Most organic fertilizers contain relatively low concentrations of actual nutrients.
In fact unlike traditional fertilizers, organic materials are often sold as soil conditioners or soil amendments and don't even have a nutrient guarantee on the package. Organic fertilizers use nature's own slow release process to make nutrients available. They are less likely to burn plants because it usually takes a longer time to release the nutrients they contain. Unfortunately, these same slow release properties can be a drawback because organic fertilizers may not release enough nutrients when your plant needs them for best growth. Before you apply any fertilizer, run a soil test and use these test results to calculate your crop's fertilizer needs.