by M. Arjoca, vegetalshapes.com
When you choose the space where to make raised beds you have to keep in mind that the plants need a large quantity of light. If the place is semy-shaded you can grow plants which tolerate partial shade.
Once you chose the place mark and measure it. Usually the raised beds have rectangular shape but they can be circular too, depending on the available space and on the personal taste. The height of 25-30 cm (10-12") is ok, but it can be bigger, for example it can be high enough for working just standing near the bed.
You have to think about how deep the roots grow. Some plants have shallow roots but others have deep roots.
Generally the width of the beds must be not bigger than 1,20 m (4 ft). The idea is that you must be able to rich the center of the bed from both sides when you stretch your hand.
You can use different materials for building raised beds: wood boards and beams, plastic or metal boards, stones, bricks, concrete etc. If you choose to make them from wood be careful that it's not treated with dangerous preservatives.
Mark the places where the beds will be and let some space between them for paths. Clean the place from weeds, stones, branches, other materials and dig the surface of the soil. Build from selected materials a frame (without bottom) with the dimensions and form you want. The frame must be solid enough to keep the soil steady and not to break on a simple touch or when you water.
Fill the bed with fertile soil (working with a fork you can make a mixture as you like). Don’t underestimate the quantity of soil you will put in.
When everything is ready you can start sowing and planting. The plants grow closer than in a common bed because you must use the space at maximum and to be efficient you can grow companion plants. The plants can be on closed rows, every row having a different number of plants. For example, if you have 5 pepper plants on a row, on the next row you will have 4 plants, each plant from the last row being placed in the space between another 2 plants from the first row. You can see this in the images below.
You can put shredded wood or stone mulch, paving stones, wood boards etc on paths for having access in garden on any weather. This way working there is very pleasant.