How raised bed corners are connected together is the trickiest part of building any raised bed vegetable garden. Lumber wants to swell, shrink and twist, especially when it is wet on one side (inside where the soil is) and dry on the other (the outside).
On top of that, screws driven into the end grain of wood don't bite very well, so you can't just screw the side of one board into the end of another without some kind of reinforcement.
So I've searched the web for some good sturdy raised bed corners that solve this problem quickly and easily. You can click on the pictures to see each product page for detailed information and reviews:
Aquacorner Self-Watering Corner System...
Any of these corners are good choices. They save you work, because you really only need a screwdriver (and perhaps a hand saw to cut your boards to length) to put together your own raised bed.
In addition to holding the boards straight, pre-made corners solve another challenge. The weight of all the potting soil, plants and water on the inside of a raised bed garden exerts a lot of outward pressure, and these corners will not "blow out".
If you are only building a small, 6" deep raised bed, there is not that much outward pressure, but the deeper and larger a raised bed that you build, the heavier the lumber and the stronger the corners will need to be.
For example, raised bed gardens intended for wheelchair access need to be a couple of feet high, so they need to be built of strong timbers such as 4x4s or 4x6s. These are too big for any of the pre-made corners shown here. If you want to build one of these large, deep raised beds, see the Raised Bed Construction article.
They come in different heights and designs, and some are stackable so that you can turn a 6” high bed into a 12” high bed using the same style corners.
Some are fixed at 90°, and some are actually hinged so you can make raised bed gardens in polygon shapes or even with curved-edges, rather than just squares or rectangles.
So the things to consider before choosing which style to buy are:
For more details about specific aspects of raised bed vegetable gardening, visit these related articles:
"It is good to be alone in a garden at dawn or
dark so that all its shy presences may haunt you and possess you in a reverie
of suspended thought."
--- James Douglas
"True gardeners cannot bear a glove between the sure touch and the tender