Controlled-release fertilizers (CRFs) have a great potential to increase forest seedling growth and competitiveness at a variety of outplanting sites. However, CRFs are often poorly understood. In order to use them successfully, their formulation, release behavior, and environmental interactions must be considered. This synthesis paper describes types of CRF (organic, nitrogen-reaction products, and coated products) and their associated research findings. The advantages and disadvantages associated with each CRF are also reviewed, and some tips for their usage are offered. Some current research challenges in further understanding the best ways to use CRF in forestry applications are listed.