1. Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
Curriculum for Agricultural Science Education Copyright 2015

2. Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
Principles of Agricultural Science – Plant
Potting Media Components Unit 3 – Soilless Systems Lesson 3.1 Mixing Media
This presentation will examine the components added to potting media.
Curriculum for Agricultural Science Education Copyright 2015

3. Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
Potting Media Goals
Growing crops in containers require:
Light weight potting media for shipping and handling
Good porosity for drainage and aeration
Good water retention to prevent containers from drying out too quickly
Inexpensive
Cost effectiveness is key for whatever ingredients are used in media.
Curriculum for Agricultural Science Education Copyright 2015

4. Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
Media Ingredients
Three types of ingredients are used in potting media
Inorganic materials – minerals and substances derived from non-living matter
Organic materials – substances derived from plant or animal tissues
Soil enhancers – includes fertilizers, wetting agents, and soil chemistry buffers
These materials will be discussed further in the next slides.
Curriculum for Agricultural Science Education Copyright 2015

5. Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
Inorganic Materials
For potting media, inorganic materials are typically light weight and very porous volcanic materials such as:
Perlite
Pumice
Vermiculite
The quantity of these materials will depend upon the type of plants being grown in the media mix.
Curriculum for Agricultural Science Education Copyright 2015

6. Other Inorganic Materials
Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
Other Inorganic Materials
Besides volcanic materials, man-made materials are used, such as:
Plastic polymer beads
Clay beads
Rockwool
Anything inexpensive, light, and that will not disintegrate in wet conditions.
These are considered filler materials.
Curriculum for Agricultural Science Education Copyright 2015

7. Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
Organics
Organic materials absorb water and break down to provide improved porosity
Common materials used in potting media:
Peat moss (sphagnum peat)
Bark chips
Sawdust
Coconut fibers
Seed hulls and husks
These materials degrade over time but very slowly. They are light weight and porous. These materials are equivalent to organic matter you learned about in Lesson 2.2 Understanding Soil Properties.
Curriculum for Agricultural Science Education Copyright 2015

8. Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
Soil Enhancers
Because potting media provides plant roots access to everything they require, media can have enhancers mixed in for efficient plant growth.
Some enhancement amendments:
Fertilizers
Wetting agents
Lime or gypsum
Soil pH and plant nutrient levels are important to provide prior to planting.
Curriculum for Agricultural Science Education Copyright 2015

9. Slow Release Fertilizers
Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
Slow Release Fertilizers
Potting media can be mixed with time release fertilizer pellets to provide steady plant nutrients over the length of the growing season.
Common product name is Osmocote®. These look like little round clay pellets.
There are many different types of slow release fertilizers on the market. It is good to mix these in at the time of planting according to the directions printed on the bag.
Curriculum for Agricultural Science Education Copyright 2015

10. Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
Purchasing Media
Potting media is typically sold two ways
Bulk – loose, sold by the cubic yard
Packaged – compressed in plastic wrapped bales, sold by the cubic feet
Note the difference in units of measurement between cubic yards and cubic feet.
Curriculum for Agricultural Science Education Copyright 2015

11. Potting Media Components
Principles of Agricultural Science – Plant
Unit 3 – Lesson 3.1 Mixing Media
References
Boodley, J. W. (1998). The commercial greenhouse (2nd ed.). Albany, NY: Delmar.
Parker, R. (2010). Plant and soil science: Fundamentals and applications. Clifton Park, NY: Delmar.
Curriculum for Agricultural Science Education Copyright 2015