Sugar beet residues and various additives were used to prepare panels by forming the semi-dry or wet mixtures and pressing the composites at a temperature of 150 °C and pressures of 100–5410 kPa for up to 105 min. The highest panel density and second highest thickness were observed when a combination of calcium hydroxide and boric acid were used as additives using the semi-dry procedure. SEM images revealed that at pressures over 1000 kPa the cell wall structure of sugar beet was completely unrecognizable. The FTIR results indicated that the non-cellulosic polysaccharides contributed significantly to the properties of the panels by acting as adhesives. The best flame retardant parameters were also obtained with the calcium hydroxide/boric acid formulation. In comparison to composites prepared from recycled paper and mixtures of sugar beet shreds with recycled paper, higher density panels were prepared at lower pressure from sugar beet sources.