make them longer (longer costs more), but I would not make them wider. 4ft seems to be the ideal width, so that from either side of the raised bed you can still reach the center. Any wider and people have a hard time reaching the center and then have to kneel or step in the bed or lean in with one hand down, hence compacting the soil. Besides, 4ft uses standard lumber size, doesn't waste any wood (just cut in half) and is therefore cheaper and more cost effective. Trust me on this one, don't go any wider than 4ft.

Now if you don't want to bend over, you can always add another rectangle on top by building another box and then just screwing strips of wood on the inside to hold each level together. With 2x12 lumber, 2 levels seems to be enough and I definitely wouldn't go higher than 3ft. Remember, you still need to fill the bed with dirt and the higher you go the more dirt you need.

Finally, fill your bed with some good garden soil (this is probably the hardest part of building a raised bed). Look in your local "Thrifty Nickel" or paper and you can usually find someone trying to get rid of manure, just make sure its aged and then just mix in some dirt.

Here's a 2x12x8ft bed.

Here's a side view so you can see spacing, you want about 2ft between each bed so you can maneuver. NOTE: If you have it on grass, I would make sure it's big enough for your lawnmower to fit between.

You can start with one bed, but I think 3 is the ideal for a small family.

If you use treated lumber (like in the photo) or railroad ties, you'll need to line the inside with plastic. This will prevent chemicals from leaching into the soil.

Here's some beds on the side of a house and one has a frame of sticks for the peas to climb on and another has boards nailed on the sides to make a frame for climbing plants.

Building raised beds is easy and if you pay attention to your local classified ads, you can often find most of your material for free. This is just one way to build raised beds, in some later posts, I'll show you a few other ways.

Happy gardening,


1 comment:

Neko said...

great information, thanks!