Particleboards are an important base for furniture production and interior use, and the production process is in general optimized for wood as the main raw material. Monocotyledons such as reed canary grass (Phalaris arundinacea L.) are an interesting raw-material resource for particleboards, especially since monocotyledons are less suitable than most wood species for thermal energy recovery and pulp and papermaking. In this work, the use of reed canary grass for single-layer particleboards was studied. A surface treatment with paper during pressing or a paper coating after pressing were also tested as a way to increase their mechanical properties. A waterborne acryl-based adhesive was used, and this allowed the reed canary grass to be used without any additional pre-treatment. The boards were tested according to the EN 312 standard. The results showed that the boards did not fulfil the requirements of the standard regarding mechanical properties and thickness swelling but that a surface treatment gave a considerable improvement in the mechanical properties. The low mechanical performance of the boards is due to problems related to the production process, where it appears that acrylic adhesive is not favourable for grass-based panel production.