Folks are always asking how ‘available’ organic nutrients are and how quickly the nutrients become available to plants so we thought we would provide a little input on the subject. So, the answer is ‘that depends’ of course – we can provide you some information here on different components and what factors impact the release cycle but there is no lab analysis available that can provide the precise answers we are always looking for.
On our product pages we indicate a nutrient release range for each product. The range indicates how quickly (rule of thumb) each product may breakdown and require additional applications.
Almost every organic fertilizer component has a percentage of its nutrients immediately available for plant absorption, typically in the range of 1-2%. The majority of the nutrients are in organic compound form which must be mineralized by your soil’s biological population in order to be absorbed by your plants.
Each organic component will release its nutrients over time through these biological processes but the rates will vary depending on the structure of the organic compound. In general, these rates will stack up pretty much how you would expect.
- Plant matter will break down the fastest with the less fibrous material on the faster side.
- Animal based material can be fast (non-bone component) or medium for fibrous and bone-based products.
- Minerals (mined rock) will take the longest with the more sedimentary material being on the faster side.
Product Form – since biological activity is required for most mineralization, the more access the microbial population has to a food source, the faster it will break down. So, finer fertilizer particles (more powdery) have significantly more surface area and therefore greatly improves access for the biological population and therefore speeds up mineralization.
Microbial activity – the bigger and more active the crowd, the more food that will get consumed (mineralized).
Soil pH – soil pH impacts both biological activity as well as a a nutrient’s availability to a plant. So, even if a nutrient has been mineralized, at a certain pH range it is more likely to bind with other molecules and become less soluble for plant absorption.
Soil Moisture – effects microbial activity and nutrient immobilization (movement of nutrients through the soil and therefore to root structure).
Organic Matter – helps store and hold nutrients for plant absorption.
Competition – plants compete with soil biology for some nutrients. If there are not enough nutrients available, a plant will not generally win the competition.