Choose a site for your raised bed that is fairly level, where gardening will be convenient and plants will receive the correct amount of sunlight to accommodate the plants to be planted there. Plants that require full sun need eight to 12 hours of direct sunlight per day. Partial sun requirements indicate five to six hours of unfiltered sun, while partial shade indicates that plants should receive only indirect, filtered sunlight for short periods of time.
Determine the size that your bed will be according to the length of your logs. Make a bed of a size that will allow you to lay logs in even lengths with no cutting. Beds can be lengthened by placing log ends together to create a longer garden. Beds should be narrow enough to allow you to reach the middle from either side. Cut a log in half to make two end pieces of a more accommodating length.
Clear the site of top growth with a hoe and dig out the top 6 inches of soil into a pile to the side, where it won't be in the way. Smooth and level the bed area with a rake, breaking up any large clumps of soil and tossing out rocks.
Mix a growing medium of equal amounts of compost and peat moss and turn it into the soil pile that you set to the side.
Lay out your logs around the outer edges of your site so that the ends of the side logs butt up against the sides of the end logs tightly, to form corners.
Spread chicken wire or hardware cloth across the bottom of your bed and nail it to the insides of the logs to prevent burrowing garden pests.
Fill your newly formed garden bed to the top edge of the logs with the pile of soil mixture, packing dirt into corners and along edges. Level out with a rake, and you are ready to plant.