What I've been using to test my organic soil mixes to ensure that they are ready to be used since both the super soil mix and the organic potting soil mix both need to sti around for a little bit of time so that the microbes can break down all the solid nutrients. This soil testing kit is able to check the Nitrogen, Phosphorus, and Potassium levels that are currently bio-available to the soil as well as being able to check the pH of the soil, all for around $2 per test.
Soil Test Kit: [ Ссылка ]
Previous 4 Part Series on Building a Soil Series:
Part 1: Building an Inert Potting Mix - [ Ссылка ]
Part 2: Building an Organic Seed Starting Mix - [ Ссылка ]
Part 3: Building an Organic Potting Soil - [ Ссылка ]
Part 4: Building an Organic Super Soil - [ Ссылка ]
Bonus: Soil Amendments - [ Ссылка ]
