Module Overview
In this module you will be introduced to the importance of and technique for soil testing and achieving optimum fertility.
Learning Goals
After this module, learners will be able to:
- List at least 6 macro and micro nutrients needed for plant success.
- Describe the soil testing process
- Interpret a soil test result (or identify where you can go for help with interpretation)
- Define soil pH
Roadmap
These items will all appear, in order, in the module.
- READ: Why Test My Soil?
- ADDITIONAL RESOURCE: Order a Soil Test Kit from Franklin County
- ADDITIONAL RESOURCE: Soil Testing for Ohio Lawns, Landscapes, Fruit Crops, and Vegetable Gardens
- ADDITIONAL RESOURCE: Interpreting a Soil Test Report
Please click NEXT at the bottom of this page to advance through the module. To return to the list of modules, PC users click “Modules” in the top left corner, App users click the back arrow in the top left header.
Why Test My Soil?
Nutrients and pH
Plants require 17 nutrients for growth. They get three of these nutrients — carbon, hydrogen, and oxygen — from air and water. The other 14 nutrients need to be provided to plants via organic matter or fertilizer. These nutrients are all rate limiting, which means if you do not have enough of even one of them, the plant will stop growing, and may eventually die.
The nutrients needed by plants are characterized as macro-nutrients — meaning the plants need lots of them — and micro-nutrients — meaning that plants only need a small amount. The major macro-nutrients are nitrogen, phosphorus, and potassium. Other important nutrients include calcium, magnesium, sulfur, manganese, boron, zinc, copper, iron, molybdenum, chlorine, and nickel.
Plants also require a certain pH of soil to uptake nutrients and grow properly. We define pH as how acidic or basic something is. The scale has values ranging from zero (the most acidic) to 14 (the most basic). Each plant has its own favorite pH range, although most vegetables do well when the soil pH is close to 7.0, or true neutral.
Soil Testing
The best way to get knowledge of your soil’s nutrient levels, the soil pH, and what amount of fertilizer is needed to achieve optimal growth is to do a soil test. A soil test involves taking a small amount of soil, about one cup, and submitting it to a testing lab for evaluation. The lab will give a recommendation for adjusting pH and for adding nutrients based on what you tell them you want to grow. We recommend testing your soil about every three years to make sure the pH range and fertility levels are optimal for plant growth. Your Extension office will have information on where you can purchase soil test kits and will help evaluate the results when you get your test results back.
Soil Fertility Tips
- The bagged soil we add to raised beds has only a small amount of fertilizer in it and will not provide a whole year of fertilization for your plants.
Fertilizer can be added as a granular fertilizer to the soil or as a water-soluble fertilizer to a watering can. Granular fertilizer feeds for a longer time but takes more time to be made available to the plants. Water-soluble fertilizer provides nutrition faster but is only present in the soil for a week or two, so it needs to be added periodically during the growing season.
- Heavy rainfall or irrigation can leach the fertilizer out of your soil and may necessitate replacement of fertilizer.
- If you cannot get a soil test done, follow the label instructions on the package of fertilizer each season.
- If you do not fertilize to address the needs of what you want to grow, you will not get the harvest that you want, but you will still likely get a bumper crop of weeds!
Please click NEXT at the bottom of this page to advance through the module. To return to the list of modules, PC users click “Modules” in the top left corner, App users click the back arrow in the top left header.
