Controlled release fertilisers are complete fertilisers that contribute to cost-effective maintenance. You only need to fertilise once per year because the nutrients are released in a controlled way. This is due to the organic polymer coating. This coating only releases fertilisers during periods when the temperature is high enough for the plant to actually absorb the nutrients. This prevents leaching of nutrients and the fertiliser can even provide nutrition at the beginning of the next season.
The coating of the controlled release fertiliser is an organic polymer coating. The coating is made of biodegradable materials such as vegetable oils that stimulate and nourish soil life. The coating actually works symbiotically with the soil life.