1. Understanding Growing Media Components
Lesson 4 - 2

2. Next Generation Science/Common Core Standards Addressed!
WHST.9‐12.7 Conduct short as well as more sustained research projects to answer a question (including a self generated question) or solve a problem; narrow or broaden the inquiry when appropriate; synthesize multiple sources on the subject, demonstrating understanding of the subject under investigation. (HS‐LS1‐3)
HSSIC. B.6 Evaluate reports based on data. (HS‐LS2‐6)

3. Bell Work! Describe the components of soil.
2. List the components of a soilless mix.
3. Compare and contrast the use of soil versus a soilless mix.

4. Terms Clay Inorganic Loam Mineral matter Organic matter Pasteurization
Peat Moss
Perlite
Sand
Silt
Soil
Soil Amendment
Soilless Mix
Sterilization
Vermiculite

5. Don’t Judge a Soil by It’s Label!
Never look gift soil in the label!
What is in a soil?
Don’t count your plants before they germinate!
Use this slide to start discussion on what soil has in it and how that affects production.

6. What is Soil? Soil – outer layer of the earth that supports life.
Recipe for Soil
1cu. Air
1cu. Water
1 4/5 cu. Mineral matter
1 tbl. organic matter
Mix thoroughly and let stand.

7. Soil is: 25% air 25% water 45% mineral matter 5% organic matter
Air and water will jockey back and forth, but only account for half the volume.
Most soils in Illinois are around 5% o.m.
The balance is minerals.

8. Soil Composition

9. Mineral Matter
Non-living substances generally thought of as weathered rock.
Soil particles have 3 general sizes
Sand – largest and increases drainage (feels gritty)
Silt – medium size and gives a talc feel
Clay – smallest and higher water holding capacity, feels slick.

10. Soil Particle Comparison

11. Organic Matter Organic matter is living or dead plants and animals.
Organic matter is necessary for plant growth because of its high nutrient content.
Higher O.M. generally increases productivity.
Soil is not used very often in the production of floriculture crops. Soil is very heavy, not always readily available, and can be full of undesirable weed seeds and insects. As a replacement to soil, greenhouse growers are turning to soilless mixes.

12. What’s in a soilless mix?
A soilless mix is a combination of organic and inorganic substances that provide sufficient support for plant growth.
A soilless mix does not contain topsoil.

13. Common components in a soilless mix are:
Peat moss is plant material that originates in bogs. Peat moss has great moisture and nutrient holding capacity.
Perlite is white in color and comes from heat-treated lava rock. Perlite is used in the soil mix to aerate the soil.

14. Components Continued:
Vermiculite comes from the mineral mica and is shiny brown in color. It has high moisture holding capacity and is very lightweight.
Choir is fibers from coconut hulls which is hollow and aids in water and air holding while remaining lightweight.

15. Components Continued:
Sand large soil particles used to reduce overall water holding capacity
Amendments are added to change the air / water relationship of a mix while reducing the cost
Wetting Agents are soaps used to aid water uptake of the dry mix. Also aids in rewetting.

16. The advantages of a soilless mix are:
1. The mix is uniform. It does not vary in components, texture, or nutrients.
2. The mix is sterile. Sterilization is a process that eliminates all disease organisms, in-sects, or weed seeds. Soil mixes often contain these items and a grower who chooses to use a soil mix must pasteurize his or her soil before using it. Pasteurization is the process of heating soil to kill harmful diseases, weed seeds, and insects.
Pasteurization can occur through several methods but is a combination of heat and time.

17. The advantages of a soilless mix are:
3. Soilless mixes can be manipulated to improve the drainage and moisture holding capacity of the mix.
4. A grower can personally mix the combination of components exactly to what he or she needs for their particular crop.
5. Soilless mixes are easier to ship and move because they are lightweight.
Shipping weight of finished product is greatly reduced = saves money = makes money.

18. The disadvantages of a soilless mix are:
1. Fertilizers often need to be added more frequently to the mix because the mixes are lacking in minor plant food elements. Soil contains and holds many of these minor nutrients.
2. When plants are grown outdoors, the wind can blow dry pots over because the mix is very light.

19. The disadvantages of a soilless mix are:
3. It is sometimes difficult to transplant a plant from a soil mix to a soilless one. The roots often will not grow into the new media and the plant will die because it can not absorb any moisture.
4. There is a cost to the media

20. REVIEW

21. What are the ingredients of soil?
Air
Water
O.M.
Mineral Matter

22. What are the sizes of soil particles?
Sand
Silt
Clay

23. What are the materials used for soilless mixes?
Peat
Perlite
Vermiculite
Choir
Amendments – bark, rice hulls, …
Sand
Wetting Agents

24. What are the advantages of mixes?
Uniform
Sterile
Light
Amendable

25. What are the disadvantages of mixes?
Light
Need nutrients
Cost
Transplant issues

26. The End