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Properties of Soils
Unit 5.01
Inorganic vs Organic
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What is the difference?
Organic contains carbon
 Inorganic does not
 Organic is dead plant or animal tissue
 Inorganic is living tissue or minerals
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Organic Media
Peat Moss
 Compost
 Bark
 Sphagnum
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Organic Media
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Peat Moss
Partially decomposed material mined from the
swamps
 Good moisture holding properties
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Organic Media
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Compost
Decayed organic matter
 Used for soil conditioning and fertilization
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Organic Media
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Bark
Larger matter added to some horticulture media
to promote drainage
 Adding bark to a soilless mixture usually make
the mix heavier
 Widely used in tree and shrub production
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Organic Media
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Sphagnum Moss
Dehydrated remains of acid bog plants
 Sphagnum moss holds moisture
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Inorganic Media
Vermiculite
 Perlite
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Inorganic Media
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Vermiculite
A mica mineral matter commonly used to start
seed and cuttings
 Holds moisture and has a neutral pH
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Inorganic Media
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Perlite
Natural volcanic ash material
 Helps with soil aeration and water holding
capacity
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Advantages of horticultural
soils

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The soil is sterile
The pH is neutral
The soil is disease and weed free
It is good for starting disease sensitive seeds
(tomato)
It is easy to control the nutrient content of the soil
It improves crop uniformity
It is easy to create a horticulture soil for particular
plant needs
Disadvantages of horticultural
soils
It is expensive
 It is light weight
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Additional materials used in
soilless media
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Sawdust
Has a high carbon to nitrogen ratio
 Makes nitrogen unavailable for plant use
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Additional materials used in
soilless media
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Wood Shavings
Have a high carbon to nitrogen ratio
 Make nitrogen unavailable for plant use
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