Don't let your hilly or sloped backyard stop you from making a vegetable garden. There are ways around the slippery slope so you can be growing all your favourite vegetables -- think terraced rice paddies of Asia and you're on the right track. A gentle slope is easy to terrace yourself; however, if you have a very steep slope that you want to turn into a terraced garden, it may pay to consult a landscape engineer to ensure the best placement of terraces and safe and sturdy construction.
Analyse the slope where you want to grow vegetables. Look for any natural terrace-like forms in the land to minimise the work you have to do. If there is already a stairway up the slope, either side is ideal for your vegetable terraces, otherwise you may have to cut in a step or path to access the garden beds.
Put on your gardening gloves and hold the level out straight from the top of the slope where you want to create the first terrace. Hold the yardstick perpendicular to the level and move it until the yardstick says the level is 12 inches from the slope.
Drive a stake into the ground at this point with the mallet, and use the shovel to mark the starting point of the terrace, where the level starts from. There should be half the stake, around 12 inches, protruding above the ground.
Move down the slope around a foot from the first stake, and repeat the process to give the rough dimensions of the second terrace. Continue in this manner down the slope until you have the desired number of terraces.
Return to the first terrace position. Use the blade of the shovel to cut the outline of the terrace bed into the slope. Cut a length of the 1-by-12 lumber to the length of the terrace and position it against the stake you used to mark the 12-inch mark. The top of this piece of lumber should therefore be on level with the starting point of the terrace.
Drive a stake every 2 feet along the outer side of the 12-inch lumber so that it is resting by itself on the stakes, then drive a stake in between each of the outer stakes on the other side of the lumber so that it is sandwiched in place between the stakes.
Measure the distance between the ends of the lumber retaining wall and the start of the slope and cut two pieces of lumber to this length for the sides of the garden bed terrace. Cut one side of each piece of lumber to the gradient of the slope so that the lumber sits level with the retaining wall. Install these two lumber planks as you did the retaining wall, using stakes.
Fill the garden bed with potting soil up to the top of the retaining wall. Repeat the terrace garden bed construction with all the remaining terraces you marked out earlier.
Plant your vegetable seedlings in the terraced garden beds. Plants that like well-drained soil, such as tomatoes or peppers should be planted in the top terraces, while those plants that can tolerate cooler and wetter soils, like lettuce or peas should be planted in the lower terraces. Water all seedlings well with the watering can or hose.