1choose the right location
before you decide where to build your raised garden bed, consider how much sun, shade and wind it will get. the choice of location will also depend on the types of plants you want to grow as well.
2measure for the first support post
when you’re building your raised garden bed up against a wall, take into account the thickness of the sleeper that will be attached to your support posts. hold the sleeper up against the wall and mark it off. from that line, mark the width of the sleeper on the wall. repeat this process for the other end of the raised garden bed.
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3measure for the middle post
once you’ve marked out where your end support posts will be, use the tape measure to work out the halfway point between them. mark that spot on the wall with the pencil.
4mark the lines for the support posts
at both ends of the garden bed, use the spirit level to mark straight lines on the wall, where the edge of the support posts will be. measure and mark, half the distance of the width of the sleeper either side of the centre line. use the spirit level to draw the two straight lines.
5mark the height of your garden bed
use the spirit level to mark a straight line across the wall for the height of your garden bed.
6measure and cut the support posts
measure the distance between the ground and the where the top of your garden bed will be. transfer this distance onto the sleeper. put on your safety equipment and use the circular saw to cut the
wooden. cut two other posts so they’re the same length.
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7mark for the holes in the support posts
depending on the length of your support posts, you may need to drill two or three holes in them. mark out where you would like to drill these holes, making sure they’re in the middle of the post.
8drill the holes in the support posts
use the spade drill bit to partially drill the holes in all the support posts. this will allow you to countersink the dynabolt. change drill bits and drill all the way through the support posts
9secure the posts to the wall
hold the post up against the wall, flush with the lines you’ve marked for them. use the hammer drill to drill a pilot hole into the wall. remove the post and finish drilling the holes in the wall. repeat this step for the other posts.
10attach the supports to the wall
place the support posts against the wall. pull the sleeve on the dynabolt back and insert it through the posts. use the ratchet to secure the post to the wall. repeat this to secure all of the support posts.
11measure for the length of the sleepers
measure the distance between the ends of the support posts. mark this distance out on your sleepers. put on your safety equipment and use the circular saw to cut the sleepers to size.
12attach the sleepers to the support posts
you will need someone to help you attach the sleepers to the supports posts. line-up the sleeper so that it’s flush with the ends of the support posts and level with the top of them. pre-drill a hole through the sleeper. secure the sleeper with a batten screw. repeat this process for the other end of the sleeper. then secure the sleepers to the support post with batten screws into each post. repeat process this to attach the second sleeper.
13dig the soil out for the bottom sleeper
using an off-cut from the sleeper, measure how deep a trench you need to dig to be able attach the bottom sleeper. use the shovel to dig the trench. attach the sleeper following the process in step 12.
14dig the trenches for the side and front sleepers
use the shovel to dig the trenches so that they’re deep enough for the side and front sleepers.
15cut and attach the end pieces of the garden bed
once you’ve cut your end pieces to size, pre-drill a hole in the top of one of them and secure it to the bottom sleeper. use the spirit level to check that its level. if necessary push or remove sand from under it. secure the two other end pieces in the same way. repeat this process to attach the end pieces at the other end of your garden bed.
16dig the holes for the front support posts
before you start digging, check that there are no water, gas or electricity pipes below. dig the hole for the support posts at either side of your raised garden bed. make sure the hole is half the depth of the posts you’re sinking and that the front supports are in-line with the back supports. leave a gap of between 50 to 100mm between the top of the support posts and the top of the garden bed.
17attach the front supports to the side sleepers
line up the front support with the edge of the side sleepers. pre-drill two holes into each sleeper. use batten screws to secure the front support to the side sleepers. repeat this process to attach the other front support to the side sleepers.
18measure and cut the front sleepers
measure the distance between the ends of the front support posts. mark this distance onto your sleepers. put on your safety equipment and use the circular saw to cut the front three sleepers.
19secure the front sleepers
have someone help you hold the sleeper so that it’s flush with the ends of the support posts and level with the top of the raised garden bed. pre-drill a hole in one end of the sleeper and secure it with a batten screw. repeat this process at the other end of the sleeper. use two batten screws to secure each sleeper at each end. attach the two other sleepers in the same way.
20check the garden bed is square and level
use the set square to make sure the corners of the garden bed are square. use the spirit level to make sure it’s level. make any necessary adjustments to make sure they are.
21concrete in the front supports
follow the instructions to mix the concrete in a wheelbarrow. shovel the concrete mix into the hole around the front support posts. add enough so that it’s around 100m below the soil level. let the concrete set and backfill the hole with soil.
22waterproof your garden bed
to prevent the soil and water from leeching out of your garden bed, use corflute or black plastic to line your bed. cut the corflute or black plastic to size and use galvanised clout nails to keep them in place.